Showing papers by "Zhiyong Fan published in 2022"

Neuromorphic-computing-based adaptive learning using ion dynamics in flexible energy storage devices

Abstract: Abstract High-accuracy neuromorphic devices with adaptive weight adjustment are crucial for high-performance computing. However, limited studies have been conducted on achieving selective and linear synaptic weight updates without changing electrical pulses. Herein, we propose high-accuracy and self-adaptive artificial synapses based on tunable and flexible MXene energy storage devices. These synapses can be adjusted adaptively depending on the stored weight value to mitigate time and energy loss resulting from recalculation. The resistance can be used to effectively regulate the accumulation and dissipation of ions in single devices, without changing the external pulse stimulation or preprogramming, to ensure selective and linear synaptic weight updates. The feasibility of the proposed neural network based on the synapses of flexible energy devices was investigated through training and machine learning. The results indicated that the device achieved a recognition accuracy of ∼95% for various neural network calculation tasks such as numeric classification.

Energy Regulation in White-Light-Emitting Diodes

Abstract: : Full electroluminescence (EL) white-light-emitting diodes (WLEDs) are currently a focus of research in the development of white light sources, owing to their outstanding potentiality and advantages in energy saving. The achievement of EL white emission always involves balanced co-excitation of multi-color emissive centers (red/green/blue (R/G/B) or blue/ orange (B/O)). However, R/G/B/O emitters have di ff erent bandgaps, making co-excitation extremely di ffi cult. It is known that excitons formed in a wide-bandgap emitter are easily transferred to any narrow-bandgap emitter. Therefore, the regulation of the energy distribution among multi-color emissive centers is one of the key issues for the realization of white emission and improvement of EL performances and color quality/stability of WLEDs. Currently, many energy regulation strategies have been proposed, promoting the development of full EL-WLEDs. In this Focus Review, we discuss energy-transfer mechanisms and energy regulation strategies in various of WLEDs, including white organic light-emitting diodes (WOLEDs), white quantum-dots light-emitting diodes (WQLEDs), and white perovskite light-emitting diodes (WPeLEDs). Finally, according to their status and challenges, we will o ff er an outlook, which we hope can inspire researchers and make a contribution to the developments of lighting, display fi elds, etc.

Vertical Heterogeneous Integration of Metal Halide Perovskite Quantum-Wires/Nanowires for Flexible Narrowband Photodetectors.

Abstract: Charge collection narrowing (CCN) has been reported to be an efficient strategy to achieve optical filter-free narrowband photodetection (NPD) with metal halide perovskite (MHP) single crystals. However, the necessity of utilizing thick crystals in CCN limits their applications in large scale, flexible, self-driven, and high-performance optoelectronics. Here, for the first time, we fabricate vertically integrated MHP quantum wire/nanowire (QW/NW) array based photodetectors in nanoengineered porous alumina membranes (PAMs) showing self-driven broadband photodetection (BPD) and NPD capability simultaneously. Two cutoff detection edges of the NPDs are located at around 770 and 730 nm, with a full-width at half-maxima (fwhm) of around 40 nm. The optical bandgap difference between the NWs and the QWs, in conjunction with the high carrier recombination rate in QWs, contributes to the intriguing NPD performance. Thanks to the excellent mechanical flexibility of the PAMs, a flexible NPD is demonstrated with respectable performance. Our work here opens a new pathway to design and engineer a nanostructured MHP for novel color selective and full color sensing devices.

Microheater Integrated Nanotube Array Gas Sensor for Parts-Per-Trillion Level Gas Detection and Single Sensor-Based Gas Discrimination.

Abstract: Real-time monitoring of health threatening gases for chemical safety and human health protection requires detection and discrimination of trace gases with proper gas sensors. In many applications, costly, bulky, and power-hungry devices, normally employing optical gas sensors and electrochemical gas sensors, are used for this purpose. Using a single miniature low-power semiconductor gas sensor to achieve this goal is hardly possible, mostly due to its selectivity issue. Herein, we report a dual-mode microheater integrated nanotube array gas sensor (MINA sensor). The MINA sensor can detect hydrogen, acetone, toluene, and formaldehyde with the lowest measured limits of detection (LODs) as 40 parts-per-trillion (ppt) and the theoretical LODs of ∼7 ppt, under the continuous heating (CH) mode, owing to the nanotubular architecture with large sensing area and excellent surface catalytic activity. Intriguingly, unlike the conventional electronic noses that use arrays of gas sensors for gas discrimination, we discovered that when driven by the pulse heating (PH) mode, a single MINA sensor possesses discrimination capability of multiple gases through a transient feature extraction method. These above features of our MINA sensors make them highly attractive for distributed low-power sensor networks and battery-powered mobile sensing systems for chemical/environmental safety and healthcare applications.

Strongly Quantum-Confined Perovskite Nanowire Arrays for Color-Tunable Blue-Light-Emitting Diodes.

Abstract: Color tunability of perovskite light-emitting diodes (PeLEDs) by mixed halide compositional engineering is one of the primary intriguing characteristics of PeLEDs. However, mixed halide PeLEDs are often susceptible to color red-shifting caused by halide ion segregation. In this work, strongly quantum-confined perovskite nanowires (QPNWs) made of CsPbBr3 are grown in nanoporous anodic alumina templates using a closed space sublimation process. By tuning the pore size with atomic layer deposition, QPNWs with a diameter of 6.6 to 2.8 nm have been successfully obtained, with continuous tunable photoluminescence emission color from green (512 nm) to pure blue (467 nm). To better understand the photophysics of QPNWs, carrier dynamics and the benefit of alumina passivation are studied and discussed in detail. Eventually, PeLEDs using various diameters of CsPbBr3 QPNWs are successfully fabricated with cyan color (492 nm) PeLEDs, achieving a record high 7.1% external quantum efficiency (EQE) for all CsPbBr3-based cyan color PeLEDs. Sky blue (481 nm) and pure blue (467 nm) PeLEDs have also been successfully demonstrated, respectively. The work here demonstrates a different approach to achieve quantum-confined one-dimensional perovskite structures and color-tunable PeLEDs, particularly blue PeLEDs.

Substantial Improvement of Operating Stability by Strengthening Metal‐Halogen Bonds in Halide Perovskites

Abstract: Solution‐processed lead halide perovskites (LHPs) hold great promise for low‐cost high‐performance solar cells and light‐emitting devices, but they also suffer from a serious operating instability problem due to the ionic migration and lattice decomposition driven by strong electric fields. Here, considerably suppressed ionic migration and enhanced lattice stability in LHPs with partial substitution of Pb with 3d transition metal (TM: Mn and Ni) are reported. It is experimentally shown that the energy barrier for ionic migration in CsPbBr3 can be increased fourfold by Mn and Ni substitution, even with a small doping level (<4%). However, post‐TM Zn and non‐TM Bi incorporations are less efficient in suppressing ionic migration. The theoretical results reveal that Ni and Mn ions with partially filled 3d orbitals can passivate the active lone‐pair electron of surrounding Pb‐Br octahedrons via a coordination effect and reduce the Pb 6s‐Br 4p antibonding states, resulting in long‐range lattice stabilization and suppressed ionic migration. The Ni incorporation strategy in mixed‐halogen CsPbBr1.5I1.5 is further demonstrated, for which the field‐driven halogen segregation is significantly mitigated and the associated emission color variation is reduced sixfold. This study paves the way for improving the operating stability in LHP‐based optoelectronic and electronic devices.

Regulating the Crystallization Kinetics and Lattice Strain of Lead-Free Perovskites with Perovskite Quantum Dots

Abstract: : The growth of high-quality tin-based perovskite films remains a grand challenge due to uncontrollable crystallization kinetics. Here, we report a facile strategy to realize an epitaxial-like growth of highly oriented tin-based perovskite films with the assistance of perovskite quantum dots (PQDs). Synchrotron-based in situ X-ray scattering results reveal that PQDs can act as nucleation centers to promote the growth of highly oriented perovskite crystals for both FASnI 3 and MASnI 3 systems. Remarkably, the degree of lattice strain can be readily modulated by tuning the lattice mismatch between various PQDs and bulk perovskites, thus reducing defect density and improving efficiencies. The efficiency of MASnI 3 PSCs with PQDs has been pushed to 12.49%, which is the highest of this type reported so far. Furthermore, the film and device stability are enhanced owing to the improved film quality and the protection of hydrophobic ligands from PQDs. images; PL, XRD, XPS, and EQE spectra; GIWAXS intensity profiles and additional patterns; EDX maps; ToF-SIMS depth profiles; Williamson − Hall plots; device performance statistics

Palmitoyl transferases act as potential regulators of tumor-infiltrating immune cells and glioma progression

Abstract: High immune-cell infiltration in glioblastomas (GBMs) leads to immunotherapy resistance. Emerging evidence has shown that zinc finger Asp-His-His-Cyc-type (ZDHHC) palmitoyl transferases participate in regulating tumor progression and the immune microenvironment. In the present study, a large cohort of patients with gliomas from The Cancer Genome Atlas (TCGA) and Rembrandt databases was included to perform omics analysis of ZDHHCs in gliomas. CCK-8, flow cytometry, quantitative real-time PCR, western blotting, and transwell assays were performed to determine the effects of ZDHHC inhibition on glioma cells and microglia. We found that five (ZDHHC11, ZDHHC12, ZDHHC15, ZDHHC22, and ZDHHC23) out of 23 ZDHHCs were aberrantly expressed in gliomas and might play their roles through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. Further results indicated that inhibition of ZDHHCs with 2-bromopalmitate (2-BP) suppressed glioma-cell viability and autophagy, as well as promoted apoptosis. Targeting ZDHHCs also promoted the sensitivity of glioma cells to temozolomide (TMZ) chemotherapy. In addition, the inhibition of ZDHHCs weakened the migratory ability of microglia induced by glioma cells in vitro and in vivo. Taken together, our findings suggest that the inhibition of ZDHHCs suppresses glioma-cell viability and microglial infiltration. Targeting ZDHHCs may be promising for glioma treatments. High immune-cell infiltration in glioblastomas (GBMs) leads to immunotherapy resistance. Emerging evidence has shown that zinc finger Asp-His-His-Cyc-type (ZDHHC) palmitoyl transferases participate in regulating tumor progression and the immune microenvironment. In the present study, a large cohort of patients with gliomas from The Cancer Genome Atlas (TCGA) and Rembrandt databases was included to perform omics analysis of ZDHHCs in gliomas. CCK-8, flow cytometry, quantitative real-time PCR, western blotting, and transwell assays were performed to determine the effects of ZDHHC inhibition on glioma cells and microglia. We found that five (ZDHHC11, ZDHHC12, ZDHHC15, ZDHHC22, and ZDHHC23) out of 23 ZDHHCs were aberrantly expressed in gliomas and might play their roles through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. Further results indicated that inhibition of ZDHHCs with 2-bromopalmitate (2-BP) suppressed glioma-cell viability and autophagy, as well as promoted apoptosis. Targeting ZDHHCs also promoted the sensitivity of glioma cells to temozolomide (TMZ) chemotherapy. In addition, the inhibition of ZDHHCs weakened the migratory ability of microglia induced by glioma cells in vitro and in vivo. Taken together, our findings suggest that the inhibition of ZDHHCs suppresses glioma-cell viability and microglial infiltration. Targeting ZDHHCs may be promising for glioma treatments. Gliomas are the most lethal and common tumors in the central nervous system. Following surgical interventions and aggressive chemoradiotherapeutic treatments, many patients with glioblastomas (GBMs) still exhibit poor prognoses.1Louis D. Ohgaki H. Wiestler O. Cavenee W. Burger P. Jouvet A. Scheithauer B. Kleihues P. The 2007 WHO classification of tumours of the central nervous system.Acta Neuropathol. 2007; 114: 97-109Crossref PubMed Scopus (7868) Google Scholar,2Louis D. Perry A. Reifenberger G. von Deimling A. Figarella-Branger D. Cavenee W. Ohgaki H. Wiestler O. Kleihues P. Ellison D. The 2016 World Health organization classification of tumors of the central nervous system: a summary.Acta Neuropathol. 2016; 131: 803-820Crossref PubMed Google Scholar In recent years, immune-checkpoint inhibitors, such as programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1) and cytotoxic-T-lymphocyte-associated antigen-4 (CTLA-4) inhibitors, have been used as cancer immunotherapies and have made a breakthrough in improving clinical treatments.3Wang H. Xu T. Huang Q. Jin W. Chen J. Immunotherapy for malignant glioma: current status and future directions.Trends Pharmacol. Sci. 2020; 41: 123-138Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar In a phase I clinical trial, intracerebral administration of CTLA-4 inhibitor ipilimumab and PD-1 inhibitor nivolumab in combination with intravenous administration of nivolumab following maximal safe resection of recurrent GBMs was feasible, safe, and associated with encouraging overall survival.4Duerinck J. Schwarze J. Awada G. Tijtgat J. Vaeyens F. Bertels C. Geens W. Klein S. Seynaeve L. Cras L. et al.Intracerebral administration of CTLA-4 and PD-1 immune checkpoint blocking monoclonal antibodies in patients with recurrent glioblastoma: a phase I clinical trial.J. Immunother. Cancer. 2021; 9: e002296Crossref PubMed Scopus (10) Google Scholar In a single-arm phase II clinical trial, a presurgical dose of nivolumab followed by postsurgical nivolumab could remodel the tumor immune microenvironment in resectable GBMs.5Schalper K. Rodriguez-Ruiz M. Diez-Valle R. López-Janeiro A. Porciuncula A. Idoate M. Inogés S. de Andrea C. López-Diaz de Cerio A. Tejada S. et al.Neoadjuvant nivolumab modifies the tumor immune microenvironment in resectable glioblastoma.Nat. Med. 2019; 25: 470-476Crossref PubMed Scopus (285) Google Scholar However, high immune-cell infiltration mediated by GBM cells establishes an immunosuppressive tumor microenvironment, which can induce immunotherapy resistance.6Zheng Z. Zhang J. Jiang J. He Y. Zhang W. Mo X. Kang X. Xu Q. Wang B. Huang Y. Remodeling tumor immune microenvironment (TIME) for glioma therapy using multi-targeting liposomal codelivery.J. Immunother. Cancer. 2020; 8: e000207Crossref PubMed Scopus (16) Google Scholar,7Mohme M. Neidert M. Regli L. Weller M. Martin R. Immunological challenges for peptide-based immunotherapy in glioblastoma.Cancer Treat. Rev. 2014; 40: 248-258Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar Hence, it is critical to identify novel targets associated with high immune-cell infiltration in gliomas. S-palmitoylation is a reversible post-translational lipid modification, which is a universal feature of human cells that controls the localization, stability, and function of various proteins.8Ko P. Dixon S. Protein palmitoylation and cancer.EMBO Rep. 2018; 19: e46666Crossref PubMed Scopus (106) Google Scholar Protein palmitoylation involves the covalent attachment of fatty acyl chains, typically a palmitate (C16:0), to internal cysteine residues of a protein via labile thioester linkages, and palmitoyl transferases catalyze this reaction.9Linder M. Deschenes R. Palmitoylation: policing protein stability and traffic.Nat. Rev. Mol. Cell Biol. 2007; 8: 74-84Crossref PubMed Scopus (720) Google Scholar,10Zhang M. Hang H. Protein S-palmitoylation in cellular differentiation.Biochem. Soc. Trans. 2017; 45: 275-285Crossref PubMed Scopus (27) Google Scholar Palmitoyl transferases are a zinc finger Asp-His-His-Cys-type (ZDHHC) family containing 23 distinct genes (named ZDHHC1–ZDHHC24, excluding ZDHHC10) in mammals.11Greaves J. Chamberlain L. DHHC palmitoyl transferases: substrate interactions and (patho)physiology.Trends Biochem. Sci. 2011; 36: 245-253Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar,12Greaves J. Chamberlain L. New links between S-acylation and cancer.J. Pathol. 2014; 233: 4-6Crossref PubMed Scopus (22) Google Scholar Emerging evidence has shown that ZDHHC-mediated protein palmitoylation participates in regulating tumor progression and the immune microenvironment. For example, loss of ZDHHC9 has been shown to prevent the oncogene, N-Ras, from transforming bone marrow cells in a ZDHHC9-knockout mouse model.13Liu P. Jiao B. Zhang R. Zhao H. Zhang C. Wu M. Li D. Zhao X. Qiu Q. Li J. et al.Palmitoylacyltransferase Zdhhc9 inactivation mitigates leukemogenic potential of oncogenic Nras.Leukemia. 2016; 30: 1225-1228Crossref PubMed Scopus (26) Google Scholar In colorectal cancer, ZDHHC3 has been found to be upregulated and to promote protein PD-L1 palmitoylation, which weakens T cell immune responses against tumors. Furthermore, inhibition of PD-L1 palmitoylation can activate anti-cancer immunity.14Yao H. Lan J. Li C. Shi H. Brosseau J. Wang H. Lu H. Fang C. Zhang Y. Liang L. et al.Inhibiting PD-L1 palmitoylation enhances T-cell immune responses against tumours.Nat. Biomed. Eng. 2019; 3: 306-317Crossref PubMed Scopus (120) Google Scholar A recent study showed that IFNGR1 palmitoylation stabilized IFNGR1 to drive immune evasion and immunotherapy resistance in tumors.15Du W. Hua F. Li X. Zhang J. Li S. Wang W. Zhou J. Wang W. Liao P. Yan Y. et al.Loss of optineurin drives cancer immune evasion via palmitoylation-dependent IFNGR1 lysosomal sorting and degradation.Cancer Discov. 2021; https://doi.org/10.1158/2159-8290.CD-20-1571Crossref Scopus (10) Google Scholar In the central nervous system, compared with that in normal brain tissues, glioma tissues exhibit aberrant protein palmitoylation.16Chen X. Li H. Fan X. Zhao C. Ye K. Zhao Z. Hu L. Ma H. Wang H. Fang Z. Protein palmitoylation regulates cell survival by modulating XBP1 activity in glioblastoma multiforme.Mol. Ther. Oncolytics. 2020; 17: 518-530Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar Previous studies have found that several ZDHHCs indeed participated in regulating glioma cell survival, transition of stem cells, glycolysis, chemotherapy resistance, and progression. For example, ZDHHC18 and ZDHHC23 were distributed in the context of their specific niches in different GBM subsets to regulate the cellular plasticity of these subtypes, which contribute to the transition of glioma stem cells in GBM and cell survival under the stressful tumor microenvironment.17Chen X. Hu L. Yang H. Ma H. Ye K. Zhao C. Zhao Z. Dai H. Wang H. Fang Z. DHHC protein family targets different subsets of glioma stem cells in specific niches.J. Exp. Clin. Cancer Res. 2019; 38: 25Crossref PubMed Scopus (24) Google Scholar ZDHHC17 could target JNK and p38 mitogen-activated protein kinase (MAPK) to drive GBM chemotherapy resistance.18Chen X. Hao A. Li X. Ye K. Zhao C. Yang H. Ma H. Hu L. Zhao Z. Hu L. et al.Activation of JNK and p38 MAPK mediated by ZDHHC17 drives glioblastoma multiforme development and malignant progression.Theranostics. 2020; 10: 998-1015Crossref PubMed Scopus (25) Google Scholar Moreover, ZDHHC5-mediated EZH2 palmitoylation was shown to drive p53-mutant glioma malignant development and progression.19Chen X. Ma H. Wang Z. Zhang S. Yang H. Fang Z. EZH2 palmitoylation mediated by ZDHHC5 in p53-mutant glioma drives malignant development and progression.Cancer Res. 2017; 77: 4998-5010Crossref PubMed Scopus (47) Google Scholar A recent study reported that GLUT1 palmitoylation-mediated DHHC9 promotes GBM glycolysis and tumorigenesis.20Zhang Z. Li X. Yang F. Chen C. Liu P. Ren Y. Sun P. Wang Z. You Y. Zeng Y. et al.DHHC9-mediated GLUT1 S-palmitoylation promotes glioblastoma glycolysis and tumorigenesis.Nat. Commun. 2021; 12: 5872Crossref PubMed Scopus (6) Google Scholar Nevertheless, the expression profiles and potential biological functions of ZDHHCs, as well as whether ZDHHCs may represent a drug target in gliomas, have yet to be well elucidated. In the present study, we first investigated the expression profiles of ZDHHCs through corresponding public datasets. Next, we explored the correlation between the differential expression of ZDHHCs and survival times of patients with glioma. In addition, we assessed the potential roles and mechanisms of ZDHHCs in gliomas via performing Gene Ontology (GO) enrichment analysis, immune-infiltration analysis, and gene set enrichment analysis (GSEA). Finally, CCK-8, flow cytometry, quantitative real-time PCR, western blotting, transwell, and immunofluorescence assays were also performed. The details of what we have done were summarized and presented in Figure S1 and Table 1. The ZDHHCs are a gene family comprising 23 distinct genes. We first analyzed Pearson correlations among these genes. In lower grade gliomas (LGGs) (grades II and III), most ZDHHCs were positively associated with each other. Only ZDHHC12 was negatively correlated with other ZDHHCs (except for ZDHHC5 and ZDHHC19) in LGGs (Figure S2A). In GBMs (grade IV), Pearson correlations among ZDHHCs were lower than those in LGGs (Figure S1B). Next, we compared transcriptional levels of ZDHHCs between glioma tissues and normal brain tissues in The Cancer Genome Atlas (TCGA) database. As shown in Figure 1 and Table 1 (column 1), five ZDHHCs (ZDHHC2, ZDHHC4, ZDHHC9, ZDHHC12, and ZDHHC15) were upregulated and two ZDHHCs (ZDHHC11 and ZDHHC23) were downregulated in glioma tissues. Interestingly, ZDHHC22 was upregulated in LGGs, whereas it was downregulated in GBMs (Figure 1G). Microarray data from the Rembrandt database presented a similar result (Figure S3). However, we did not observe differential expression levels of ZDHHC9 between normal brain tissues and glioma tissues in the Rembrandt database (Figure S3C). In addition to gliomas, data from the TIMER (https://cistrome.shinyapps.io/timer/) dataset showed that ZDHHC2, ZDHHC4, ZDHHC9, ZDHHC11, ZDHHC12, ZDHHC15, ZDHHC22, and ZDHHC23 were also aberrantly expressed in the majority of tumors (Figure S4).21Li T. Fan J. Wang B. Traugh N. Chen Q. Liu J. Li B. Liu X. TIMER: a web server for comprehensive analysis of tumor-infiltrating immune cells.Cancer Res. 2017; 77: e108-e110Crossref PubMed Scopus (0) Google Scholar In gliomas, compared with those in LGGs, the expression levels of six ZDHHCs (ZDHHC2, ZDHHC4, ZDHHC9, ZDHHC12, ZDHHC15, and ZDHHC23) were higher in GBMs. In contrast, ZDHHC11 and ZDHHC22 expression levels in GBMs were lower than those in LGGs (Figures S5A–S5H). With the exceptions of ZDHHC4 and ZDHHC15, there was a difference in ZDHHC mRNA expression among the three molecular subtypes of gliomas (Figures S5I–S5P). Moreover, isocitrate dehydrogenase (IDH) wild-type and mutant gliomas also presented differential expression levels of ZDHHCs (Figures S5Q–S5X). We also evaluated these ZDHHC protein levels through the Human Protein Atlas (HPA) database. There were no data related to ZDHHC22 protein levels in this database. As shown in Figure 2 and Table 1 (column 2 and column 3), compared with normal brain tissues, ZDHHC2, ZDHHC9, ZDHHC12, and ZDHHC15 protein levels were upregulated in glioma tissues, while ZDHHC11 and ZDHHC23 protein levels were downregulated. The protein levels of the five ZDHHCs (ZDHHC2, ZDHHC11, ZDHHC12, ZDHHC15, and ZDHHC23) were consistent with their corresponding mRNA levels.Table 1Omics analysis of ZDHHCs in gliomasGenesRNA expression levels (tumor versus normal)Protein expression levels (percent account for total included glioma cases)Protein expression levels (normal cerebral cortex)Methylation levels (IDH mutant versus wild type)Mutation frequencyZDHHC1no significancenot detectednot detectedhypermethylation0ZDHHC2upregulatednot detected: 50%low: 50%not detectedhypermethylation0.6%ZDHHC3no significancenot detected: 25%low: 8%medium: 58%high: 9%mediumhypermethylation1.4%ZDHHC4upregulatednot detected: 91%medium: 9%not detectedhypermethylation1.2%ZDHHC5no significancenot detected: 25%low: 58%medium: 9%high: 8%lowhypermethylation0ZDHHC6no significancenot detected: 50%low: 17%medium: 33%not detectedhypermethylation1.7%ZDHHC7no significancenot detectednot detectedhypermethylation0.2%ZDHHC8no significancenot detected: 46%low: 54%not detectedhypermethylation0.6%ZDHHC9upregulatednot detected: 36%low: 28%medium: 36%lowno significance1.4%ZDHHC11downregulatednot detected: 100%lowhypermethylation1.6%ZDHHC12upregulatedlow: 8%medium: 75%high: 17%mediumhypermethylation1%ZDHHC13no significancenot detected: 84%low: 8%medium: 8%not detectedhypermethylation1.6%ZDHHC14no significancenot detected: 20%low: 50%medium: 20%high: 10%mediumhypermethylation2.1%ZDHHC15upregulatednot detected: 42%low: 42%medium: 16%not detectedno significance2.9%ZDHHC16no significancenot detectednot detectedhypermethylation0.4%ZDHHC17no significancelow: 18%medium: 73%high: 9%highhypermethylation0.6%ZDHHC18no significancenot detected: 27%low: 18%high: 55%not detectedhypermethylation0.2%ZDHHC19no significancenot availablenot availablehypermethylation2.9%ZDHHC20no significancenot detected: 50%low: 42%medium: 8%not detectedno significance1.9%ZDHHC21no significancelow: 8%medium: 50%high: 42%mediumhypomethylation2.3%ZDHHC22upregulated in LGGsdownregulated in GBMnot availablenot availablehypomethylation0.8%ZDHHC23downregulatednot detected: 73%low: 18%medium: 9%mediumhypomethylation1.4%ZDHHC24no significancenot detected: 58%low: 42%not detectedhypomethylation0 Open table in a new tab Figure 2Relative protein levels of seven ZDHHCs in normal brain tissues and glioma tissuesShow full caption(A–G) Histograms of ZDHHC expression levels in glioma samples from the Protein Atlas. In total, 11 to 12 samples were analyzed for ZDHHCs. Immunohistochemical (IHC) staining was evaluated as high, medium, or low staining or not detected. No information could be retrieved for ZDHHC22. (H–N) Representative IHC staining for ZDHHCs in normal brain tissues and glioma tissues is shown.View Large Image Figure ViewerDownload Hi-res image Download (PPT) (A–G) Histograms of ZDHHC expression levels in glioma samples from the Protein Atlas. In total, 11 to 12 samples were analyzed for ZDHHCs. Immunohistochemical (IHC) staining was evaluated as high, medium, or low staining or not detected. No information could be retrieved for ZDHHC22. (H–N) Representative IHC staining for ZDHHCs in normal brain tissues and glioma tissues is shown. DNA methylation of the CpG island of a gene promoter is the most common mechanism that results in the repression of gene expression.22Alhaji S. Ngai S. Abdullah S. Silencing of transgene expression in mammalian cells by DNA methylation and histone modifications in gene therapy perspective.Biotechnol. Genet. Eng. Rev. 2019; 35: 1-25Crossref PubMed Scopus (13) Google Scholar We explored the methylation levels of ZDHHC promoters via the MethSurv (https://biit.cs.ut.ee/methsurv/) and Xena Functional Genomics Explorer (https://xenabrowser.net/heatmap/) tools.23Modhukur V. Iljasenko T. Metsalu T. Lokk K. Laisk-Podar T. Vilo J. MethSurv: a web tool to perform multivariable survival analysis using DNA methylation data.Epigenomics. 2018; 10: 277-288Crossref PubMed Scopus (170) Google Scholar,24Goldman M. Craft B. Hastie M. Repečka K. McDade F. Kamath A. Banerjee A. Luo Y. Rogers D. Brooks A. et al.Visualizing and interpreting cancer genomics data via the Xena platform.Nat. Biotechnol. 2020; 38: 675-678Crossref PubMed Scopus (757) Google Scholar Apart from ZDHHC11, ZDHHC22, and ZDHHC23, we noticed that other ZDHHCs (e.g., ZDHHC18 and ZDHHC19) exhibited low mRNA levels in both glioma tissues and normal brain tissues. Next, we investigated the methylation levels of ZDHHC promoters in gliomas. As shown in Figure S6, the promoters of ZDHHC7, ZDHHC11, ZDHHC18, and ZDHHC19 presented high methylation levels, which might account for the low expression levels of these genes in gliomas. However, there were no high methylation levels of the promoters of ZDHHC22 and ZDHHC23. In addition to that, we also compared methylation levels between IDH wild-type and mutant glioma samples. With respect to IDH wild-type gliomas, the majority of ZDHHCs presented higher methylation levels in IDH mutant glioma samples (Figure S7; Table 1, column 5). Gene mutations frequently occur during tumor development. Many patients with LGGs harbor IDH gene-family mutations, which were consequently included in the classification of newly diagnosed gliomas by the World Health Organization in 2016.2Louis D. Perry A. Reifenberger G. von Deimling A. Figarella-Branger D. Cavenee W. Ohgaki H. Wiestler O. Kleihues P. Ellison D. The 2016 World Health organization classification of tumors of the central nervous system: a summary.Acta Neuropathol. 2016; 131: 803-820Crossref PubMed Google Scholar Next, we investigated genomic alterations of each ZDHHC gene in gliomas by using data available from the cBioPortal (http://www.cbioportal.org/datasets).25Cerami E. Gao J. Dogrusoz U. Gross B. Sumer S. Aksoy B. Jacobsen A. Byrne C. Heuer M. Larsson E. et al.The cBio cancer genomics portal: an open platform for exploring multidimensional cancer genomics data.Cancer Discov. 2012; 2: 401-404Crossref PubMed Scopus (8570) Google Scholar,26Gao J. Aksoy B. Dogrusoz U. Dresdner G. Gross B. Sumer S. Sun Y. Jacobsen A. Sinha R. Larsson E. et al.Integrative analysis of complex cancer genomics and clinical profiles using the cBioPortal.Sci. Signal. 2013; 6: pl1Crossref PubMed Scopus (7900) Google Scholar Results presented in Figure S8 and Table 1 (column 6) showed that 21 LGGs and 22 GBMs out of all ZDHHCs harbored at least one type of genomic alteration (i.e., missense mutation, amplification, or deep deletion). The overall mutation frequency of ZDHHCs in LGGs was higher than that in GBMs. Among the 23 genes, ZDHHC14, ZDHHC15, ZDHHC19, and ZDHHC21 were the most frequently altered genes (2.1%, 2.9%, 2.9%, and 2.1%, respectively) in LGGs. However, there was no significant difference in survival times between altered and non-altered groups in gliomas (data not shown). After obtaining the expression profiles of ZDHHCs, we then searched for an association between ZDHHC expression levels and survival times of patients with glioma. We extracted hazard ratios (HRs) from TCGA and Rembrandt databases by using an optimized algorithm via the Gliovis tool. As shown in Table 2, patients with glioma and with high expression levels of ZDHHC1, ZDHHC4, ZDHHC5, ZDHHC12, ZDHHC13, ZDHHC15, ZDHHC18, ZDHHC23, and ZDHHC24 had a poor overall survival. In contrast, data from the Rembrandt database showed that high expression levels of ZDHHC1, ZDHHC3, ZDHHC4, ZDHHC5, ZDHHC7, ZDHHC8, ZDHHC9, ZDHHC12, ZDHHC15, and ZDHHC23 were negatively associated with survival times of patients with glioma (Table 2). In TCGA database, patients with low expression levels of ZDHHC8, ZDHHC11, ZDHHC16, ZDHHC17, ZDHHC19, ZDHHC20, ZDHHC21, and ZDHHC22 showed poor survival times. However, only ZDHHC11, ZDHHC16, ZDHHC18, and ZDHHC22 expression levels were positively correlated with the overall survival of patients with glioma in the Rembrandt database (Table 2).Table 2Prognostic values of ZDHHCs in gliomasGenesTCGARembrandtHazard ratiop valuePrognostic valueHazard ratiop valuePrognostic valueZDHHC10.28 (0.21–0.38)<0.01poorer prognosis0.61 (0.48–0.76)<0.01poorer prognosisZDHHC21.27 (0.99–1.65)>0.05no significance0.94 (0.75–1.17)>0.05no significanceZDHHC30.87 (0.68–1.13)>0.05no significance0.64 (0.52–0.81)<0.05poorer prognosisZDHHC40.36 (0.28–0.48)<0.01poorer prognosis0.52 (0.41–0.65)<0.05poorer prognosisZDHHC50.3 (0.23–0.40)<0.01poorer prognosis0.62 (0.5–0.78)<0.05poorer prognosisZDHHC61.11 (0.86–1.43)>0.05no significance1.22 (0.98–1.53)>0.05no significanceZDHHC70.84 (0.65–1.09)>0.05no significance0.67 (0.53–0.83)<0.01poorer prognosisZDHHC81.31 (1.01–1.7)<0.05better prognosis1.24 (0.99–1.55)>0.05no significanceZDHHC90.8 (0.62–1.04)>0.05no significance1.04 (0.83–1.3)>0.05no significanceZDHHC111.47 (1.13–1.91)<0.01better prognosis1.62 (1.3–2.03)<0.01better prognosisZDHHC120.22 (0.17–0.3)<0.01poorer prognosis0.43 (0.34–0.54)<0.01poorer prognosisZDHHC130.43 (0.33–0.65)<0.01poorer prognosis1.04 (0.84–1.3)>0.05no significanceZDHHC140.93 (0.72–1.19)>0.05no significance1.15 (0.92–1.44)>0.05no significanceZDHHC150.5 (0.38–0.65)<0.01poorer prognosis0.66 (0.53–0.83)<0.01poorer prognosisZDHHC161.48 (1.14–1.91)<0.01better prognosis1.61 (1.29–2.01)<0.01better prognosisZDHHC172.96 (2.24–3.9)<0.01better prognosis0.89 (0.71–1.11)>0.05no significanceZDHHC180.24 (0.18–0.32)<0.01poorer prognosis1.59 (1.27–1.99)<0.01better prognosisZDHHC191.49 (1.16–1.93)<0.01better prognosis0.87 (0.70–1.09)>0.05no significanceZDHHC201.33 (1.03–1.72)<0.05better prognosis1.04 (0.84–1.3)>0.05no significanceZDHHC212.39 (1.83–3.11)<0.01better prognosis1.68 (1.34–2.11)<0.01better prognosisZDHHC226.56 (4.79–9.07)<0.01better prognosis3.03 (2.4–3.84)<0.01better prognosisZDHHC230.28 (0.21–0.37)<0.01poorer prognosis0.76 (0.61–0.94)<0.01poorer prognosisZDHHC240.4 (0.31–0.53)<0.01poorer prognosis0.93 (0.75–1.06)>0.05no significance Open table in a new tab Combined with the above results, we noticed that there were five ZDHHCs (ZDHHC11, ZDHHC12, ZDHHC15, ZDHHC22, and ZDHHC23) that were not only differentially expressed in gliomas but were also associated with the overall survival of patients with glioma. Therefore, we used these five ZDHHCs to establish a ZDHHC-related risk signature via the assistance of a clinical bioinformatics tool (https://www.aclbi.com/static/index.html#/).27Zhang Z. Lin E. Zhuang H. Xie L. Feng X. Liu J. Yu Y. Construction of a novel gene-based model for prognosis prediction of clear cell renal cell carcinoma.Cancer Cell Int. 2020; 20: 27Crossref PubMed Scopus (45) Google Scholar,28Lin W. Wu S. Chen X. Ye Y. Weng Y. Pan Y. Chen Z. Chen L. Qiu X. Qiu S. Characterization of hypoxia signature to evaluate the tumor immune microenvironment and predict prognosis in glioma groups.Front. Oncol. 2020; 10: 796Crossref PubMed Scopus (70) Google Scholar By using the “glmnet” package in R, the least absolute shrinkage and selection operator (Lasso) regression model was selected to minimize overfitting and to identify the most significant survival-associated ZDHHCs in gliomas, which were found to be ZDHHC12, ZDHHC15, ZDHHC22, and ZDHHC23 (Figure S9). Risk scores were calculated for each sample (risk score=0.4654∗ZDHHC12+0.1485∗ZDHHC15+(−0.2919)∗ZDHHC22+0.1888∗ZDHHC23). As shown in Figure S9, ZDHHC12, ZDHHC15, and ZDHHC23 expression levels were higher in the high-risk group, while ZDHHC22 expression was higher in the low-risk group. Kaplan-Meier analysis showed that patients with glioma in the high-risk group had poorer survival times compared with those of the low-risk group (Figure 3A ). To determine the prognostic significance of our ZDHHC-related risk signature, time-dependent receiver operating characteristic (ROC) curve analysis was performed. The area under the curve (AUC) values for the 1-, 3-, and 5-year ROC curves each reached 0.8, indicating that our ZDHHC-related risk signature yielded a good sensitivity and specificity for predicting the prognoses of patients with glioma (Figure 3B). We also evaluated prognostic values of the ZDHHC-related risk signature in separated IDH wild-type and mutant gliomas. As shown in Figures S10, 3C, and 3D, ZDHHC-related risk signature also presented an acceptable sensitivity and specificity for predicting the prognoses of patients with IDH wild-type gliomas. However, it seems that there were no values of ZDHHC-related risk signature for predicting the prognoses of patients with IDH mutant gliomas (Figures 3E, 3F, and S11). The microarray data from the Rembrandt dataset were used to perform GO enrichment analysis. Each ZDHHC was divided into high- and low-expression groups according to the corresponding expression levels. The top-50 differentially expressed genes between the high- and low-expression groups of each ZDHHC are shown in the heatmaps in Figures S12A and S13. We found that ZDHHC11 might regulate cell extracellular matrix organization (Figure S12B). We observed that ZDHHC12 and ZDHHC22 were related to leukocyte migration (Figures 4A and 4C ). In contrast, ZDHHC15 and ZDHHC23 were mainly involved in regulating the cell cycle and development (Figures 4B and 4D). To validate whether ZDHHC12 and ZDHHC22 were indeed associated with infiltration of immune cells, we performed immune-cell infiltration analysis. We noticed that ZDHHC12 expression was positively related to immune-cell infiltration, while ZDHHC22 expression was negatively related to immune-cell infiltration in pan-cancer (Figures 5A and 5C ). Furthermore, compared with other tumors, ZDHHC12- or ZDHHC22-associated immune-cell infiltration showed a high specificity for LGGs and GBMs (Figures 5A and 5C). In gliomas, higher macrophages and microglia, memory CD4+ T cell, B cell, regulatory T cell, myeloid-derived suppressor cell, and natural killer T cell infiltration were presented in ZDHHC12 high-expression group compared with that in low-expression group. In contrast, ZDHHC22 expression was negatively related to infiltration of these immune cells (Figures 5B and 5D). Considering that leukocyte migration is mediated by chemokines, we then analyzed the correlations between ZDHHC expression levels and related chemokines. As shown in Figure S14, ZDHHC12 was positively associated with most chemokines in gliomas, while ZDHHC22 was negatively associated with the majority of the chemokines analyzed. These results further support that ZDHHC12 and ZDHHC22 regulated leukocyte migration via chemokines. Importantly, immune-checkpoint-blockade-mediated cancer immunotherapies are promising strategies for clinical treatments.29Wright J. Powers A. Johnson D. Endocrine toxicities of immune checkpoint inhibitors.Nat. Rev. Endocrinol. 2021; 17: 389-399Crossref PubMed Scopus (26) Google Scholar We found that ZDHHC12 was positively associated with the immune checkpoints, PD-L1, LAG3, and CTLA-4, while ZDHHC22 was negatively associated with these markers (Figure S15). Next, we performed a GSEA to explore related biological mechanisms. We found that four out of five ZDHHCs were enriched in the oncogenic phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway (Figure S16). Low expression levels of ZDHHC11 and ZDHHC22 were associated with the activation of PI3K/AKT signaling pathway (Fig

Temperature-Modulated Selective Detection of Part-per-Trillion NO2 Using Platinum Nanocluster Sensitized 3D Metal Oxide Nanotube Arrays.

Abstract: Semiconductor chemiresistive gas sensors play critical roles in a smart and sustainable city where a safe and healthy environment is the foundation. However, the poor limits of detection and selectivity are the two bottleneck issues limiting their broad applications. Herein, a unique sensor design with a 3D tin oxide (SnO2 ) nanotube array as the sensing layer and platinum (Pt) nanocluster decoration as the catalytic layer, is demonstrated. The Pt/SnO2 sensor significantly enhances the sensitivity and selectivity of NO2 detection by strengthening the adsorption energy and lowering the activation energy toward NO2 . It not only leads to ultrahigh sensitivity to NO2 with a record limit of detection of 107 parts per trillion, but also enables selective NO2 sensing while suppressing the responses to interfering gases. Furthermore, a wireless sensor system integrated with sensors, a microcontroller, and a Bluetooth unit is developed for the practical indoor and on-road NO2 detection applications. The rational design of the sensors and their successful demonstration pave the way for future real-time gas monitoring in smart home and smart city applications.

Uncooled self-powered hemispherical biomimetic pit organ for mid- to long-infrared imaging

Abstract: Infrared vision is highly desirable for applications in multifarious fields. Of the few species with this visual capability, snakes have exceptional infrared perception with the assistance of pit organs. Inspired by the pit organ design we present here a hemispherical biomimetic infrared imaging device. The devices use high-density ionic thermoelectric polymer nanowire arrays that serve as the sensing nerve cells. The individual nanowires exhibit notable voltage response to temperature variation in test objects. An infrared sensor array with 625 pixels on the hemispherical substrate is successfully demonstrated with an ultrawide field of view up to 135°. The device can image body temperature objects without a cooling system and external power supply. This work opens up opportunities for the design and fabrication of bioinspired infrared imaging devices based on emerging ionic thermoelectric materials.

Image processing with a multi-level ultra-fast three dimensionally integrated perovskite nanowire array.

Abstract: Besides its ubiquitous applications in optoelectronics, halide-perovskites (HPs) have also carved a niche in the domain of resistive switching memories (Re-RAMs). However owing to the material and electrical instability challenges faced by HP thin-films, rarely perovskite Re-RAMs are used to experimentally demonstrate data processing which is a fundamental requirement for neuromorphic applications. Here, for the first time, lead-free, ultrahigh density HP nanowire (NW) array Re-RAM has been utilized to demonstrate image processing via design of convolutional kernels. The devices exhibited superior switching characteristics including a high endurance of 5 × 106 cycles, an ultra-fast erasing and writing speed of 900 ps and 2 ns, respectively, and a retention time >5 × 104 s for the resistances. The work is bolstered by an in-depth mechanistic study and first-principles simulations which provide evidence of electrochemical metallization triggering the switching. Employing the robust multi-level switching behaviour, image processing functions of embossing, outlining and sharpening were successfully implemented.

Robust Lead‐Free Perovskite Nanowire Array‐Based Artificial Synapses Exemplifying Gestalt Principle of Closure via a Letter Recognition Scheme

Abstract: The Gestalt principles of perceptual learning elucidate how the human brain categorizes and comprehends a set of visual elements grouped together. One of the principles of Gestalt perceptual learning is the law of closure which propounds that human perception has the proclivity to visualize a fragmented object as a preknown whole by bridging the missing gaps. Herein, a letter recognition scheme emulating the Gestalt closure principle is demonstrated, utilizing artificial synapses made of 3D integrated MA3Bi2I9 (MBI) perovskite nanowire (NW) array. The artificial synapses exhibit short‐term plasticity (STP) and long‐term potentiation (LTP) and a transition from STP to LTP with increasing number of input electrical pulses. Initiatory ab initio molecular dynamics (AIMD) simulations attribute the conductance change in the MBI NW artificial synapses to the rotation of MA+ clusters, culminating in charge exchange between MA+ and Bi2I93−. Each device yields 40 conductance states with excellent retention >105 s, minimal variation (2σ/mean) <10%, and endurance of ≈105 cycles. MBI NW‐based artificial neural network (ANN) is constructed to recognize fragmented letters alike their distinction in unabridged form and also the gradual withering of synaptic connectivity with engendered missing fragments is demonstrated, thereby successfully implementing Gestalt closure principle.

Programmable Nanoarchitectonics of Pore Array for Electronic-Nose-Based Early Disease Diagnose

Abstract: In this article, we present a novel electronic nose fabrication process based on highly programmable anodic aluminum oxide (AAO) nanoarchitectonics and ultrasonic spray pyrolysis (USP) deposition. Featuring an ultralow manufacturing cost, the deposited material’s morphology can be accurately controlled with fabricated general-purpose AAO template. Compared with nonstandard lithography-based template fabrication method, the need of complicated Bosch etching process and its associated complex process parameter tuning is eliminated. As a result, the cost-effective mass production of 3-D nanotemplate-based material and devices can be enabled. In addition, the target material’s limited coverage and time efficiency issues widely existing in the previous deposition methods are well-addressed by our customized USP deposition, especially for the 3-D nanotemplate with large surface-to-volume ratio, leading to significantly improved gas-sensing performance. Moreover, the proposed fabrication recipe, together with the adopted gas recognition algorithms based on linear discriminant analysis (LDA), is validated based on the reported extensive measurement results for five gas biomarkers widely exploited for patients’ exhaled gas-sensing and recognition applications. This shows great potential for the early disease diagnose of diabetes, breast cancer, acute lung injury, colon diseases, lung cancer, and so on.

Three-Dimensional Nanopillar Arrays-Based Efficient and Flexible Perovskite Solar Cells with Enhanced Stability.

Abstract: Perovskite nanopillars (PNPs) are propitious candidates for solar irradiation harvesting and are potential alternatives to thin films in flexible photovoltaics. To realize efficient daily energy output, photovoltaics must absorb sunlight over a broad range of incident angles and wavelengths congruent with the solar spectrum. Herein, we report highly periodic three-dimensional (3D) PNP-based flexible photovoltaics possessing a core-shell structure. The vertically aligned PNP arrays demonstrate up to 95.70% and 75.10% absorption at peak and under an incident angle of 60°. The efficient absorption and the orthogonal carrier collection facilitate an external quantum efficiency of 84.0%-89.18% for broadband wavelength. PNPs have been successfully implemented in flexible solar cells. The porous alumina membrane protects PNPs against water and oxygen intrusion and thereby imparts robustness to photovoltaic devices. Meanwhile, the excellent tolerance to mechanical stress/strain enables our unique PNP-based device to provide efficient solar-to-electricity conversion while undergoing mechanical bending.

Organic-inorganic hybrid self-pigmenting effect of anodic aluminium oxide membranes

Abstract: Anodic aluminium oxide (AAO) membranes with hexagonally packed nanochannel arrays have been utilized as a promising template to develop functional nanostructures. The characteristics of the AAO membranes are crucial to...

Schottky-Contacted WSe 2 Hot-Electron Photodetectors with Fast Response and High Sensitivity

Abstract: : Utilizing the short lifetime of hot electrons, ultrasensitive hot-electron photodetectors with fast response speed can be developed that have the potential to carve a niche among the photoconductive devices. Herein, high-performance WSe 2 photodetectors are fabricated based on hot-electron transportation, in which an ultrathin Al 2 O 3 layer enables screening of high-energy hot electrons and promises ultrasensitive response to incident light, and the built-in electric fi eld in Schottky junctions separates the photoinduced carriers for fast transient recovery. The hot-electron photodetectors demonstrated a high recti fi cation ratio of 10 7 and an extremely low dark current of 1 pA/ μ m with a high I light / I dark ratio of 1.8 × 10 6 . Moreover, a high responsivity of 3.69 A/W and detectivity of 2.39 × 10 13 Jones at an incident light power of 5.0 μ W/cm 2 are simultaneously achieved. The present strategy o ff ers an alternative route for ultrasensitive photodetectors with fast response.

Strongly Quantum-Con fi ned Perovskite Nanowire Arrays for Color-Tunable Blue-Light-Emitting Diodes

Abstract: : Color tunability of perovskite light-emitting diodes (PeLEDs) by mixed halide compositional engineering is one of the primary intriguing characteristics of PeLEDs. However, mixed halide PeLEDs are often susceptible to color red-shifting caused by halide ion segregation. In this work, strongly quantum-con fi ned perovskite nanowires (QPNWs) made of CsPbBr 3 are grown in nanoporous anodic alumina templates using a closed space sublimation process. By tuning the pore size with atomic layer deposition, QPNWs with a diameter of 6.6 to 2.8 nm have been successfully obtained, with continuous tunable photoluminescence emission color from green (512 nm) to pure blue (467 nm). To better understand the photophysics of QPNWs, carrier dynamics and the bene fi t of alumina passivation are studied and discussed in detail. Eventually, PeLEDs using various diameters of CsPbBr 3 QPNWs are successfully fabricated with cyan color (492 nm) PeLEDs, achieving a record high 7.1% external quantum e ffi ciency (EQE) for all CsPbBr 3 -based cyan color PeLEDs. Sky blue (481 nm) and pure blue (467 nm) PeLEDs have also been successfully demonstrated, respectively. The work here demonstrates a di ff erent approach to achieve quantum-con fi ned one-dimensional perovskite structures and color-tunable PeLEDs, particularly blue PeLEDs.

(Invited, Digital Presentation) Nanostructured Perovskite Resistive RAM for Next Generation Data Storage

Abstract: Resistive RAMs (Re-RAMs) have emerged as a propitious candidate among next generation non volatile memories because of their strikingly fast speed, prolonged data retention ability and high storage density. Herein, we developed an electrochemical metallization (ECM) based Re-RAM with three-dimensionally integrated single-crystalline perovskite (methyl ammonium lead halide or MAPbX3 where X=I, Br and Cl) quantum wire (PQW)/ nanowire (PNW) array embedded in a nano-engineered porous alumina membrane (PAM) serving as the switching medium. The PQWs and PNWs were grown inside the PAM template by a vapor-solid-solid-reaction (VSSR) process and were clubbed between silver (Ag) and aluminum (Al) contacts. The nanostructured perovskite Re-RAM exhibited 100 ps switching speed which is a record for perovskite Re-RAMs and also among the fastest for all types of Re-RAMs reported. The fast switching was attributed to the increased ionic (Ag+) and electronic mobility and subsequent accelerated filament formation within the body of the monocrystalline PQWs/PNWs. The PAM scaffolding imparted material and electrical stability to the environmentally delicate perovskite. As a consequence, we were able to obtain a record long (among perovskite Re-RAMs) estimated retention time > 28 years and record-high (among perovskite Re-RAMs) uninhibited cyclic endurance of 6×106 cycles. Also, utilizing the ultra-high density (2×1011/cm2) of the PQWs, a 14 nm lateral dimension ultra-small memory cell was built. In conjunction with multi-bit switching, an effective device footprint of 76.5 nm2 was achieved for a single bit storage. Further, as a concept proof, an 8×8 Re-RAM crossbar array device was fabricated which demonstrated temporally robust alphabetic data storage, with a unique metal-semiconductor-insulator-metal (MSIM) architecture to alleviate the sneaky path problem. The MSIM scheme based on quasi-self-selecting elements, demonstrated a strong potential for unhindered scalability in the future, a problem often encountered with integrating external selecting diodes and transistors. The PQW/PNW Re-RAMs also responded to light stimuli, exhibiting optical programmability among the low resistance states. In summary, these intriguing results propel perovskite Re-RAMs to the state-of-the-art standard and demonstrate an attractive potency for PQW/PNW devices to be used as an alternative technology in future storage and computing modules.

Low-Energy Hydrogen Ions Enable Efficient Room-Temperature and Rapid Plasma Hydrogenation of TiO2 Nanorods for Enhanced Photoelectrochemical Activity.

Abstract: Hydrogenation is a promising technique to prepare black TiO2 (H-TiO2 ) for solar water splitting, however, there remain limitations such as severe preparation conditions and underexplored hydrogenation mechanisms to inefficient hydrogenation and poor photoelectrochemical (PEC) performance to be overcome for practical applications. Here, a room-temperature and rapid plasma hydrogenation (RRPH) strategy that realizes low-energy hydrogen ions of below 250 eV to fabricate H-TiO2 nanorods with controllable disordered shell, outperforming incumbent hydrogenations, is reported. The mechanisms of efficient RRPH and enhanced PEC activity are experimentally and theoretically unraveled. It is discovered that low-energy hydrogen ions with fast subsurface transport kinetics and shallow penetration depth features, enable them to directly penetrate TiO2 via unique multiple penetration pathways to form controllable disordered shell and suppress bulk defects, ultimately leading to improved PEC performance. Furthermore, the hydrogenation-property experiments reveal that the enhanced PEC activity is mainly ascribed to increasing band bending and bulk defect suppression, compared to reported H-TiO2 , a superior photocurrent density of 2.55 mA cm-2 at 1.23 VRHE is achieved. These findings demonstrate a sustainable strategy which offers great promise of TiO2 and other oxides to achieve further-improved material properties for broad practical applications.

(Digital Presentation) Resistive Switching and Brain-Inspired Computing in Perovskite Nanowires and Quantum Wires

Abstract: In the past decade, halide perovskites (HPs) have shot to fame in the genre of optoelectronics and photovoltaics owing to their large absorption co-effcient, high color purity, tunable bandgap and long charge diffusion lengths. Besides these traits, HPs also possess innumerable charge transport pathways, inherent hysteresis, high charge-carrier and ionic mobilities which render them as ideal candidates for resistive random access switching memories (RRAMs). However owing to material and electrical instability associated with HP thin-film devices, the figures-of-merits (FOMs) namely retention, endurance and switching speed were not up to the state of-the-art standard until recently. In order to revolutionize HP Re-RAMs we devised a unique device structure where we replaced the thin-film architecture with vertically aligned high density HP nanowires and quantum wires embedded in a porous alumina membrane (PAM) sandwiched between metallic silver and aluminum contacts. The excellent passivation provided by the PAM imparted the requisite electrical and material stability to the environmentally delicate HPs by drastically reducing the surface diffusion pathways and thereby thwarting the moisture induced attacks. Extrapolated retention time as high as 28.3 years and measured device endurance of a million cycles were obtained. Utilizing the single crystalline HP nanowires and quantum wires and their associated high ionic and electronic mobilities, switching speed as fast as 100 ps was also obtained. These FOMs represent record values for HP RRAMs ever reported. Furthermore a 14 nm lateral size HP quantum wire RRAM cell was fabricated and a cross-bar device architecture with a unique sneaky path mitigation scheme were developed, which successfully exhibited the scalability potential of our devices. We further coupled the optoelectronic and switching behaviors and were able to obtain optical programmability among the low resistance states. Besides data storage, the HP nanowires and quantum wires were employed in developing neuromorphic devices enabled with low power and high precision computing capabilities. Specifically, we obtained robust multi-level states in two types of brain-inspired devices capable of performing analog processing tasks by using silver as the top electrode and precisely controlling the current injection in the monocrytalline switching medium and by using indium doped tin oxide as the top electrode and inducing a novel valence change mechanism in the HP nanowires triggering the gradual conductance change. All in all, our nanowire and quantum wire devices propel HP RRAMs to the state-of-the-art standard in multifarious applications concerning future data storage and neuromorphic computing.

(Invited, Digital Presentation) High-Efficiency and Stable Perovskite LEDs and Displays with Nanophotonic Methods

Abstract: Perovskite light-emitting diodes (PeLEDs) have experienced rapid development in the past 8 years. The external quantum efficiencies (EQEs) of red, green, and near-infrared (NIR) PeLEDs have all surpassed the 20% milestone. Meanwhile, the blue PeLEDs also achieved EQEs higher than 10% and are catching up quickly with PeLEDs of other colors. However, there are still two key problems remaining within the PeLEDs for their further development, namely the light extraction problem and the short lifetime problem. Therefore, in this report, we will discuss our recent work targeting addressing the above two critical problems. First, our work on improving the light extraction efficiency by deploying the nanophotonic substrates will be introduced. Second, the improvement of the device’s operational lifetime at high luminance conditions with perovskite nanowires embedded in a porous alumina template will be discussed. Third, a full evaporation method that is compatible with industrialization will be shown. Last but not least, our endeavors on the displays based on perovskite materials will be covered. References [1] Q. Zhang, M. M. Tavakoli, L. Gu, D. Zhang, L. Tang, Y. Gao, J. Guo, Y. Lin, S. -F. Leung, S. Poddar, Y. Fu, Z. Fan, "Efficient metal halide perovskite light-emitting diodes with significantly improved light extraction on nanophotonic substrates," Nature Communications, 10 (1), 727 (2019). [2] Q. Zhang, D. Zhang, L. Gu, S. Poddar, Y. Fu, L. Shu, and Z. Fan, “Three-dimensional perovskite nanophotonic wire array-based light-emitting diodes with significantly improved efficiency and stability,” ACS Nano, 14 (2), 1577-1585 (2020). [3] Y. Fu, Q. Zhang, D. Zhang, Y. Tang, L. Shu, Y. Zhu, and Z. Fan, “Scalable All-evaporation Fabrication of Efficient Light-Emitting Diodes with Hybrid 2D-3D Perovskite Nanostructures,” Advanced Functional Materials, 30, 2002913 (2020). [4] D. Zhang, Q. Zhang, B. Ren, Y. Zhu, M. Abdellah, Y. Fu, B. Cao, C. Wang, L. Gu, Y. Ding, K.-H. Tsui, S. Fan, S. Poddar, L. Shu, Y. Zhang, D.-B. Kuang, J.-F. Liao, Y. Lu, K. Zheng, Z. He, Z. Fan, “Large-scale Planar and Spherical Light-emitting Diodes Based on Arrays of Perovskite Quantum Wires”, Nature Photonics, 19, 284-290 (2022).

(Invited) Biomimetic Eyes with Perovskite Nanowire Array Retina

Abstract: Human eyes are masterpiece of nature, which can realize powerful image sensing with a very concise structure. Biomimetic eyes with characters comparable to human eyes are highly desirable in many technological applications, particularly in the fields of visual prosthesis and machine vision. The World Health Organization reported that globally there are over 252 million people suffering from visual impairment in the year of 2020. This number is exploding due to the prevalence of various mobile devices with small displays. Bionic eyes implantation is one the most effective strategy for vison restoration. However, today, even the most mature bionic eyes have only 300 clinical trials, which is merely 1 ppm of all the visual impaired patients, mainly due to their poor performance and high cost. In addition, industrial applications such as autonomous driving and humanoids also desire cameras with high performance. To achieve biomimetic eyes with imaging performance on a par with human eyes, innovative device structure design and material selection have to be carried out simultaneously. Among all the photosensing material candidates, the ordered one-dimensional (1D) semiconductor nanowire (NW) arrays exhibit unique advantages such as fast carrier transportation and strong light-material interaction due to their anisotropic structure in axial and radial direction, thereby leading to fast response and high responsivity. This presentation focuses on our work on the NW arrays image sensing and can be highlighted as: 1) Controlled growth of well aligned, high-density NW arrays Despite the advantages abovementioned, the integration of NWs has always been a bottleneck challenge hurdling their practical applications. Direct growth of NW arrays can be an effective way to tackle this challenge. We reported for the first time a unique fabrication process to form large-scale, 3D, high-density arrays of lead halide perovskite NWs with well-engineered geometry through a template-assisted growth approach. The array demonstrated amazingly geometry dependent optoelectronic properties and thereby can be used to improve performance of various devices. Particularly, its high regularity leads to the possibility to electrically addressable individual NWs which makes it an ideal candidate for very-large-scale integrated (VLSI) electronics and optoelectronics. The interaction between nanotemplate and sensing materials can introduce unique device performance such as tunable photoresponse and improved stability of perovskites. 2) Assembly of integrated, NW arrays based planar image sensors To demonstrate the technological potency of the NW arrays, we have developed new process to fabricate them into proof-of-concept image sensors. Each image sensor consists of 1,024 photodiode pixels made of vertical perovskite NWs, and the imaging functionality has been verified by recognizing various optical patterns projected onto it. The high density of this NW array and the addressability of individual NW enable this unique image sensor design a potential, extremely high resolution approaching optical diffraction limit. To realize the device assembly, we have developed a PDMS-assisted dry transfer process which can transfer the thin (µm scale) and large-area (cm scale) film onto any substrate without any bubbles and wrinkles. This unique NW manipulation strategy, together with NW geometrical and compositional tunability, may lead to new functionality and inspire novel device design in the future. 3) Invention of a 3D, biomimetic eye with a hemispherical NW array retina The high performance of human eyes originates from the dome shape of retina and the high-density photoreceptors in it. However, the commercial image sensors are dominantly using planar device structures shaped by the mainstream planar microfabrication processes, making it hardly possible for hemispherical device fabrication. In our work, we have developed a novel artificial visual system using a spherical biomimetic electrochemical eye with hemispherical retina made of a high-density perovskite NW array. The device has high similarity to human eyes with part of its photodetection performance superior to human eyes. The hemispherical artificial retina has NW density much higher than that of photoreceptors in a human retina thus can potentially achieve a higher image resolution which is bolstered by implementation of a single-NW ultra-small photodetector. The work may lead to a new generation of photosensing devices based on a bioinspired design that can benefit a wide spectrum of technological applications. In all, with the unique structural properties of NW arrays as the starting point, we realized their controlled growth, developed strategies to manipulate them and designed proper device structures to fully fulfill their advantages. In the future, we will combine them with brains, either biological or digital brains, to explore their applications in fields such as visual prothesis and artificial intelligence. Figure 1