Showing papers by "Zhen Li published in 2016"
TL;DR: In this article, the effect of alloying FA0.85Cs0.15PbI3 with CsPbIsI3 was investigated, and it was shown that the effective tolerance factor can be tuned and the stability of the photoactive α-phase of the mixed solid-state perovskite alloys FA1-xCsxPbisI3 is enhanced.
Abstract: Goldschmidt tolerance factor (t) is an empirical index for predicting stable crystal structures of perovskite materials. A t value between 0.8 and 1.0 is favorable for cubic perovskite structure, and larger (>1) or smaller (<0.8) values of tolerance factor usually result in nonperovskite structures. CH(NH2)2PbI3 (FAPbI3) can exist in the perovskite α-phase (black phase) with good photovoltaic properties. However, it has a large tolerance factor and is more stable in the hexagonal δH-phase (yellow phase), with δH-to-α phase-transition temperature higher than room temperature. On the other hand, CsPbI3 is stabilized to an orthorhombic structure (δO-phase) at room temperature due to its small tolerance factor. We find that, by alloying FAPbI3 with CsPbI3, the effective tolerance factor can be tuned, and the stability of the photoactive α-phase of the mixed solid-state perovskite alloys FA1–xCsxPbI3 is enhanced, which is in agreement with our first-principles calculations. Thin films of the FA0.85Cs0.15PbI3 p...
1,483 citations
TL;DR: A sulfur host that overcomes both obstacles at once for the success of lithium–sulfur batteries by using the polar shells to prevent their outward diffusion and avoids the need for chemically bonding all lithium-polysulfides on the surfaces of polar particles.
Abstract: Lithium-sulfur batteries show advantages for next-generation electrical energy storage due to their high energy density and cost effectiveness. Enhancing the conductivity of the sulfur cathode and moderating the dissolution of lithium polysulfides are two key factors for the success of lithium-sulfur batteries. Here we report a sulfur host that overcomes both obstacles at once. With inherent metallic conductivity and strong adsorption capability for lithium-polysulfides, titanium monoxide@carbon hollow nanospheres can not only generate sufficient electrical contact to the insulating sulfur for high capacity, but also effectively confine lithium-polysulfides for prolonged cycle life. Additionally, the designed composite cathode further maximizes the lithium-polysulfide restriction capability by using the polar shells to prevent their outward diffusion, which avoids the need for chemically bonding all lithium-polysulfides on the surfaces of polar particles.
577 citations
TL;DR: In this paper, the structural advantages of hollow host materials for high-performance Li-S batteries, together with a summary of recent advances in the design and synthesis of various hollow micro-/nanostructures with controlled shapes, tailored shell structures and designed chemical compositions are discussed.
Abstract: Lithium–sulfur (Li–S) batteries have attracted much attention in the field of electrochemical energy storage and conversion. As a vital part of the cathode electrode, the host materials of sulfur usually have a strong impact on the capacity, energy density, cycle life and Coulombic efficiency of Li–S batteries. With their unique physical and chemical properties, the rationally designed hollow nanostructures show conspicuous advantages as sulfur hosts, and have significantly improved the overall performance of Li–S cells. The scope of this review considers the unique structural advantages of hollow host materials for high-performance Li–S batteries, together with a summary of recent advances in the design and synthesis of various hollow micro-/nanostructures with controlled shapes, tailored shell structures and designed chemical compositions. Finally, we propose some emerging requirements of sulfur hosts which we hope will shed some light on the future development trend of hollow structures for advanced Li–S batteries.
556 citations
TL;DR: The hollow CH@LDH polyhedra with complex shell structures not only maximize the advantages of hollow nanostructures for encapsulating a high content of sulfur, but also provide sufficient self-functionalized surfaces for chemically bonding with polysulfides to suppress their outward dissolution.
Abstract: Lithium–sulfur (Li-S) batteries have been considered as a promising candidate for next-generation electrochemical energy-storage technologies because of their overwhelming advantages in energy density. Suppression of the polysulfide dissolution while maintaining a high sulfur utilization is the main challenge for Li–S batteries. Here, we have designed and synthesized double-shelled nanocages with two shells of cobalt hydroxide and layered double hydroxides (CH@LDH) as a conceptually new sulfur host for Li–S batteries. Specifically, the hollow CH@LDH polyhedra with complex shell structures not only maximize the advantages of hollow nanostructures for encapsulating a high content of sulfur (75 wt %), but also provide sufficient self-functionalized surfaces for chemically bonding with polysulfides to suppress their outward dissolution. When evaluated as cathode material for Li–S batteries, the CH@LDH/S composite shows a significantly improved electrochemical performance.
508 citations
TL;DR: This MABr-selective Ostwald ripening process improves cell efficiency but also enhances device stability and thus represents a simple, promising strategy for further improving PSC performance with higher reproducibility and reliability.
Abstract: Organometallic halide perovskite solar cells (PSCs) have shown great promise as a low-cost, high-efficiency photovoltaic technology. Structural and electro-optical properties of the perovskite absorber layer are most critical to device operation characteristics. Here we present a facile fabrication of high-efficiency PSCs based on compact, large-grain, pinhole-free CH3NH3PbI3-xBrx (MAPbI3-xBrx) thin films with high reproducibility. A simple methylammonium bromide (MABr) treatment via spin-coating with a proper MABr concentration converts MAPbI3 thin films with different initial film qualities (for example, grain size and pinholes) to high-quality MAPbI3-xBrx thin films following an Ostwald ripening process, which is strongly affected by MABr concentration and is ineffective when replacing MABr with methylammonium iodide. A higher MABr concentration enhances I-Br anion exchange reaction, yielding poorer device performance. This MABr-selective Ostwald ripening process improves cell efficiency but also enhances device stability and thus represents a simple, promising strategy for further improving PSC performance with higher reproducibility and reliability.
422 citations
TL;DR: Water-soluble and biocompatible PEGylated BP nanoparticles with a high yield were prepared by one-pot solventless high energy mechanical milling technique and exhibit excellent photostability, which makes them suitable as a novel nanotheranostic agent for photoacoustic (PA) imaging and photothermal therapy of cancer.
378 citations
TL;DR: These porous MoS2 tubular structures are constructed from building blocks of ultrathin nanosheets, which are believed to benefit the electrochemical reactions and may inspire new ideas for constructing high-performance electrodes for electrochemical energy storage.
Abstract: Molybdenum disulfide (MoS2), a typical two-dimensional material, is a promising anode material for lithium-ion batteries because it has three times the theoretical capacity of graphite. The main challenges associated with MoS2 anodes are the structural degradation and the low rate capability caused by the low intrinsic electric conductivity and large strain upon cycling. Here, we design hierarchical MoS2 tubular structures internally wired by carbon nanotubes (CNTs) to tackle these problems. These porous MoS2 tubular structures are constructed from building blocks of ultrathin nanosheets, which are believed to benefit the electrochemical reactions. Benefiting from the unique structural and compositional characteristics, these CNT-wired MoS2 tubular structures deliver a very high specific capacity of ~1320 mAh g−1 at a current density of 0.1 A g−1, exceptional rate capability, and an ultralong cycle life of up to 1000 cycles. This work may inspire new ideas for constructing high-performance electrodes for electrochemical energy storage.
351 citations
TL;DR: In this article, the authors investigated the intrinsic instability mechanism of the α-phase at ambient temperature and demonstrated the existence of an anisotropic strained lattice in the (111) plane that drives phase transformation into the δ-phase.
Abstract: Though formamidinium lead triiodide (FAPbI3) possesses a suitable band gap and good thermal stability, the phase transition from the pure black perovskite phase (α-phase) to the undesirable yellow nonperovskite polymorph (δ-phase) at room temperature, especially under humid air, hinders its practical application. Here, we investigate the intrinsic instability mechanism of the α-phase at ambient temperature and demonstrate the existence of an anisotropic strained lattice in the (111) plane that drives phase transformation into the δ-phase. Methylammonium bromide (MABr) alloying (or FAPbI3-MABr) was found to cause lattice contraction, thereby balancing the lattice strain. This led to dramatic improvement in the stability of α-FAPbI3. Solar cells fabricated using FAPbI3-MABr demonstrated significantly enhanced stability under the humid air.
325 citations
TL;DR: It is shown that light-activated transesterification in carbon nanotube dispersed liquid crystalline vitrimers enables flexible design and easy building of dynamic 3D structures out of flat films upon irradiation of light without screws, glues, or molds.
Abstract: Making dynamic three-dimensional (3D) structures capable of reversible shape changes or locomotion purely out of dry polymers is very difficult. Meanwhile, no previous dynamic 3D structures can be remade into new configurations while being resilient to mechanical damages and low temperature. Here, we show that light-activated transesterification in carbon nanotube dispersed liquid crystalline vitrimers enables flexible design and easy building of dynamic 3D structures out of flat films upon irradiation of light without screws, glues, or molds. Shining light also enables dynamic 3D structures to be quickly modified on demand, restored from distortion, repaired if broken, in situ healed when microcrack appears, assembled for more sophisticated structures, reconfigured, and recycled after use. Furthermore, the fabrication, reconfiguration, actuation, reparation, and assembly as well as healing can be performed even at extremely low temperatures (e.g., −130 °C).
298 citations
TL;DR: Ultrasmall PEGylated Cu2-x Se nanoparticles with strong near-infrared absorption have been prepared by an ambient aqueous method and are demonstrated to be a novel nanotheranostic agent for effective deep-tissue photoacoustic imaging, computed tomography imaging, single-photon emission computed tomographic imaging, and photothermal therapy of cancer.
Abstract: Ultrasmall PEGylated Cu2-x Se nanoparticles with strong near-infrared absorption have been prepared by an ambient aqueous method. The resultant water-soluble and biocompatible nanoparticles are demonstrated to be a novel nanotheranostic agent for effective deep-tissue photoacoustic imaging, computed tomography imaging, single-photon emission computed tomography imaging, and photothermal therapy of cancer.
268 citations
TL;DR: Sub 10 nm Bi2S3 biocompatible particles are prepared through a bovine serum albumin (BSA)‐mediated biomineralization process under ambient aqueous conditions and due to the remarkable photothermal conversion efficiency and large X‐ray attenuation coefficient, the implanted tumors are completely eradicated through combined therapies, which highlights the potential of BSA‐capped Bi2NPs as a novel multifunctional nanotheranostic agent.
Abstract: Fabrication of ultrasmall single-component omnipotent nanotheranostic agents integrated with multimodal imaging and multiple therapeutic functions becomes more and more practically relevant but challenging. In this article, sub 10 nm Bi2S3 biocompatible particles are prepared through a bovine serum albumin (BSA)-mediated biomineralization process under ambient aqueous conditions. Owing to the ultrasmall size and colloidal stability, the resulting nanoparticles (NPs) present outstanding blood circulation behavior and excellent tumor targeting ability. Toward theranostic applications, the biosafety profile is carefully investigated. In addition, photothermal conversion is characterized for both photoacoustic imaging and photothermal treatment of cancers. Upon radiolabeling, the performance of the resulting particles for SPECT/CT imaging in vivo is also carried out. Additionally, different combinations of treatments are applied for evaluating the performance of the as-prepared Bi2S3 NPs in photothermal- and radiotherapy of tumors. Due to the remarkable photothermal conversion efficiency and large X-ray attenuation coefficient, the implanted tumors are completely eradicated through combined therapies, which highlights the potential of BSA-capped Bi2S3 NPs as a novel multifunctional nanotheranostic agent.
TL;DR: In this article, the photocatalytic H2 generation and H2O2 disproportionation over g-C3N4 catalysts were investigated and the results showed that the activity of H2 evolution decreased with the increase of H 2O2 concentration; the corresponding AQEs o...
Abstract: Water splitting via two two-electron processes (the H2O first photocatalytically converted to H2 and H2O2 under visible light irradiation and then the H2O2 disproportionation to H2O and O2 by a thermal catalytic process) has attracted extensive attention recently.1,2 Contrary to these reports, we found that not only the photocatalytic H2 generation could be driven by visible light but also the two-electron H2O2 disproportionation to form H2O and O2 could also be photocatalyzed by visible light over g-C3N4 catalysts. Photocatalytic H2, O2 generation, and simultaneous H2O2 formation in Cu/C3N4 and Fe/C3N4 dispersions were confirmed, about 2.1 and 1.4 μmol of H2 and 0.8 and 0.5 μmol of O2 evolved over Cu/C3N4 and Fe/C3N4 in 12 h, respectively. To prove the photocatalytic process of H2O2 disproportionation, the H2O2 was added as a reagent in g-C3N4, Cu/C3N4, and Fe/C3N4 dispersions. The results showed that the activity of H2 evolution decreased with the increase of H2O2 concentration; the corresponding AQEs o...
TL;DR: A new deep learning method that predicts contacts by integrating both evolutionary coupling (EC) and sequence conservation information through an ultra-deep neural network formed by two deep residual neural networks that greatly outperforms existing methods and leads to much more accurate contact-assisted folding.
Abstract: Motivation: Protein contacts contain key information for the understanding of protein structure and function and thus, contact prediction from sequence is an important problem. Recently exciting progress has been made on this problem, but the predicted contacts for proteins without many sequence homologs is still of low quality and not extremely useful for de novo structure prediction. Method: This paper presents a new deep learning method that predicts contacts by integrating both evolutionary coupling (EC) and sequence conservation information through an ultra-deep neural network formed by two deep residual neural networks. The first residual network conducts a series of 1-dimensional convolutional transformation of sequential features; the second residual network conducts a series of 2-dimensional convolutional transformation of pairwise information including output of the first residual network, EC information and pairwise potential. By using very deep residual networks, we can model very complex relationship between sequence and contact map as well as long-range interdependency between contacts and thus, obtain high-quality contact prediction. Results: Our method greatly outperforms existing contact prediction methods and leads to much more accurate contact-assisted protein folding. Tested on the 105 CASP11 targets, 76 CAMEO test proteins and 398 membrane proteins, the average top L long-range prediction accuracy obtained our method, the representative EC method CCMpred and the CASP11 winner MetaPSICOV is 0.47, 0.21 and 0.30, respectively; the average top L/10 long-range accuracy of our method, CCMpred and MetaPSICOV is 0.77, 0.47 and 0.59, respectively. Ab initio folding using our predicted contacts as restraints can yield correct folds (i.e., TMscore>0.6) for 203 of the 579 test proteins, while that using MetaPSICOV- and CCMpred-predicted contacts can do so for only 79 and 62 of them, respectively. Further, our contact-assisted models also have much better quality than template-based models (especially for membrane proteins). Using our predicted contacts as restraints, we can (ab initio) fold 208 of the 398 membrane proteins with TMscore>0.5. By contrast, when the training proteins of our method are used as templates, homology modeling can only do so for 10 of them. One interesting finding is that even if we do not train our prediction models with any membrane proteins, our method works very well on membrane protein contact prediction. In the recent blind CAMEO benchmark, our method successfully folded one mainly-beta protein of 182 residues with a novel fold.
TL;DR: Ultrasmall biocompatible WO3 - x nanodots with an outstanding X-ray radiation sensitization effect are prepared, and demonstrated to be applicable for multi-modality tumor imaging through computed tomography and photoacoustic imaging, and effective cancer treatment combining both photothermal therapy and radiation therapy.
Abstract: Ultrasmall biocompatible WO3 - x nanodots with an outstanding X-ray radiation sensitization effect are prepared, and demonstrated to be applicable for multi-modality tumor imaging through computed tomography and photoacoustic imaging (PAI), and effective cancer treatment combining both photothermal therapy and radiation therapy.
TL;DR: A recent review summarizes the recent progress in the field of blue AIEgens, mainly focusing on design strategies for controlling the intramolecular conjugation effect and to realize blue emission, and also gives some outlooks on the further exploration of this field.
Abstract: As one kind of important emitting material, efficient blue-emitting luminogens are badly needed for perfect commercialization of OLEDs. Limited by their intrinsic wide bandgap and their low efficiency in the solid state, excellent blue luminogens are still scarce. Excitingly, the characteristic of aggregation-induced emission might offer a new opportunity to develop good blue luminogens. This review summarizes the recent progress in the field of blue AIEgens, mainly focusing on design strategies for controlling the intramolecular conjugation effect and to realize blue emission, and also gives some outlooks on the further exploration of this field at the end of this paper.
TL;DR: In this article, two crystalline polymorphs of TMPE, with the space groups P21c and C2, are cultured from different solvent mixtures and display apparent blue fluorescence with the characteristic of aggregation induced emission (AIE).
Abstract: Two crystalline polymorphs of TMPE, with the space groups P21(c) and C2, are cultured from different solvent mixtures and display apparent blue fluorescence with the characteristic of aggregation induced emission (AIE). Excitedly, the P21(c) crystal exhibits easily observed mechanoluminescence (ML), while there is no mechanoluminescence for the C2 crystal. Careful investigation of their crystal structures and three analogues demonstrates that the special molecule packing of TMPE in the P21(c) crystal accounts for its exciting efficient ML performance, providing some information to understand the structure–property relationship of efficient organic ML materials.
TL;DR: In this article, a novel eco-friendly approach involving hydrazine hydrate-assisted hydrothermal cutting followed by functionalization with poly (ethylene imine) (PEI) for fabricating highly fluorescent graphene quantum dots from coffee grounds was developed.
TL;DR: In this article, the performance of a planar perovskite solar cell using a fullerene passivated metal oxide/fullerene electron selective layer (ESL) was investigated.
Abstract: Both tin oxide (SnO2) and fullerenes have been reported as electron selective layers (ESLs) for producing efficient lead halide perovskite solar cells. Here, we report that SnO2 and fullerenes can work cooperatively to further boost the performance of perovskite solar cells. We find that fullerenes can be redissolved during perovskite deposition, allowing ultra-thin fullerenes to be retained at the interface and some dissolved fullerenes infiltrate into perovskite grain boundaries. The SnO2 layer blocks holes effectively; whereas, the fullerenes promote electron transfer and passivate both the SnO2/perovskite interface and perovskite grain boundaries. With careful device optimization, the best-performing planar perovskite solar cell using a fullerene passivated SnO2 ESL has achieved a steady-state efficiency of 17.75% and a power conversion efficiency of 19.12% with an open circuit voltage of 1.12 V, a short-circuit current density of 22.61 mA cm−2, and a fill factor of 75.8% when measured under reverse voltage scanning. We find that the partial dissolving of fullerenes during perovskite deposition is the key for fabricating high-performance perovskite solar cells based on metal oxide/fullerene ESLs.
TL;DR: This work demonstrates the potential of ultrasmall Bi2Se3 nanodots in multimodal imaging-guided synergetic radiophotothermal therapy of cancer and exhibits a high photothermal conversion efficiency.
Abstract: Sub-3 nm ultrasmall Bi2Se3 nanodots stabilized with bovine serum albumin were successfully synthesized through a reaction of hydroxyethylthioselenide with bismuth chloride in aqueous solution under ambient conditions. These nanodots exhibit a high photothermal conversion efficiency (η = 50.7%) due to their strong broad absorbance in the near-infrared (NIR) window and serve as a nanotheranostic agent for photoacoustic imaging and photothermal cancer therapy. In addition, they also display radioenhancement with a ratio of 6% due to their sensitivity to X-rays, which makes them a potential sensitizer for radiotherapy. These nanodots were also labled with radioactive 99mTc for quantification of their biodistribution by single-photon-emission computed tomography (SPECT)/computed tomography (CT) imaging. Our work demonstrates the potential of ultrasmall Bi2Se3 nanodots in multimodal imaging-guided synergetic radiophotothermal therapy of cancer.
08 Oct 2016
TL;DR: Wang et al. as discussed by the authors proposed a Long Short-Term Memorized Context Fusion (LSTM-CF) model that captures and fuses contextual information from multiple channels of photometric and depth data, and incorporated this model into deep CNNs for end-to-end training.
Abstract: Semantic labeling of RGB-D scenes is crucial to many intelligent applications including perceptual robotics. It generates pixelwise and fine-grained label maps from simultaneously sensed photometric (RGB) and depth channels. This paper addresses this problem by (i) developing a novel Long Short-Term Memorized Context Fusion (LSTM-CF) Model that captures and fuses contextual information from multiple channels of photometric and depth data, and (ii) incorporating this model into deep convolutional neural networks (CNNs) for end-to-end training. Specifically, contexts in photometric and depth channels are, respectively, captured by stacking several convolutional layers and a long short-term memory layer; the memory layer encodes both short-range and long-range spatial dependencies in an image along the vertical direction. Another long short-term memorized fusion layer is set up to integrate the contexts along the vertical direction from different channels, and perform bi-directional propagation of the fused vertical contexts along the horizontal direction to obtain true 2D global contexts. At last, the fused contextual representation is concatenated with the convolutional features extracted from the photometric channels in order to improve the accuracy of fine-scale semantic labeling. Our proposed model has set a new state of the art, i.e., \({\mathbf{48.1}}\%\) and \({\mathbf{49.4}}\%\) average class accuracy over 37 categories (\({\mathbf{2.2}}\%\) and \({\mathbf{5.4}}\%\) improvement) on the large-scale SUNRGBD dataset and the NYUDv2 dataset, respectively.
TL;DR: A comprehensive coverage of recent advances in metal chalcogenides and their correlated thermoelectric enhancement mechanisms are provided in this article, with the hope that they can inspire further enhancement of performance.
Abstract: Due to the urgency of our energy and environmental issues, a variety of cost-effective and pollution-free technologies have attracted considerable attention, among which thermoelectric technology has made enormous progress. Substantial numbers of new thermoelectric materials are created with high figure of merit (ZT) by using advanced nanoscience and nanotechnology. This is especially true in the case of metal-chalcogenide-based materials, which possess both relatively high ZT and low cost among all the different kinds of thermoelectric materials. Here, comprehensive coverage of recent advances in metal chalcogenides and their correlated thermoelectric enhancement mechanisms are provided. Several new strategies are summarized with the hope that they can inspire further enhancement of performance, both in metal chalcogenides and in other materials.
TL;DR: In this paper, nonnoble metal cobalt hydroxide nanoparticles [Co(OH)2 NPs] implanted uniformly on graphitic carbon nitride (g-C3N4) as a co-catalyst for hydrogen evolution reaction (HER) by in-situ chemical deposition method were reported.
Abstract: In this work, non-noble metal cobalt hydroxide nanoparticles [Co(OH)2 NPs] implanted uniformly on graphitic carbon nitride (g-C3N4) as a co-catalyst for hydrogen evolution reaction (HER) by in-situ chemical deposition method were reported. After co-sensitized by Eosin Y (EY) and Rose Bengal (RB) dyes, this photocatalyst exhibited a comparatively low onset potential (0.26 V) for HER and high photocatalytic HER activity under visible light irradiation. The g-C3N4 not only provided a large area and nanoporous structure for the confined growth of Co(OH)2 NPs, but also greatly facilitated EY and RB (ER) molecules assembling on its surface, which promoted the charge transfer from dye to co-catalyst. The PL spectra and lifetime test showed the strong interaction between Co(OH)2 NPs and g-C3N4 could enhance the transferr rate of the photogenerated electron to reduce the carries recombination. About 431.9 μmol of hydrogen generated over ER co-sensitized Co(OH)2/C3N4 in 3 h. The apparent quantum efficiencies (AQE) of 29.6 and 27.3% were achieved at 520 nm and 550 nm over Co(OH)2/C3N4, respectively. In addition, this co-sensitized photocatalyst showed satisfied stability for HER, no remarkable decay of activity was observed in 900 min reaction. These results imply that Co(OH)2 is a stable and efficient cheaper co-catalyst for photo-HER.
TL;DR: This work presents a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution, and finds that thePerovskites layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aProtic Solvents and Pb2+ cations.
Abstract: Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.
TL;DR: The multifunctional NIR-responsive platform demonstrates excellent performance in capture and site-release of CTCs with high viability, which provides a robust and versatile means toward individualized antitumor therapies and also shows promising potential for dynamically manipulating cell-substrate interactions in vitro.
Abstract: Isolation of single circulating tumor cells (CTCs) from patients is a very challenging technique that may promote the process of individualized antitumor therapies. However, there exist few systems capable of highly efficient capture and release of single CTCs with high viability for downstream analysis and culture. Herein, we designed a near-infrared (NIR) light-responsive substrate for highly efficient immunocapture and biocompatible site-release of CTCs by a combination of the photothermal effect of gold nanorods (GNRs) and a thermoresponsive hydrogel. The substrate was fabricated by imprinting target cancer cells on a GNR-pre-embedded gelatin hydrogel. Micro/nanostructures generated by cell imprinting produce artificial receptors for cancer cells to improve capture efficiency. Temperature-responsive gelatin dissolves rapidly at 37 °C; this allows bulk recovery of captured CTCs at physiological temperature or site-specific release of single CTCs by NIR-mediated photothermal activation of embedded GNRs....
TL;DR: Unlike normal ACQ-to-AIE conversion by the introduction of aromatic rotors accompanying the realization of a twisted conformation and a prolonged π-system, in this communication, the adjustment of the flexible chains can reach this point with the tunable packing modes while the original ρ-system core and related properties of the aromatic naphthalene diimide remain nearly unchanged, providing an alternative approach for the inhibition of unwantedπ-π stacking.
TL;DR: Improvements benefit from the quasi-open space provided by the interlayer configuration for the diffused sulfur species, which can largely relieve the loss of active substances caused by the volume effect during the lithiation/delithiation process.
Abstract: The ithium–sulfur battery stands as one of the most promising successors of traditional lithium-ion batteries due to its super high theoretical energy density, but practical application still suffers from the shuttle effect arising from soluble intermediate polysulfides. Here, we report SnO2 as a chemical adsorbent for polysulfides. As an interlayer between the cathode and separator, SnO2 gives better results to prevent the polysulfides from diffusing to the lithium anode than as a modifier of the carbon matrix directly. The lithium–sulfur battery with an SnO2 interlayer delivers an initial reversible capacity of 996 mA h g−1 and retains 832 mA h g−1 at the 100th discharge at 0.5 C, with a fading rate of only 0.19% per cycle. The improvements benefit from the quasi-open space provided by the interlayer configuration for the diffused sulfur species, which can largely relieve the loss of active substances caused by the volume effect during the lithiation/delithiation process.
TL;DR: Simple dip-coating transforms thermally responsive shape memory polymers into photo-responsive materials and allows for shape engineering and surface functionalization.
Abstract: Photo-active shape memory polymers (SMPs) are considered as a promising candidate for converting light into mechanical energy. However, most known SMPs are only thermo-responsive. To achieve photo-activity, photo-responsive choromophores or fillers usually have to be incorporated from the very beginning of the material synthesis. Here, we introduce a novel post-synthesis approach to endow normal SMPs with photo-active properties using mussel-inspired surface chemistry. Without changing the original properties, the resultant polydopamine (PDA) coated SMPs show an efficient photo-active performance. The coating can be easily patterned and erased, which allows flexible light-triggered 3-D shape deformation of a planar SMP sheet. Moreover, owing to the high chemical activity, the PDA coating also provides a platform to optimize the surface properties of the photo-responsive SMPs through secondary surface modification.
TL;DR: In this paper, temperature-dependent polarization, dielectric, and impedance spectroscopies of methylammonium lead iodide (MAPbI3) thin film were investigated and no evidence of ferroelectric effect was found in normal operating conditions.
Abstract: Researchers have debated whether methylammonium lead iodide (MAPbI3), with a perovskite crystal structure, is ferroelectric and therefore contributes to the current–voltage hysteresis commonly observed in hybrid perovskite solar cells (PSCs). We thoroughly investigated temperature-dependent polarization, dielectric, and impedance spectroscopies, and we found no evidence of ferroelectric effect in a MAPbI3 thin film at normal operating conditions. Therefore, the effect does not contribute to the hysteresis in PSCs, whereas the large component of ionic migration observed may play a critical role. Our temperature-based polarization and dielectric studies find that MAPbI3 exhibits different electrical behaviors below and above ca. 45 °C, suggesting a phase transition around this temperature. In particular, we report the activation energies of ionic migration for the two phases and temperature-dependent permittivity of MAPbI3. This study contributes to the understanding of the material properties and device pe...
TL;DR: In this article, a far-red emissive (650 nm) two-photon (TP) excitable NRNO probe, using Nile Red as the TP fluorophore, was developed for NO detection and imaging both in vitro and in vivo.
Abstract: As a pivotal signalling molecule involved in various physiological and pathological processes, nitric oxide (NO) has motivated increasing interest in the last few decades. Although a considerable number of fluorescent probes have been developed for NO imaging, the in situ tracking of this gas molecule in biological events remains a big challenge, mainly because of the relatively short excitation and/or emission wavelengths, which are subject to background interference and lowered collection efficiency in deep-tissue imaging. Herein, we report a far-red emissive (650 nm) two-photon (TP) excitable NRNO probe, using Nile Red as the TP fluorophore, for NO detection and imaging both in vitro and in vivo. The NRNO probe shows a fast (within 180 s) and specific fluorescence response toward NO with a limit of detection (LOD) as low as 46 nM. The excellent properties of NRNO enable it to sensitively detect both exogenously and endogenously generated NO in living cells. The “NIR in” and “far-red out” lights lead to improved penetrating ability, thus endowing the probe with high resolution for the illumination of deep tissues. It is therefore able to visualize the NO generation in a lipopolysaccharide (LPS)-mediated inflammation process for the first time. Our results demonstrate that NRNO could be a practical tool for studying the NO-related biological events. Moreover, this study also suggests the possibility of using Nile Red and its derivatives to develop far-red emissive TP probes, which is an important, yet undeveloped area.
TL;DR: In this article, complex refractive index and dielectric function spectra of organic-inorganic lead halide perovskite alloy thin films are presented, together with the critical point parameter analysis (energy and broadening) of the respective composition.
Abstract: Complex refractive index and dielectric function spectra of organic–inorganic lead halide perovskite alloy thin films are presented, together with the critical-point parameter analysis (energy and broadening) of the respective composition. Thin films of methylammonium lead halide alloys (MAPbI3, MAPbBr3, MAPbBr2I, and MAPbBrI2), formamidinium lead halide alloys (FAPbI3, FAPbBr3, and FAPbBr2I), and formamidinium cesium lead halide alloys [FA0.85Cs0.15PbI3, FA0.85Cs0.15PbBrI2, and FA0.85Cs0.15Pb(Br0.4I0.6)3] were studied. The complex refractive index and dielectric functions were determined by spectroscopic ellipsometry (SE) in the photon energy range of 0.7–6.5 eV. Critical point energies and optical transitions were obtained by lineshape fitting to the second-derivative of the complex dielectric function data of these thin films as a function of alloy composition. Absorption onset in the vicinity of the bandgap, as well as critical point energies and optical band transition shift toward higher energies as the concentration of Br in the films increases. Cation alloying (Cs+) has less effect on the optical properties of the thin films compared to halide mixed alloys. The reported optical properties can help to understand the fundamental properties of the perovskite materials and also be used for optimizing or designing new devices.