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Showing papers by "Yang Yang published in 2015"



Journal ArticleDOI
TL;DR: In this paper, the authors review the organic-inorganic hybrid halide perovskite and delve into its recent progress and relevant applications, highlighting its exceptional attributes including high carrier mobility, an adjustable spectral absorption range, long diffusion lengths, and the simplicity and affordability of fabrication.

867 citations


Journal ArticleDOI
TL;DR: Electrical properties of this modified interfacial layer strongly suggests that PCBB-2CN-2C8 passivates the TiO2 surface and thus reduces charge recombination loss caused by the deep trap states ofTiO2.
Abstract: In perovskite based planar heterojunction solar cells, the interface between the TiO2 compact layer and the perovskite film is critical for high photovoltaic performance. The deep trap states on the TiO2 surface induce several challenging issues, such as charge recombination loss and poor stability etc. To solve the problems, we synthesized a triblock fullerene derivative (PCBB-2CN-2C8) via rational molecular design for interface engineering in the perovskite solar cells. Modifying the TiO2 surface with the compound significantly improves charge extraction from the perovskite layer. Together with its uplifted surface work function, open circuit voltage and fill factor are dramatically increased from 0.99 to 1.06 V, and from 72.2% to 79.1%, respectively, resulting in 20.7% improvement in power conversion efficiency for the best performing devices. Scrutinizing the electrical properties of this modified interfacial layer strongly suggests that PCBB-2CN-2C8 passivates the TiO2 surface and thus reduces charge recombination loss caused by the deep trap states of TiO2. The passivation effect is further proven by stability testing of the perovskite solar cells with shelf lifetime under ambient conditions improved by a factor of more than 4, from ∼40 h to ∼200 h, using PCBB-2CN-2C8 as the TiO2 modification layer. This work offers not only a promising material for cathode interface engineering, but also provides a viable approach to address the challenges of deep trap states on TiO2 surface in planar perovskite solar cells.

483 citations


Journal ArticleDOI
TL;DR: In this paper, the use of carefully selected multiple donor polymers is shown to improve the performance of polysilicon solar cells, and the performance was further improved by selecting carefully selected polymers.
Abstract: The use of carefully selected multiple donor polymers is shown to improve the performance of polymer solar cells.

482 citations


Journal ArticleDOI
TL;DR: An effective strategy to investigate the role of the extrinsic ion in the context of optoelectronic properties, in which the morphological factors that closely correlate to device performance are mostly decoupled is reported.
Abstract: Perovskite photovoltaics offer a compelling combination of extremely low-cost, ease of processing and high device performance. The optoelectronic properties of the prototypical CH3NH3PbI3 can be further adjusted by introducing other extrinsic ions. Specifically, chlorine incorporation has been shown to affect the morphological development of perovksite films, which results in improved optoelectronic characteristics for high efficiency. However, it requires a deep understanding to the role of extrinsic halide, especially in the absence of unpredictable morphological influence during film growth. Here we report an effective strategy to investigate the role of the extrinsic ion in the context of optoelectronic properties, in which the morphological factors that closely correlate to device performance are mostly decoupled. The chlorine incorporation is found to mainly improve the carrier transport across the heterojunction interfaces, rather than within the perovskite crystals. Further optimization according this protocol leads to solar cells achieving power conversion efficiency of 17.91%.

411 citations


Journal ArticleDOI
TL;DR: A fast interfacial recombination at the interface of CH3NH3PbI3/electron selective contact layer (mesoporous TiO2), occurring in millisecond domains, is the critical issue for charge carrier recombination loss.
Abstract: In this study, we communicate an investigation on efficient CH3NH3PbI3-based solar cells with carbon electrode using mesoporous TiO2 and NiO layers as electron and hole selective contacts. The device possesses an appreciated power conversion efficiency of 14.9% under AM 1.5G illumination. The detailed information can be disclosed with impedance spectroscopy via tuning the interfaces between CH3NH3PbI3 and different charge selective contacts. The results clearly show charge accumulation at the interface of CH3NH3PbI3. The NiO is believed to efficiently accelerate charge extraction to the external circuit. The extracted charge could improve photovoltaic performance by shifting hole Fermi level down, achieving a high device photovoltage. A fast interfacial recombination at the interface of CH3NH3PbI3/electron selective contact layer (mesoporous TiO2), occurring in millisecond domains, is the critical issue for charge carrier recombination loss.

400 citations


Journal ArticleDOI
TL;DR: In this article, the current status of CH3NH3PbX3 (X = I, Br, Cl) based photovoltaic devices and their properties are discussed.
Abstract: Perovskite solar cells have received considerable attention in recent years as a promising material capable of developing high performance photovoltaic devices at a low cost. Their high absorption coefficient, tunable band gap, low temperature processing and abundant elemental constituents provide numerous advantages over most thin film absorber materials. In this review, we discuss the current status of CH3NH3PbX3 (X = I, Br, Cl) based photovoltaic devices and provide a comprehensive review of CH3NH3PbX3 device structures, film properties, fabrication methods, and photovoltaic performance. We emphasize the importance of perovskite film formation and properties in achieving highly efficient photovoltaic devices. The flexibility and simplicity of perovskite fabrication methods allow use of mesoporous and planar device architectures. A variety of processing techniques are currently employed to form the highest quality CH3NH3PbX3 films that include precursor modifications, thermal annealing and post-deposition treatments. Here we outline and discuss the resulting material qualities and device performances. Suggestions regarding needed improvements and future research directions are provided based on the current field of available literature.

384 citations


Journal ArticleDOI
TL;DR: The defect energy distribution in the CH3NH3PbI3 perovskite is characterized and identified using admittance spectroscopy, which reveals a deep defect state ∼0.16 eV above the valence band.
Abstract: Thin film photovoltaic cells based on hybrid halide perovskite absorbers have emerged as promising candidates for next generation photovoltaics. Here, we have characterized and identified the defect energy distribution in the CH3NH3PbI3 perovskite using admittance spectroscopy, which reveals a deep defect state ∼0.16 eV above the valence band. According to theoretical calculations, the defect state is possibly attributed to iodine interstitials (Ii), which can become the non-radiative recombination centers in the absorber.

327 citations


Journal ArticleDOI
TL;DR: In this paper, a dopant-free donor-acceptor (D-A) conjugated small molecule was used as a hole transport material for planar perovskite solar cells.
Abstract: We demonstrate efficient planar perovskite solar cells using a dopant-free donor–acceptor (D–A) conjugated small molecule as a hole transport material. The photovoltaic cell reaches a power conversion efficiency (PCE) of 14.9%, which is comparable to or even better than that of the devices using the traditional doped 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) hole transport material under equivalent conditions. We ascribe the high performance to the excellent charge transporting properties of the D–A conjugated small molecule. Time-resolved photoluminescence (PL), transient photocurrent response, and impedance spectroscopy characterization indicate that this D–A conjugated small molecule plays a key role in hole collection and extraction in perovskite based photovoltaic devices. The dopant-free D–A small molecule hole transport material used here not only improves the efficiency, but also facilitates the fabrication process and thus potentially reduces the fabrication cost of perovskite solar cells.

207 citations


Journal ArticleDOI
04 Jun 2015-Oncogene
TL;DR: It is shown that H19 depletion impairs, whereas its overexpression enhances the motility and invasiveness of tumor cells, and that the anti-diabetic drug metformin inhibits tumor cell migration and invasion, partly by downregulating H19 via DNA methylation.
Abstract: The imprinted, developmentally regulated H19 long noncoding RNA has been implicated in the pathogenesis of diverse human cancers, but the underlying mechanisms have remained poorly understood. Here, we report that H19 promotes tumor cell migration and invasion by inhibiting let-7, a potent tumor suppressor microRNA that functions to posttranscriptionally suppress the expression of oncogenes that regulate cell growth and motility. We show that H19 depletion impairs, whereas its overexpression enhances the motility and invasiveness of tumor cells. These phenomena occur, at least in part through affecting let-7-mediated regulation of metastasis-promoting genes, including Hmga2, c-Myc and Igf2bp3. This H19/let-7-dependent regulation is recapitulated in vivo where co-expressions of oncogenes and H19 exist in both primary human ovarian and endometrial cancers. Furthermore, we provide evidence that the anti-diabetic drug metformin inhibits tumor cell migration and invasion, partly by downregulating H19 via DNA methylation. Our results reveal a novel mechanism underpinning H19-mediated regulation in metastasis and may explain why in some cases increased let-7 expression unexpectedly correlates with poor prognosis, given the widely accepted role for let-7 as a tumor suppressor. Targeting this newly identified pathway might offer therapeutic opportunities.

181 citations


Journal ArticleDOI
Qi Li1, Yi Jia1, Luru Dai, Yang Yang, Junbai Li1 
13 Mar 2015-ACS Nano
TL;DR: Characterization of a single FF microrod indicates that the FFmicrorod can act as an active optical waveguide material, allowing locally excited photoluminescence to propagate along the length of the micRORod with coupling out at the microrods tips.
Abstract: Diphenylalanine (FF) microrods were obtained by manipulating the fabrication conditions. Fourier transform infrared (FTIR), circular dichroism (CD), fluorescence (FL) spectroscopy, and X-ray diffraction (XRD) measurements revealed the molecular arrangement within the FF microrods, demonstrating similar secondary structure and molecular arrangement within FF microtubes and nanofibers. Accordingly, a possible mechanism was proposed, which may provide important guidance on the design and assembly manipulation of peptides and other biomolecules. Furthermore, characterization of a single FF microrod indicates that the FF microrod can act as an active optical waveguide material, allowing locally excited photoluminescence to propagate along the length of the microrod with coupling out at the microrod tips.

Journal ArticleDOI
TL;DR: The novel method developed in this work for the synthesis of functional hybrid materials can be extended to the preparation of various MOFs-derived functional nanocomposites owing to the versatility of links and metal centers in MOFs.
Abstract: Iron oxides are extensively investigated as anode materials for lithium-ion batteries (LIBs) because of their large specific capacities. However, they undergo huge volume changes during cycling that result in anode pulverization and loss of electrical connectivity. As a result, the capacity retention of the iron oxide anodes is poor and should be improved for commercial applications. Herein, we report the preparation of ultrasmall Fe2O3 nanoparticles embedded in nitrogen-doped hollow carbon sphere shells (Fe2O3@N-C) by the direct pyrolysis of Fe-based zeolitic imidazolate frameworks (Fe-ZIF) at 620 °C in air. As an anode material for LIBs, the capacity retained was 1573 mA h g−1 after 50 cycles at a current density of 0.1 C (1 C = 1000 mA g−1). Even undergoing the high-rate capability test twice, it can still deliver a remarkably reversible and stable capacity of 1142 mA h g−1 after 100 cycles at a current density of 1 C. The excellent electrochemical performance is attributed to the unique structure of ultrasmall Fe2O3 nanoparticles uniformly distributed in the shell of nitrogen-doped carbon spheres, which simultaneously solve the major problems of pulverization, facilitate rapid electrochemical kinetics, and effectively avoid the aggregation of Fe2O3 nanoparticles during de/lithiation. The novel method developed in this work for the synthesis of functional hybrid materials can be extended to the preparation of various MOFs-derived functional nanocomposites owing to the versatility of links and metal centers in MOFs.

Journal ArticleDOI
26 Jun 2015-ACS Nano
TL;DR: A multilayer transparent top electrode for perovskite photovoltaic devices delivering an 11.5% efficiency in top illumination mode is developed, based on a dielectric/metal/dielectric structure, featuring an ultrathin gold seeded silver layer.
Abstract: Halide perovskites (PVSK) have attracted much attention in recent years due to their high potential as a next generation solar cell material. To further improve perovskites progress toward a state-of-the-art technology, it is desirable to create a tandem structure in which perovskite may be stacked with a current prevailing solar cell such as silicon (Si) or Cu(In,Ga)(Se,S)2 (CIGS). The transparent top electrode is one of the key components as well as challenges to realize such tandem structure. Herein, we develop a multilayer transparent top electrode for perovskite photovoltaic devices delivering an 11.5% efficiency in top illumination mode. The transparent electrode is based on a dielectric/metal/dielectric structure, featuring an ultrathin gold seeded silver layer. A four terminal tandem solar cell employing solution processed CIGS and perovskite cells is also demonstrated with over 15% efficiency.

Posted Content
TL;DR: As key contributions, user pause probability, user arrival, and departure probabilities are derived in this paper for evaluating the user mobility performance in a hotspot-type 5G small cell network.
Abstract: With small cell networks becoming core parts of the fifth generation (5G) cellular networks, it is an important problem to evaluate the impact of user mobility on 5G small cell networks. However, the tendency and clustering habits in human activities have not been considered in traditional user mobility models. In this paper, human tendency and clustering behaviors are first considered to evaluate the user mobility performance for 5G small cell networks based on individual mobility model (IMM). As key contributions, user pause probability, user arrival and departure probabilities are derived in this paper for evaluat-ing the user mobility performance in a hotspot-type 5G small cell network. Furthermore, coverage probabilities of small cell and macro cell BSs are derived for all users in 5G small cell networks, respectively. Compared with the traditional random waypoint (RWP) model, IMM provides a different viewpoint to investigate the impact of human tendency and clustering behaviors on the performance of 5G small cell networks.

Journal ArticleDOI
TL;DR: In this paper, a monolithic integration of perovskite and polymer subcells into a tandem structure is realized through a full solution process, where a small molecule additive, BmPyPhB, is added into the precursor solution to improve the uniformity of the initial nucleation process of the crystal by providing heterogeneous nucleation sites throughout the solution space.
Abstract: In the current study, a monolithic integration of perovskite and polymer subcells into a tandem structure is realized through a full solution process. The wide bandgap perovskite absorber (CH3NH3PbI3) is processed via a one-step deposition employing an additive-assisted solvent wash method. In particular, a small molecule additive, BmPyPhB, is added into the precursor solution to improve the uniformity of the initial nucleation process of the crystal by providing heterogeneous nucleation sites throughout the solution space. Next, a solvent wash method is employed to induce the fast crystallization of uniform and well-defined grains in the absorber layer as well as to reduce the requirement for thermal annealing. Thus, the highest power conversion efficiency (PCE) of 9.1% is obtained for a single junction, planar-structured CH3NH3PbI3 solar cell. For the polymer absorber, a new IR-sensitive block copolymer, PBSeDTEG8, with photosensitivity up to 950 nm is utilized to broaden the photoresponse of the tandem solar cell. More importantly, this polymer:PCBM blend exhibits improved thermal stability, which can endure thermal annealing process while fabricating the perovskite subcell. Subsequently, this hybrid tandem solar cell based on perovskite/polymer subcells achieves the highest efficiency of 10.2%.

Journal ArticleDOI
01 Apr 2015-ACS Nano
TL;DR: The ultrathin In2O3 enables construction of highly sensitive and selective biosensors through immobilization of specific aptamers to the channel surface; the ability to detect subnanomolar concentrations of dopamine is demonstrated.
Abstract: We demonstrate straightforward fabrication of highly sensitive biosensor arrays based on field-effect transistors, using an efficient high-throughput, large-area patterning process. Chemical lift-off lithography is used to construct field-effect transistor arrays with high spatial precision suitable for the fabrication of both micrometer- and nanometer-scale devices. Sol-gel processing is used to deposit ultrathin (∼4 nm) In2O3 films as semiconducting channel layers. The aqueous sol-gel process produces uniform In2O3 coatings with thicknesses of a few nanometers over large areas through simple spin-coating, and only low-temperature thermal annealing of the coatings is required. The ultrathin In2O3 enables construction of highly sensitive and selective biosensors through immobilization of specific aptamers to the channel surface; the ability to detect subnanomolar concentrations of dopamine is demonstrated.

Journal ArticleDOI
TL;DR: The result suggests that the HTL in traditional perovskite solar cell, even with good light absorption capability, cannot contribute to the overall device photocurrent, unless this HTL becomes a BHJ layer (by adding electron transporting material like PC71BM).
Abstract: We successfully demonstrated an integrated perovskite/bulk-heterojunction (BHJ) photovoltaic device for efficient light harvesting and energy conversion. Our device efficiently integrated two photovoltaic layers, namely a perovskite film and organic BHJ film, into the device. The device structure is ITO/TiO2/perovskite/BHJ/MoO3/Ag. A wide bandgap small molecule DOR3T-TBDT was used as donor in the BHJ film, and a power conversion efficiency (PCE) of 14.3% was achieved in the integrated device with a high short circuit current density (JSC) of 21.2 mA cm–2. The higher JSC as compared to that of the traditional perovskite/HTL (hole transporting layer) device (19.3 mA cm–2) indicates that the BHJ film absorbs light and contributes to the current density of the device. Our result further suggests that the HTL in traditional perovskite solar cell, even with good light absorption capability, cannot contribute to the overall device photocurrent, unless this HTL becomes a BHJ layer (by adding electron transporting...

Journal ArticleDOI
TL;DR: Modified 3,4-ethylenedioxythiophene is employed as the conjugation side chain in conjugated polymers, which can significantly depress the dark current of the polymer photodetectors with little associated decrease in photovoltaic properties, thus enhanceing the detectivities.
Abstract: Modified 3,4-ethylenedioxythiophene is employed as the conjugated side chain in conjugated polymers, which can significantly depress the dark current of the polymer photodetectors with little associated decrease in photovoltaic properties, thus enhanceing the detectivities. This approach can be applied to a variety of conjugated polymers covering a photoresponse range from UV to NIR.

Journal ArticleDOI
TL;DR: The considerably reduced persistent photocurrent effect of In-Ga-Zn-O (IGZO)-based hybrid phototransistors is first demonstrated via an organic-inorganic bilayer approach.
Abstract: The creation of new organic-inorganic phototransistors with high and broad spectral photosensitivity is reported. The extended charge transport and photoconductivity between the layers in the bilayer structure results in a notable detectivity of over 10(12) Jones and a linear dynamic range of over 100 dB at a broad spectral bandwidth across the UV-NIR range. Furthermore, the considerably reduced persistent photocurrent effect of In-Ga-Zn-O (IGZO)-based hybrid phototransistors is first demonstrated via an organic-inorganic bilayer approach.

Journal ArticleDOI
29 Oct 2015-ACS Nano
TL;DR: The conformal ultrathin field-effect transistor biosensors developed here offer new opportunities for future wearable human technologies.
Abstract: Conformal bioelectronics enable wearable, noninvasive, and health-monitoring platforms. We demonstrate a simple and straightforward method for producing thin, sensitive In2O3-based conformal biosensors based on field-effect transistors using facile solution-based processing. One-step coating via aqueous In2O3 solution resulted in ultrathin (3.5 nm), high-density, uniform films over large areas. Conformal In2O3-based biosensors on ultrathin polyimide films displayed good device performance, low mechanical stress, and highly conformal contact determined using polydimethylsiloxane artificial skin having complex curvilinear surfaces or an artificial eye. Immobilized In2O3 field-effect transistors with self-assembled monolayers of NH2-terminated silanes functioned as pH sensors. Functionalization with glucose oxidase enabled d-glucose detection at physiologically relevant levels. The conformal ultrathin field-effect transistor biosensors developed here offer new opportunities for future wearable human technologies.

Journal ArticleDOI
TL;DR: These key findings not only demonstrated a general and effective method to improve the thermal and chemical stabilities of metal nanowire networks but also provided a basic guideline toward rational design of highly efficient and robust composite electrodes.
Abstract: Solution-processed silver nanowire networks are one of the promising candidates to replace a traditional indium tin oxide as next-generation transparent and flexible electrodes due to their ease of processing, moderate flexibility, high transparency, and low sheet resistance. To date, however, high stability of the nanowire networks remains a major challenge because the long-term usages of these electrodes are limited by their poor thermal and chemical stabilities. Existing methods for addressing this challenge mainly focus on protecting the nanowire network with additional layers that require vacuum processes, which can lead to an increment in manufacturing cost. Here, we report a straightforward strategy of a sol–gel processing as a fast and robust way to improve the stabilities of silver nanowires. Compared with reported nanoparticles embedded in nanowire networks, better thermal and chemical stabilities are achieved via sol–gel coating of TiO2 over the silver nanowire networks. The conformal surface c...

Journal ArticleDOI
Leszek Adamczyk1, J. K. Adkins2, G. Agakishiev3, Madan M. Aggarwal4  +353 moreInstitutions (53)
TL;DR: The measured asymmetries provide evidence at the 3σ level for positive gluon polarization in the Bjorken-x region x>0.05 and place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep-inelastic scattering (DIS), semi-inclusive DIS, and RHIC pp data.
Abstract: We report a new measurement of the midrapidity inclusive jet longitudinal double-spin asymmetry, A_{LL}, in polarized pp collisions at center-of-mass energy sqrt[s]=200 GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep-inelastic scattering (DIS), semi-inclusive DIS, and RHIC pp data. The measured asymmetries provide evidence at the 3σ level for positive gluon polarization in the Bjorken-x region x>0.05.

Journal ArticleDOI
TL;DR: In this article, the authors developed a facile and quantitative method to improve the electron transport properties and resulting device performances of perovskite solar cells based on post-incorporation of various acetylacetonate additives.
Abstract: We developed a facile and quantitative method to improve the electron transport properties and resulting device performances of perovskite solar cells based on post-incorporation of various acetylacetonate additives. Previous studies rely on synthesis or soaking processes with limited additive control. Here, our acetylacetonated-based additives are used as effective intermediate gels to interact with TiO2 nanocrystals using a simple approach. The incorporation process can be controlled effectively and quantitatively using a range of additives from divalent (II), trivalent (III), and tetravalent (IV) to hexavalent (VI) acetylacetonate. Electronic parameters of solar cell devices, such as short circuit current (Jsc) and fill factor (FF), are enhanced, regardless of the different valencies of the additives. Zirconium(IV) acetylacetonate was found to be the most effective additive, with average PCE improved from 15.0% to 15.8%. Detailed characterization experiments including transient photoluminescence spectra, ultra-violet photoelectron spectroscopy, photovoltage decay, and photocurrent decay indicate an improved interface with improved carrier extraction originating from the TiO2 modification.

Journal ArticleDOI
Nan Li1, Yong Chen1, Ying-Ming Zhang1, Yang Yang1, Yue Su1, Jiatong Chen1, Yu Liu1 
TL;DR: Taking the anticancer drug DOX as an example, cell viability experiments revealed that the DOX@HACD-AuNPs system exhibited similar tumor cell inhibition abilities but lower toxicity than free DOX due to the hyaluronic acid reporter-mediated endocytosis, indicating great potential for the targeted delivery of anticancer drugs.
Abstract: Through the high affinity of the β-cyclodextrin (β-CD) cavity for adamantane moieties, novel polysaccharide-gold nanocluster supramolecular conjugates (HACD-AuNPs) were successfully constructed from gold nanoparticles (AuNPs) bearing adamantane moieties and cyclodextrin-grafted hyaluronic acid (HACD). Due to their porous structure, the supramolecular conjugates could serve as a versatile and biocompatible platform for the loading and delivery of various anticancer drugs, such as doxorubicin hydrochloride (DOX), paclitaxel (PTX), camptothecin (CPT), irinotecan hydrochloride (CPT-11), and topotecan hydrochloride (TPT), by taking advantage of the controlled association/dissociation of drug molecules from the cavities formed by the HACD skeletons and AuNPs cores as well as by harnessing the efficient targeting of cancer cells by hyaluronic acid. Significantly, the release of anticancer drugs from the drug@HACD-AuNPs system was pH-responsive, with more efficient release occurring under a mildly acidic environment, such as that in a cancer cell. Taking the anticancer drug DOX as an example, cell viability experiments revealed that the DOX@HACD-AuNPs system exhibited similar tumor cell inhibition abilities but lower toxicity than free DOX due to the hyaluronic acid reporter-mediated endocytosis. Therefore, the HACD-AuNPs supramolecular conjugates may possess great potential for the targeted delivery of anticancer drugs.

Journal ArticleDOI
Leszek Adamczyk1, J. K. Adkins2, G. Agakishiev3, Madan M. Aggarwal4  +343 moreInstitutions (53)
TL;DR: In this paper, Lambda Lambda correlation measurements in heavy-ion collisions for Au + Au collisions at root s(NN) = 200 GeV using the STAR experiment at the Relativistic Heavy-Ion Collider are presented.
Abstract: We present Lambda Lambda correlation measurements in heavy-ion collisions for Au + Au collisions at root s(NN) = 200 GeV using the STAR experiment at the Relativistic Heavy-Ion Collider. The Lednicky-Lyuboshitz analytical model has been used to fit the data to obtain a source size, a scattering length and an effective range. Implications of the measurement of the Lambda Lambda correlation function and interaction parameters for dihyperon searches are discussed.

Journal ArticleDOI
TL;DR: The combined application of these pcCPP and NGR modifications may provide a reasonable approach for the selectively targeted delivery of siRNA in tumor tissues.

Journal ArticleDOI
Leszek Adamczyk1, J. K. Adkins2, G. Agakishiev3, Madan M. Aggarwal4  +324 moreInstitutions (48)
TL;DR: In this article, the authors report on measurements of dielectron (e(+) e(-)) production in Au + Au collisions at a center-of-mass energy of 200 GeV per nucleon-nucleon pair using the STAR detector at BNL Relativistic Heavy Ion Collider.
Abstract: We report on measurements of dielectron (e(+) e(-)) production in Au + Au collisions at a center-of-mass energy of 200 GeV per nucleon-nucleon pair using the STAR detector at BNL Relativistic Heavy Ion Collider. Systematic measurements of the dielectron yield as a function of transverse momentum (p(T)) and collision centrality show an enhancement compared to a cocktail simulation of hadronic sources in the low invariant-mass region (M-ee < 1 GeV / c(2)). This enhancement cannot be reproduced by the rho-meson vacuum spectral function. In minimum-bias collisions, in the invariant-mass range of 0.30-0.76 GeV / c(2), integrated over the full pT acceptance, the enhancement factor is 1.76 +/- 0.06 (stat.) +/- 0.26 (sys.) +/- 0.29 (cocktail). The enhancement factor exhibits weak centrality and pT dependence in STAR's accessible kinematic regions, while the excess yield in this invariant-mass region as a function of the number of participating nucleons follows a power-law shape with a power of 1.44 +/- 0.10. Models that assume an in-medium broadening of the rho-meson spectral function consistently describe the observed excess in these measurements. Additionally, we report on measurements of omega-and phi-meson production through their e+ e(-) decay channel. These measurements show good agreement with Tsallis blast-wave model predictions, as well as, in the case of the phi meson, results through its K+ K- decay channel. In the intermediate invariant-mass region (1.1 < Mee < 3 GeV / c(2)), we investigate the spectral shapes from different collision centralities. Physics implications for possible in-medium modification of charmed hadron production and other physics sources are discussed.

Journal ArticleDOI
TL;DR: An efficient and flexible perovskite solar cell based on formamidinium lead trihalide (FAPbI3) with simplified configuration is reported, which suggests its compatibility for scale-up fabrication, which paves the way for commercialization of perovSKite photovoltaic technology.
Abstract: In this communication, we report an efficient and flexible perovskite solar cell based on formamidinium lead trihalide (FAPbI3) with simplified configuration. The device achieved a champion efficiency of 12.70%, utilizing direct contact between metallic indium tin oxide (ITO) electrode and perovskite absorber. The underlying working mechanism is proposed subsequently, via a systematic investigation focusing on the heterojunction within this device. A significant charge storage has been observed in the perovskite, which is believed to generate photovoltage and serves as the driving force for charge transferring from the absorber to ITO electrode as well. More importantly, this simplified device structure on flexible substrates suggests its compatibility for scale-up fabrication, which paves the way for commercialization of perovskite photovoltaic technology.

Journal ArticleDOI
TL;DR: In this paper, aqueous metal complex-based oxide semiconductor films formed with various ligands, such as chloride, acetate, fluoride, and nitrate, were investigated.
Abstract: We investigated aqueous metal complex-based oxide semiconductor films formed with various ligands, such as chloride, acetate, fluoride, and nitrate. Nitrate ligand-based indium(III) precursor was easily decomposed at low temperature due to the replacement of all nitrate ions with water during solvation to form the hexaaqua indium(III) cation ([In(H2O)6]3+). Hexaaqua indium(III) cation was a key complex to realize high-quality oxide films at low temperature. Additionally, Al2O3-based high-k dielectric was also employed by using a nitrate precursor, and the hexaaqua aluminum(III) cation ([Al(H2O)6]3+) was confirmed. This complex-based Al2O3 film showed high breakdown voltage and stable capacitance under high frequency operation compared to organic solvent-based Al2O3 films. We successfully demonstrated aqueous-based In2O3 TFTs with Al2O3 high-k gate dielectrics formed at 250 °C with a wide gate voltage operation and high saturation mobility and on/off ratio of 36.31 ± 2.29 cm2 V–1 s–1 and over 107, respecti...

Journal ArticleDOI
TL;DR: In this article, a large domain monolayer MoS2 triangular flakes were synthesized on Au foils, with the edge length approaching to 80 mm, and the growth process was mediated by two competitive effects with H-2 acting as both a reduction promoter for efficient sulfurization of MoO3 and an etching reagent of resulting MoS 2 flakes.
Abstract: Controllable synthesis of large domain, high-quality monolayer MoS2 is the basic premise both for exploring some fundamental physical issues, and for engineering its applications in nanoelectronics, optoelectronics, etc. Herein, by introducing H-2 as carrier gas, the successful synthesis of large domain monolayer MoS2 triangular flakes on Au foils, with the edge length approaching to 80 mm is reported. The growth process is proposed to be mediated by two competitive effects with H-2 acting as both a reduction promoter for efficient sulfurization of MoO3 and an etching reagent of resulting MoS2 flakes. By using low-energy electron microscopy/diffraction, the crystal orientations and domain boundaries of MoS2 flakes directly on Au foils for the first time are further identified. These on-site and transfer-free characterizations should shed light on the initial growth and the aggregation of MoS2 on arbitrary substrates, further guiding the growth toward large domain flakes or monolayer films.