Browse
Submit Data
Databases
API
Help

Dataset Information

14 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Great Amplification of Circular Polarization Sensitivity via Heterostructure Engineering of a Chiral Two-Dimensional Hybrid Perovskite Crystal with a Three-Dimensional MAPbI₃ Crystal.

ABSTRACT: Chiral hybrid perovskites have brought an unprecedented opportunity for circularly polarized light (CPL) detection. However, the circular polarization sensitivity of such a detector remains extremely low because of the high exciton recombination rate in those single-phase hybrid perovskites. Here, a heterostructure construction strategy is proposed to reduce the electron-hole recombination rate in a chiral hybrid perovskite and achieve CPL detectors with greatly amplified circular polarization sensitivity. A heterostructure crystal, namely, [(R)-MPA]₂MAPb₂I₇/MAPbI₃ ((R)-MPA = (R)-methylphenethylamine, MA = methylammonium), has been successfully created by integrating a chiral two-dimensional (2D) perovskite with its three-dimensional counterpart via solution-processed heteroepitaxy. Strikingly, the sharp interface of the as-grown heterostructure crystal facilitates the formation of a built-in electric field, enabling the combined concepts of charge transfer and chirality transfer, which effectively reduces the recombination probability for photogenerated carriers while retaining chiroptical activity of chiral 2D perovskite. Thereby, the resultant CPL detector exhibits significantly amplified circular polarization sensitivity at zero bias with an impressive anisotropy factor up to 0.67, which is about six times higher than that of the single-phase [(R)-MPA]₂MAPb₂I₇ (0.1). As a proof-of-concept, the strategy we presented here enables a novel path to modulate circular polarization sensitivity and will be helpful to design chiral hybrid perovskites for advanced chiroptical devices.

SUBMITTER: Zhang X

PROVIDER: S-EPMC8323243 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Circular polarization-resolved ultraviolet photonic artificial synapse based on chiral perovskite.

Project description:Circularly polarized light (CPL) adds a unique dimension to optical information processing and communication. Integrating CPL sensitivity with light learning and memory in a photonic artificial synapse (PAS) device holds significant value for advanced neuromorphic vision systems. However, the development of such systems has been impeded by the scarcity of suitable CPL active optoelectronic materials. In this work, we employ a helical chiral perovskite hybrid combined with single-wall carbon nanotubes to achieve circularly polarized ultraviolet neuromorphic vision sensing and imaging. The heterostructure demonstrates long-term charge storage as evidenced by multiple-pulsed transient absorption measurements and highly sensitive circular polarization-dependent photodetection, thereby enabling efficient CPL-resolved synaptic and neuromorphic behaviors. Significantly, our PAS sensor arrays adeptly visualize, discriminate, and memorize distinct circularly polarized images with up to 93% recognition accuracy in spiking neural network simulations. These findings underscore the pivotal role of chiral perovskites in advancing PAS technology and circular polarization-enhanced ultraviolet neuromorphic vision systems.

| S-EPMC10630371 | biostudies-literature

MAPbI3 microneedle-arrays for perovskite photovoltaic application.

Project description:Methyl-ammonium lead iodide perovskite (MAPbI3) was synthesized in the form of micro-needles via a hydrothermal route at a low temperature of 100 °C in a two-step procedure for the first time. The results exhibit that the amount of the surfactant is crucial for the synthesis of the MAPbI3 nanostructures with well-controlled morphologies. In contrast to bulk MAPbI3, the one-dimensional (1-D) micro-needle perovskite with a diameter of 200 nm showed an improved hole injection from the perovskite to the hole transporting layer (HTL), providing a unique platform at the perovskite/HTL interface. The best performing device employing MAPbI3 perovskite micro-needles yielded stable and hysteresis-free devices with a best power conversion efficiency of (PCEbest) of 17.98%. The current findings highlight the potential of perovskite micro-needles as novel absorber systems and lay the basis for future commercialization.

| S-EPMC9473284 | biostudies-literature

Dual Passivation of Perovskite and SnO2 for High-Efficiency MAPbI3 Perovskite Solar Cells.

Project description:So far, most techniques for modifying perovskite solar cells (PSCs) focus on either the perovskite or electron transport layer (ETL). For the sake of comprehensively improving device performance, a dual-functional method of simultaneously passivating trap defects in both the perovskite and ETL films is proposed that utilizes guidable transfer of Eu3+ in SnO2 to perovskite. Europium ions are distributed throughout the SnO2 film during the formation process of SnO2, and they can diffuse directionally through the SnO2/perovskite interface into the perovskite, while most of the europium ions remain at the interface. Under the synergistic effect of distributed Eu3+ in the SnO2 and aggregated Eu3+ at the interface, the electron mobilities of ETLs are evidently improved. Meanwhile, diffused Eu3+ ions passivate the perovskite to reduce trap densities at the grain boundaries, which can dramatically elevate the open-circuit voltage (V oc) of PSCs. Finally, the mainly PSCs coated on SnO2:Eu3+ ETL achieve a power conversion efficiency of 20.14%. Moreover, an unsealed device degrades by only 13% after exposure to ambient atmosphere for 84 days.

| S-EPMC7927604 | biostudies-literature

All-Inorganic Perovskite Quantum Dot-Monolayer MoS2 Mixed-Dimensional van der Waals Heterostructure for Ultrasensitive Photodetector.

Project description:2D transition metal dichalcogenide (2D-TMD) materials and their van der Waals heterostructures (vdWHs) have inspired worldwide efforts in the fields of electronics and optoelectronics. However, photodetectors based on 2D/2D vdWHs suffer from performance limitations due to the weak optical absorption of their atomically thin nature. In this work, taking advantage of an excellent light absorption coefficient, low-temperature solution-processability, and long charge carrier diffusion length, all-inorganic halides perovskite CsPbI3- x Br x quantum dots are integrated with monolayer MoS2 for high-performance and low-cost photodetectors. A favorable energy band alignment facilitating interfacial photocarrier separation and efficient carrier injection into the MoS2 layer inside the 0D-2D mixed-dimensional vdWHs are confirmed by a series of optical characterizations. Owing to the synergistic effect of the photogating mechanism and the modulation of Schottky barriers, the corresponding phototransistor exhibits a high photoresponsivity of 7.7 × 104 A W-1, a specific detectivity of ≈5.6 × 1011 Jones, and an external quantum efficiency exceeding 107%. The demonstration of such 0D-2D mixed-dimensional heterostructures proposed here would open up a wide realm of opportunities for designing low-cost, flexible transparent, and high-performance optoelectronics.

| S-EPMC6299711 | biostudies-literature

CsPbBr3-CdS heterostructure: stabilizing perovskite nanocrystals for photocatalysis.

Project description:The instability of cesium lead bromide (CsPbBr3) nanocrystals (NCs) in polar solvents has hampered their use in photocatalysis. We have now succeeded in synthesizing CsPbBr3-CdS heterostructures with improved stability and photocatalytic performance. While the CdS deposition provides solvent stability, the parent CsPbBr3 in the heterostructure harvests photons to generate charge carriers. This heterostructure exhibits longer emission lifetime (τ ave = 47 ns) than pristine CsPbBr3 (τ ave = 7 ns), indicating passivation of surface defects. We employed ethyl viologen (EV2+) as a probe molecule to elucidate excited state interactions and interfacial electron transfer of CsPbBr3-CdS NCs in toluene/ethanol mixed solvent. The electron transfer rate constant as obtained from transient absorption spectroscopy was 9.5 × 1010 s-1 and the quantum efficiency of ethyl viologen reduction (Φ EV+˙) was found to be 8.4% under visible light excitation. The Fermi level equilibration between CsPbBr3-CdS and EV2+/EV+˙ redox couple has allowed us to estimate the apparent conduction band energy of the heterostructure as -0.365 V vs. NHE. The insights into effective utilization of perovskite nanocrystals built around a quasi-type II heterostructures pave the way towards effective utilization in photocatalytic reduction and oxidation processes.

| S-EPMC8597851 | biostudies-literature

Fast and Accurate Artificial Neural Network Potential Model for MAPbI3 Perovskite Materials.

Project description:Hybrid organic-inorganic perovskite materials are promising materials for photovoltaic and optoelectronic applications. Nevertheless, the construction of a computationally efficient potential model for atomistic simulations of perovskite with high fidelity to ab initio calculations is not a trivial task given the chemically complex nature of perovskite in terms of its chemical components and interatomic interactions. In the present study, we demonstrate that artificial neural network (ANN) models can be employed for efficient and accurate potential energy evaluation of MAPbI3 perovskite materials. The ANN models were trained using training sets composed of thousands of atomic images of tetragonal MAPbI3 crystals, with their respective energies and atomic forces obtained from ab initio calculations. The trained ANN models were validated by predicting the lattice parameters and energies/atomic forces of cubic MAPbI3 perovskite and had excellent agreement with ab initio calculations. The phonon modes could also be extracted using the trained ANN model with good agreement with ab initio calculations, provided that the atomic forces were incorporated into the training processes. Finally, we demonstrate that for a given system size, the trained ANN model offers 104 to 105 faster time consumption per energy evaluation relative to ab initio calculations using Vienna Ab initio Simulation Package, demonstrating the potential of the ANN model for exhaustively sampling the configuration spaces of chemically complex materials for predictions of thermodynamic properties and phase stabilities.

| S-EPMC6648651 | biostudies-literature

Accelerated Hot-Carrier Cooling in MAPbI3 Perovskite by Pressure-Induced Lattice Compression.

Project description:Hot-carrier cooling (HCC) in metal halide perovskites above the Mott transition is significantly slower than in conventional semiconductors. This effect is commonly attributed to a hot-phonon bottleneck, but the influence of the lattice properties on the HCC behavior is poorly understood. Using pressure-dependent transient absorption spectroscopy, we find that at an excitation density below the Mott transition, pressure does not affect the HCC. On the contrary, above the Mott transition, HCC in methylammonium lead iodide is around 2-3 times faster at 0.3 GPa than at ambient pressure. Our electron-phonon coupling calculations reveal ∼2-fold stronger electron-phonon coupling for the inorganic cage mode at 0.3 GPa. However, our experiments reveal that pressure promotes faster HCC only above the Mott transition. Altogether, these findings suggest a change in the nature of excited carriers above the Mott transition threshold, providing insights into the electronic behavior of devices operating at such high charge-carrier densities.

| S-EPMC8154846 | biostudies-literature

Enhanced Stability of MAPbI3 Perovskite Solar Cells using Poly(p-chloro-xylylene) Encapsulation.

Project description:We demonstrated an effective poly(p-chloro-xylylene) (Parylene-C) encapsulation method for MAPbI3 solar cells. By structural and optical analysis, we confirmed that Parylene-C efficiently slowed the decomposition reaction in MAPbI3. From a water permeability test with different encapsulating materials, we found that Parylene-C-coated MAPbI3 perovskite was successfully passivated from reaction with water, owing to the hydrophobic behavior of Parylene-C. As a result, the Parylene-C-coated MAPbI3 solar cells showed better device stability than uncoated cells, virtually maintaining the initial power conversion efficiency value (15.5?±?0.3%) for 196?h.

| S-EPMC6820723 | biostudies-literature

Luminescent Intermediates and Humidity-Dependent Room-Temperature Conversion of the MAPbI3 Perovskite Precursor.

Project description:Preparation of metal-halide perovskites under room temperature attracts attention because of energy saving by removing thermal annealing. Room-temperature transformation of spin-cast wet films consisting of methylammonium (MA) iodide, PbI2, and dimethylformamide toward solid MAPbI3 perovskite proceeds via several intermediate crystalline states and is strongly dependent on ambient humidity. Light transmission and photoluminescence (PL) microscopy and spectroscopy were used to monitor the growth of crystals and transformation of their properties in time under nitrogen atmosphere at room temperature. Under low humidity, a highly luminescent intermediate phase with low absorption in the visible range appears, with the PL spectra composed of several bands in the range from 600 to 760 nm. We assign these bands to low-dimensional (nanocrystals and two-dimensional inclusions) MAPbI3 intermediates, where the exciton confinement shifts the spectrum to higher energies in comparison with the bulk MAPbI3. The intermediate levels of ambient humidity (10-50%) appear to catalyze the conversion of the intermediate phase to MAPbI3. At a high ambient humidity (>80%), the initially formed MAPbI3 is quickly transformed to the transparent hydrate phase of MAPbI3. The role of ambient water catalyzing the material transformation by competing for Pb coordination with the solvent molecules is discussed.

| S-EPMC6644872 | biostudies-literature

Auger Electron Spectroscopy Analysis of the Thermally Induced Degradation of MAPbI3 Perovskite Films.

Project description:Organometal halide perovskites are highly promising materials for photovoltaic applications due to the rapid growth of power conversion efficiency in recent years. However, thermal stability is still a major hurdle for perovskite solar cells toward commercialization. Herein, we first explore the slow thermal response of the CH3NH3PbI3 perovskite crystal investigated via Auger electron spectroscopy (AES). AES image mapping directly observes the evolution of morphology and elemental distribution over time. The AES small spot analysis demonstrates the precise initial degradation position of perovskite with both information regarding physical changes in crystals and chemical changes in elemental bonding at the nanometer scale. X-ray photoelectron spectroscopy (XPS) was used to confirm the surface chemical bonding and composition of the perovskite crystals. This work provides the first insights into the physical and chemical changes of perovskites investigated by AES upon long-term exposure to heat under ambient conditions.

| S-EPMC8697411 | biostudies-literature