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Non-radiative processes in metal halide perovskite semiconductors probed by photoluminescence microscopy
摘要： Organo metal halide perovskites are solution processed semiconductors that recently attracted a great attention. They possess a rather “soft” and (photo) chemically active solid structure allowing for ion migration and other mass diffusion processes. This is a likely reason why non-radiative recombination centres in these materials are activated and de-activated on relatively slow time-scales. This dynamics reveals as photoluminescence (PL) fluctuations (blinking) of individual microcrystals and local areas of films and allows for application of a broad range of single molecule spectroscopy methods including optical super-resolution. Studying PL blinking resolves properties of individual non-radiative centres and helps to unravel their chemical nature.
关键词： perovskite,metal halide,Non-radiative processes,semiconductors,photoluminescence microscopy
更新于2025-09-23 15:21:21
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Using Data Mining to Search for Perovskite Materials with Higher Specific Surface Area
摘要： The specific surface area (SSA) of ABO3-type perovskite is one of important properties associating with photocatalytic ability. In this work, data mining methods were used to explore the relationship between the SSA (ranged 1-60m2g-1) of perovskite with its features including chemical compositions and technical parameters. The genetic algorithm (GA)-support vector regression (SVR) method was used to screen the main features for modeling. The correlation coefficient (R) between predicted SSA and experimental SSA reached as high as 0.986 for training set and 0.935 for leave-one-out cross validation (LOOCV), respectively. The ABO3-type perovskite with higher SSA can be screened out by using OCPMDM (online computation platform for materials data mining) developed in our laboratory. Further, an online web server has been developed to share the model for the prediction of SSA of ABO3-type perovskite，which is accessible at the web address：http://118.25.4.79/material_api/csk856q0fulhhhwv
关键词： Visual screening,Online service,Data mining,Specific surface area,Perovskite
更新于2025-09-23 15:21:21
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Increased luminescent efficiency of perovskite light emitting diodes based on modified two-step deposition method providing gradient concentration
摘要： We increased the luminescent efficiency of perovskite light-emitting diodes (PeLEDs) by using a modified two-step deposition method combined with an interdiffusion process without additional solvent engineering or additive molecules. Methylammonium lead bromide (MAPbBr3) polycrystalline films with nanosized grains and low electronic disorder were fabricated by a modified two-step deposition process. The as-fabricated MAPbBr3 films showed gradient concentration characteristics as a result of a gradient distribution of the MABr. Also, the MABr-gradient concentration structure was intensified by the interdiffusion process, showing improved performance of MAPbBr3 PeLEDs with maximum current efficiency CEmax = 0.861 cd A?1 and maximum luminance = 604 cd m?2 with very narrow electroluminescence spectral width. This is the highest CEmax among MAPbBr3-based PeLEDs deposited by the two-step deposition method.
关键词： two-step deposition method,perovskite light-emitting diodes,luminescent efficiency,gradient concentration,interdiffusion process
更新于2025-09-23 15:21:21
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Achieving Near-Unity Photoluminescence Efficiency for Blue-violet Emitting Perovskite Nanocrystals
摘要： While the perovskite nanocrystals (NCs) have shown great promise as materials for efficient light emitting diodes (LEDs), low photoluminescence quantum yield (PLQY) of the blue-emitting perovskites is an impediment to the development of white LEDs of which blue is an essential component. Herein, we report that room temperature post-synthetic treatment of weakly blue-violet emitting (PLQY 3%) CsPbCl3 NCs with CdCl2 results in an instantaneous enhancement of the PLQY to near-unity without affecting the PL peak position (406 nm) and spectral width. The time-resolved PL and ultrafast transient absorption measurements confirm the removal of nonradiative defect states of the CsPbCl3 NCs in treated sample. The elemental composition and structural data of the treated sample reveal facile doping of Cd2+ into the crystal lattice without affecting the size and shape of the NCs. Extraordinary PLQY, high air- and photo-stability and ease of preparation of this Cd-doped CsPbCl3 make it by far the most attractive blue-emitting perovskite for development of efficient blue and white LEDs.
关键词： photoluminescence quantum yield,blue-emitting perovskites,perovskite nanocrystals,CdCl2 treatment,white LEDs
更新于2025-09-23 15:21:21
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Research progress of low-dimensional metal halide perovskites for lasing applications
摘要： Metal halide perovskites have been regarded as remarkable materials for next-generation light-harvesting and light emission devices. Due to their unique optical properties, such as high absorption coefficient, high optical gain, low trapping-state density, and ease of band gap engineering, perovskites promise to be used in lasing devices. In this article, the recent progresses of microlasers based on reduced-dimensional structures including nanoplatelets, nanowires, and quantum dots are reviewed from both fundamental photophysics and device applications. Furthermore, perovskite-based plasmonic nanolasers and polariton lasers are summarized. Perspectives on perovskite-based small lasers are also discussed. This review can serve as an overview and evaluation of state-of-the-art micro/nanolaser science.
关键词： microlaser,laser,nanostructure,emission,perovskite
更新于2025-09-23 15:21:21
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Giant exchange bias in the single-layered Ruddlesden-Popper perovskite
摘要： Exchange bias (EB) as large as ～5.5 kOe is observed in SrLaCo0.5Mn0.5O4, which is the highest ever found in any layered transition-metal oxides including Ruddlesden-Popper series. Neutron-diffraction measurement rules out long-range magnetic ordering and together with dc magnetic measurements suggests formation of short-range magnetic domains. Ac magnetic susceptibility, magnetic memory effect, and magnetic training effect con?rm the system to be a cluster spin glass. By carrying out density functional calculations on several model con?gurations, we propose that EB is originated at the boundary between Mn-rich antiferromagnetic and Co-rich ferromagnetic domains at the subnanoscale. Reversal of magnetization axis on the Co side alters the magnetic coupling between the interfacial Mn and Co spins, which leads to EB. Our analysis infers that the presence of competing magnetic interactions is suf?cient to induce exchange bias and thereby a wide range of materials exhibiting giant EB can be engineered for designing novel magnetic memory devices.
关键词： Ruddlesden-Popper perovskite,Exchange bias,cluster spin glass,magnetic memory devices
更新于2025-09-23 15:21:21
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Comprehensive Understanding and Controlling the Defect Structures: An Effective Approach for Organic-Inorganic Hybrid Perovskite-Based Solar-Cell Application
摘要： Understanding the defect structure in organic-inorganic hybrid perovskite material (OHP) is a crucial role to explain several physical properties such as material stability, energy band, carrier mobility, and so on. In the solar-cell applications using OHP, finding, understanding, and controlling defects is essential to making a more advanced device with high efficiency and stability. Naturally, we need to find, understand, and control the possible defects in OHP. However, the defect research field in OHP material is just beginning now. In this short review, we will explore the kinds of defects and their effects on OHP.
关键词： molecular defect,organic-inorganic hybrid perovskite,Schottky/Frankel defect,vacancy,delocalized defect,thin film,defect,solar-cell
更新于2025-09-23 15:21:21
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Ether-soluble Cu53 Nanoclusters as an Effective Precursor of High-quality CuI Films for Optoelectronic Applications
摘要： An effective strategy is developed to synthesize high-nuclearity Cu clusters, [Cu53(RCOO)10(C≡CtBu)20Cl2H18]+ (Cu53), which is the largest Cu(I)/Cu(0) cluster reported to date. Cu powder and Ph2SiH2 are employed as the reducing agents in the synthesis. As revealed by single-crystal diffraction, Cu53 is arranged as a four-concentric-shell Cu3@Cu10Cl2@Cu20@Cu20 structure, possessing an atomic arrangement of concentric M12 icosahedral and M20 dodecahedral shells which popularly occurs in Au/Ag nanoclusters. Surprisingly, Cu53 can be dissolved in diethyl ether and spin coated to form uniform nanoclusters film on organo-lead halide perovskite. The cluster film can subsequently be converted into high-quality CuI film via in-situ iodination at room temperature. The as-fabricated CuI film proves to be an excellent hole-transport layer for fabricating highly stable CuI-based perovskite solar cells (PSCs) with 14.3% of efficiency.
关键词： CuI film,Cu nanocluster,Alkynyl,Perovskite solar cells,Superatoms
更新于2025-09-23 15:21:21
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Outdoor performance of perovskite solar technology: Silicon comparison and competitive advantages at different irradiances
摘要： Perovskite solar cells have shown an impressive performance evolution during the last years. This technology has been mostly tested under laboratory conditions using small area devices. In this work, the outdoor photovoltaic performance of perovskite solar cells was evaluated under real tropical weather conditions. Specifically, two perovskite modules with active area of 17 and 50 cm2 were fabricated, encapsulated and tested. Taking a commercial silicon panel as reference, both technologies were evaluated for 500 h correlating the in-situ I-V measurements with atmospheric variables measured every minute during the light hours. To obtain the performance and the average outdoor efficiency of devices, we proposed a new adapted methodology based on the standard IEC 61853-1, showing the photovoltaic parameters performance through maps, to graphically visualize their behavior in a broad range of atmospheric conditions. Additionally, we demonstrated that the power delivery and short circuit current of both technologies correlate linearly with the atmospheric variables. Moreover, the open circuit voltage of perovskite technology exhibited a nonlinear behavior and an improved performance with temperature at high irradiance regimes. This work presents reliable information concerning perovskite solar technology performance under real outdoor operation conditions, being this crucial to identify competitive advantages of this technology and the aspects to be improved.
关键词： Temperature,power delivery,Outdoor performance,Irradiance,Perovskite solar cells,Minimodules
更新于2025-09-23 15:21:21
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Integral Method Analysis of Electroabsorption Spectra and Electrophotoluminescence Study of (C <sub/>4</sub> H <sub/>9</sub> NH <sub/>3</sub> ) <sub/>2</sub> Pbl <sub/>4</sub> Organic–Inorganic Quantum Well
摘要： Electric-field-induced changes in absorption and photoluminescence (PL) spectra and in PL decay profile have been measured for two-dimensional hybrid organic?inorganic halide perovskite semiconductor, ((C4H9NH3)2Pbl4) (N1). Electro-absorption (E-A) spectra observed at room temperature and at a low temperature of 45 K were analyzed by assuming the Stark shift, and the magnitudes of the change in electric dipole moment and polarizability following photoexcitation were determined. The strong signal observed in the E-A spectra at 45 K was interpreted in terms of the weak absorption band which shows extremely large Stark shift resulting from the large change in polarizability following photoexcitation. Electrophotoluminescence spectra of this compound, that is, field-induced change in PL spectra, show that PL of N1 is quenched by the application of electric field. Field effects on PL decay profiles show that the quenching results both from the field-induced decrease of the population of the emitting state following photoexcitation and from the field-induced lifetime shortening caused by the enhancement of the nonradiative decay rate at the emitting state. At a low temperature of 45 K, two exciton emissions, each of which originates from different phase, appear, and both emissions are quenched by the applied electric field with different efficiencies from each other. It is also found that trap emissions observed at low temperature in the wavelength region longer than the sharp exciton bands show more efficient field-induced quenching than that of the exciton emissions, suggesting that energy transfer from the photoexcited state to trapped states is decelerated by the applied electric field.
关键词： Electrophotoluminescence,Electroabsorption,Perovskite,Stark Shift,Quantum Well
更新于2025-09-23 15:21:21