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Time-resolved Element-selective Probing of Charge Carriers in Solar Materials
摘要： We review our recent results on the implementation of picosecond (ps) X-ray absorption spectroscopy to probe the electronic and geometric structure of centres formed by photoexcitation of solar materials such as polymorphs and inorganic Cs-based perovskites. The results show electron localization at Ti defects in TiO2 anatase and rutile and small hole polaron formation in the valence band of CsPbBr3, all within 80 ps. This method is promising for the study of the ultrafast time scales of such processes, especially with the advent of the Swiss X-ray Free Electron Laser (SwissFEL).
关键词： Solar materials,Ultrafast,Perovskites,X-ray absorption spectroscopy,TiO2
更新于2025-09-23 15:21:01
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Ethanol–water-assisted room temperature synthesis of CsPbBr3/SiO2 nanocomposites with high stability in ethanol
摘要： All-inorganic halide perovskites have attracted great attention by virtue of the merits of bright emission, tunable wavelength and narrow-band emission. Despite the excellent optical features, all-inorganic halide perovskite materials have suffered from intrinsic instability, which has limited their applications in various optoelectronic devices. To mitigate the intractable issue, we demonstrated the CsPbBr3 nanoparticles decorated with smaller SiO2 nanocrystals to passivate the surface defects; SiO2 nanoparticles were applied as a barrier layer to maintain the optical property and enhance environmental stability. A facile in situ method was proposed to prepare CsPbBr3/SiO2 nanocomposites, in which an environmental ethanol/water solvent system was needed with the addition of tetraethyl orthosilicate (TEOS) as a silicon precursor. The obtained CsPbBr3/SiO2 nanocomposites have better optical characteristic and stability than bare CsPbBr3 nanoparticles. Even 70% photoluminescence intensity of as-prepared CsPbBr3/SiO2 nanocomposites can be maintained after 168 h storage in ethanol. This newly developed synthesis will open up a new route for the fabrication of optoelectronic devices in an environmentally friendly way, and the as-obtained perovskite materials with improved stability will make them great potential for multifunctional optoelectronic devices.
关键词： Ethanol–water-assisted room temperature synthesis,All-inorganic halide perovskites,High stability,CsPbBr3/SiO2 nanocomposites,Optoelectronic devices
更新于2025-09-23 15:21:01
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Kinetics of Ion-Exchange Reactions in Hybrid Organic-Inorganic Perovskite Thin Films Studied by In Situ Real-Time X-ray Scattering
摘要： The exchange of ions in hybrid organic-inorganic perovskites with the general formula APbX3 (A = MA, FA; X = I, Cl, Br) is studied in five different systems using in situ real-time grazing incident X-ray diffraction (GIXD). In systems where the organic cation is exchanged, we find a continuous shift of the lattice parameter. The relative shift compared to the pure materials is used to quantify the exchange. Whether or not a conversion is possible, as well as the amount of exchanged cations, depends on the halide used. In the case of the interconversion of MAPbI3 and MAPbCl3, we observe a decay of the diffraction peaks of the original perovskite and the emergence of new peaks corresponding to the structure with the alternative halide. Moreover, we determined the relevant time scales of the growth and decay of the perovskite structures.
关键词： ion-exchange reactions,kinetics,in situ real-time X-ray scattering,thin films,hybrid organic-inorganic perovskites
更新于2025-09-23 15:21:01
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Inorganic Halide Perovskite Solar Cells: Progress and Challenges
摘要： All-inorganic perovskite semiconductors have recently drawn increasing attention owing to their outstanding thermal stability. Although all-inorganic perovskite solar cells (PSCs) have achieved significant progress in recent years, they still fall behind their prototype organic–inorganic counterparts owing to severe energy losses. Therefore, there is considerable interest in further improving the performance of all-inorganic PSCs by synergic optimization of perovskite films and device interfaces. This review article provides an overview of recent progress in inorganic PSCs in terms of lead-based and lead-free composition. The physical properties of all-inorganic perovskite semiconductors as well as the hole/electron transporting materials are discussed to unveil the important role of composition engineering and interface modification. Finally, a discussion of the prospects and challenges for all-inorganic PSCs in the near future is presented.
关键词： perovskites,inorganic perovskite,lead-based,perovskite solar cells,lead-free perovskites
更新于2025-09-23 15:19:57
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Controllable Growth of Higha??Quality Inorganic Perovskite Microplate Arrays for Functional Optoelectronics
摘要： Inorganic perovskite single crystals have emerged as promising vapor-phase processable structures for optoelectronic devices. However, because of material lattice mismatch and uncontrolled nucleation, vapor-phase methods have been restricted to random distribution of single crystals that are difficult to perform for integrated device arrays. Herein, an effective strategy to control the vapor-phase growth of high-quality cesium lead bromide perovskite (CsPbBr3) microplate arrays with uniform morphology as well as controlled location and size is reported. By introducing perovskite seeds on substrates, intractable lattice mismatches and random nucleation barriers are surpassed, and the epitaxial growth of perovskite crystals is accurately controlled. It is further demonstrated that CsPbBr3 microplate arrays can be monolithically integrated on substrates for the fabrication of high-performance lasers and photodetectors. This strategy provides a facile approach to fabricate high-quality CsPbBr3 microplates with controllable size and location, which offers new opportunities for the scalable production of integrated optoelectronic devices.
关键词： perovskites,microdevice arrays,vapor patterning,single crystals
更新于2025-09-23 15:19:57
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Higha??Efficiency CsPbI <sub/>2</sub> Br Perovskite Solar Cells with Dopanta??Free Poly(3a??hexylthiophene) Hole Transporting Layers
摘要： CsPbI2Br is emerging as a promising all-inorganic material for perovskite solar cells (PSCs) due to its more stable lattice structure and moisture resistance compared to CsPbI3, although its device performance is still much behind this counterpart. Herein, a preannealing process is developed and systematically investigated to achieve high-quality CsPbI2Br films by regulating the nucleation and crystallization of perovskite. The preannealing temperature and time are specifically optimized for a dopant-free poly(3-hexylthiophene) (P3HT)-based device to target dopant-induced drastic performance degradation for spiro-OMeTAD-based devices. The resulting P3HT-based device exhibits comparable power conversion efficiency (PCE) to spiro-OMeTAD-based devices but much enhanced ambient stability with over 95% PCE after 1300 h. A diphenylamine derivative is introduced as a buffer layer to improve the energy-level mismatch between CsPbI2Br and P3HT. A record-high PCE of 15.50% for dopant-free P3HT-based CsPbI2Br PSCs is achieved by alleviating the open-circuit voltage loss with the buffer layer. These results demonstrate that the preannealing processing together with a suitable buffer layer are applicable strategies for developing dopant-free P3HT PSCs with high efficiency and stability.
关键词： perovskite solar cells,inorganic perovskites,P3HT
更新于2025-09-23 15:19:57
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Large organic cation incorporation induces vertical orientation growth of Sn-based perovskites for high efficiency solar cells
摘要： The potential toxic issue of lead content is still a problem for prohibiting the commercialization of lead halide perovskite solar cells (PSCs). as an element of group 14 metals, tin (Sn) is the most likely substitute for lead element in perovskites. However, Sn-based PSCs still suffer from the low power conversion efficiency (PCE) because Sn2+ in tin-based perovskites is easily oxidized into Sn4+ once exposed to air. To fabricate stable and efficient Sn-based PSCs, herein we incorporate large ethylammonium (EA+) cation into CH3NH3SnI3 (MASnI3) abided by the Goldschmidt tolerance factor to fabricate vertically oriented 2D/3D mixed perovskite films. The vertically oriented structure provides a direct pathway for electron and hole transport. As a result, the PCE is highly improved to 9.24% and the corresponding PSC still retains 95% of the initial efficiency after being kept for 30 days without encapsulation in the glovebox. Therefore, our results suggest a promising strategy to develop highly efficient and stable Sn-based PSCs.
关键词： high efficiency solar cells,Sn-based perovskites,vertical orientation growth,stability,ethylammonium incorporation
更新于2025-09-23 15:19:57
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Review on recent advances of core-shell structured lead halide perovskites quantum dots
摘要： Lead halide perovskites have shown great potential in photovoltaic and optoelectronic devices due to their high brightness, defect tolerance, tunable emission wavelength, high color purity and near-unity luminescence quantum yield. Conversely, lead halide perovskites (LHP) show poor stability, which received strong criticism despite other promising characteristics. The poor stability attracted much research resulting in various modifications to enhance the stability and photoluminescence quantum yield (PLQY). The review outlines the basic structural and optical properties along with the conventional method of LHP synthesis and its drawbacks. Simultaneously discusses about factors responsible for instability like crystal structure, moisture, solvent, light and temperature. The review exclusively focuses on the recent research on core-shell LHP modification strategy to improve the stability and PLQY and its application in LED devices.
关键词： photoluminescence,Lead halide perovskites,stability,core-shell structure,quantum yield
更新于2025-09-23 15:19:57
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Thina??Film Morphology Improvement and Density Functional Theorya??Driven Findings for the Photovoltaic Perovskite MAPI/MAPSI
摘要： The morphology of thin films of the mixed MAPI / MAPSI material has been studied, revealing that the addition of toluene in the synthesis stage markedly improves the porosity problem of the manufactured films. The presence of crystalline domains of the two materials is verified, as reported by the X-ray diffraction patterns. The calculated band gap values from the diffuse reflectance measurements using the Tauc plots with the Kubelka-Munk transformation function confirm the presence of the two materials in the mixture. On the other hand, the results of the DFT-based computational calculations give answers to the true geometry that the SCN groups adopt within the MAPSI unit cell. The COHP analysis suggests that the most stable structure has an axial geometry for the SCN groups, which is confirmed by the analysis of non-covalent interactions (NCI), in which it is established that there is a greater number of hydrogen bond interactions for the same axial configuration, and results for Electron Localization Functions were shown (ELF), where it is found that there is indeed electron localization (at the level at which a bonding interaction is expected, ELF > 0.8) both for the SCN groups and the methyl-ammonium cations, in the same way as seen in the results of the NCI analyses.
关键词： hybrid perovskites,solar cells,thin films,SEM,DFT calculations
更新于2025-09-23 15:19:57
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Flexible and Selfa??Powered Photodetector Arrays Based on Alla??Inorganic CsPbBr <sub/>3</sub> Quantum Dots
摘要： Flexible devices are garnering substantial interest owing to their potential for wearable and portable applications. Here, flexible and self-powered photodetector arrays based on all-inorganic perovskite quantum dots (QDs) are reported. CsBr/KBr-mediated CsPbBr3 QDs possess improved surface morphology and crystallinity with reduced defect densities, in comparison with the pristine ones. Systematic material characterizations reveal enhanced carrier transport, photoluminescence efficiency, and carrier lifetime of the CsBr/KBr-mediated CsPbBr3 QDs. Flexible photodetector arrays fabricated with an optimum CsBr/KBr treatment demonstrate a high open-circuit voltage of 1.3 V, responsivity of 10.1 A W?1, specific detectivity of 9.35 × 1013 Jones, and on/off ratio up to ≈104. Particularly, such performance is achieved under the self-powered operation mode. Furthermore, outstanding flexibility and electrical stability with negligible degradation after 1600 bending cycles (up to 60°) are demonstrated. More importantly, the flexible detector arrays exhibit uniform photoresponse distribution, which is of much significance for practical imaging systems, and thus promotes the practical deployment of perovskite products.
关键词： self-powered devices,perovskites,flexible devices,photodetector arrays
更新于2025-09-23 15:19:57