Search Results (2,997)

Bismuth-based perovskite derivatives, (CH₃NH₃)₃Bi₂I₉ (MBI), are promising non-toxic light-absorbing materials widely used in various photoelectric devices because of their excellent stability. However, MBI-based perovskite solar cells (PSCs) are limited by poor film quality, and the performance of such a device is far behind that of lead-based PSCs. In this work, the crystal structure and morphological properties of MBI films were compared across different preparation methods. The two-step vapor-assisted method can prepare continuous dense MBI films because MBI crystal nucleation is induced by the BiI₃ seed layer. The MBI film grown by this method is better for the production of excellent PSCs compared to the film prepared by the solution method. The best photovoltaic device based on the MBI film could obtain a power conversion efficiency of 1.13%. An MBI device is stored in the glove box for 60 days, and the device’s performance is maintained at 99%. These results indicate that the vapor-assisted deposition of MBI films can be an effective method to improve the performance of bismuth-based planar PSCs. Full article

Organic–inorganic lead halide perovskite solar cells (PSCs) have presented promising improvements within recent years due to the superior photophysical properties of perovskites. The efficiency of PSCs is closely related to the quality of the of the perovskite film. Additive engineering is an effective strategy to regulate the crystallization of perovskite film. Therefore, in this work, we introduce methylammounium chloride (MACl) into a perovskite precursor as an additive to improve the crystallization of perovskite film and to suppress the formation of defects to achieve high-performance PSCs. By meticulously investigating and studying the influence of different percentages of MACl additives on perovskite film quality, we obtain that the best amount of incorporated MACl is 10%. Thanks the employment of the optimal amount of MACl, the perovskite film shows a significantly improved morphology with larger grains, a smoother surface, and suppressed defects. Finally, the target PSCs with the addition of 10% MACl present the highest PCE of 23.61%, which is much higher than the value (16.72%) of the control device. Full article

The perovskite solar cell (PSC) is undergoing intense study to meet sustainable energy and environmental demands. However, large-sized solar cells will degrade the power conversion efficiency, thus concentrating light on small-size devices would be a solution. Here, we report the performance of a p–i–n structured device using CH₃NH₃PbI₃ (MAPbI₃) as the active layer with an area of 6 mm². We prove that the power output would be up to 4.2 mW under 10 Suns compared to the 0.9 mW obtained under 1 Sun; however, this results in an actual efficiency drop of the PSC. Further, using a SCAPS device simulation, we found that the intrinsic properties, such as mobility and defect density, of MAPbI₃ has no profound influence on the relationship between light intensity and power conversion efficiency (PCE), but the series resistance is the dominant limiting factor on the performance of the PSC under high illumination intensities. Our work suggests the potential of perovskite in concentrating photovoltaics and makes recommendations for future development. Full article

Developing more effective gold–support synergy is essential for enhancing the catalytic performance of supported gold nanoparticles (AuNPs) in the gas-phase oxidation of ethanol to acetaldehyde (AC) at lower temperatures. This study demonstrates a significantly improved Au–support synergy achieved by copper doping in LaMO₃ (M = Mn, Fe, Co, Ni) perovskites. Among the various Au/LaMCuO₃ catalysts, Au/LaMnCuO₃ exhibited exceptional catalytic activity, achieving an AC yield of up to 91% and the highest space-time yield of 764 g_AC g_Au⁻¹ h⁻¹ at 225 °C. Notably, this catalyst showed excellent hydrothermal stability, maintaining performance for at least 100 h without significant deactivation when fed with 50% aqueous ethanol. Comprehensive characterization reveals that Cu doping facilitates the formation of surface oxygen vacancies on the Au/LaMCuO₃ catalysts and enhances Au–support interactions. The LaMnCuO₃ perovskite stabilizes the crucial Cu⁺ species, resulting in a stable Au-Mn-Cu synergy within the Au/LaMnCuO₃ catalyst, which facilitates the activation of O₂ and ethanol at lower temperatures. The optimization of the reaction conditions further improves AC productivity. Kinetic studies indicate that the cleavages of both the O-H bond and the α-C-H bond of ethanol are the rate-controlling steps. Full article

This article aims to complete a review of current literature describing the measurement and characterization of photoelectric and geometric properties of perovskite solar cell (PSC) film layer materials using the spectroscopic ellipsometry (SE) measurement technique. Firstly, the influence of film quality on the performance of PSCs is combed and analyzed. Secondly, SE measurement technology is systematically introduced, including the measurement principle and data analysis. Thirdly, a detailed summary is provided regarding the characterization of the geometric and optoelectronic properties of the substrate, electron transport layer (ETL), perovskite layer, hole transport layer (HTL), and metal electrode layer using SE. The oscillator models commonly used in fitting film layer materials in PSCs are comprehensively summarized. Fourthly, the application of SE combined with various measurement techniques to assess the properties of film layer materials in PSCs is presented. Finally, the noteworthy direction of SE measurement technology in the development of PSCs is discussed. The review serves as a valuable reference for further enhancing the application of SE in PSCs, ultimately contributing to the commercialization of PSCs. Full article

The use of organic halide salts to passivate metal halide perovskite (MHP) surface defects has been studied extensively. Passivating the surface defects of the MHP is of critical importance for realizing highly efficient and stable perovskite solar cells (PSCs). Here, the successful application of a multifunctional organic salt, methyltriphenylphosphonium iodide (MTPPI), used as a passivation additive for grain boundary defects and as a molecular sealing layer in terms of stabilization, has been used to stabilize the mixed cation perovskite RbCsMAFA-PbIBr. To assess the passivating and stabilizing effects of MTPPI on RbCsMAFA-PbIBr PSCs, maximum power point tracking (MPPT) was applied as the most realistic and closest-to-application condition for the ageing test. Here, perovskite solar cells were aged under a light source yielding an excitation intensity corresponding to one sun with maximum power point tracking, which was interrupted periodically by current–voltage sweeps. This allowed for the extraction of all photovoltaic parameters necessary for a proper understanding of the ageing process. The MTPPI additive can donate iodine anions to halide vacancies and compensate a negative surface excess charge with cation interactions. On top of this, the large and bulky methyltriphenylphosphonium (MTPP⁺) cation may block both the escape of volatile perovskite components and the ingress of oxygen and water vapour. These collective roles of MTPPI have improved both the efficiency and stability of the solar cells compared to the reference without passivation additives. Full article

Halide perovskite nanocrystals have rapidly emerged as a prominent research topic in materials science over the past decade owing to their exceptional optoelectronic properties and tunability. Their distinctive characteristics, including high light absorption coefficients, high quantum yields, narrow-band emissions, low defect densities, and adjustable chemical compositions and sizes, position them as highly promising candidates for applications in optoelectronic devices, energy conversion units, and other related systems. However, due to the toxicity and instability of halide perovskite nanocrystals, their widespread application in the biomedical field has been limited in the past. In recent years, numerous innovative coating strategies have been reported to effectively enhance the stability of halide perovskite nanocrystals while confining their toxic metal ions within the coating layers, thereby significantly improving their biocompatibility. This review provides a comprehensive summary of the recent progress of halide perovskite nanocrystals in the field of biomedicine. It covers coating strategies to enhance stability and biocompatibility, as well as the applications of coated halide perovskite nanocrystals in biomedicine, with a particular focus on their unique advantages in bioimaging and chemical sensing. Finally, we address unresolved issues and challenges, such as the metabolic pathways and final products of halide perovskite nanocrystals in vivo. We hope to inspire researchers in the field and provide direction for future studies. Full article

Metallic Pd/Ni gauzes, located downstream of the Pt/Rh ammonia oxidation catalyst nets in the Ostwald process, is the current technology for capturing volatile gas phase platinum and rhodium species lost from the Pt/Rh combustion catalyst through evaporation. In this screening study, we explore four oxide families, ABO₃ perovskites, (ABO₃)_n(AO) Ruddlesden–Popper (RP) phases, AO rock salt, and A₂O₃ sesquioxide type oxides, as alternative materials for platinum capture. It was found that all the tested nickelates, LaNiO₃, NdNiO₃, La₂NiO₄, and La₄Ni₃O₁₀, captured platinum well and formed A₂NiPtO₆. In contrast, La_0.85Sr_0.15FeO₃, LaFeO₃, and LaCoO₃ did not capture platinum. CaO, SrO, and Nd₂O₃ formed low-dimensional platinates such as Ca_xPt₃O₄, Sr₄PtO₆, and a newly discovered neodymium platinate, Nd_10.67Pt₄O₂₄. Gd₂O₃ did not capture platinum in bench-scale experiments in dry air, but did, however, seem to capture platinum under pilot plant conditions, likely due to the co-capture of Co lost from the N₂O abatement catalyst. The catalytic activity of both oxides and platinum-containing products were studied, toward NO_x and N₂O decomposition. None of the oxides showed significant activity toward NO_x decomposition, and all showed activity toward N₂O decomposition, but to different extents. An overall assessment of the screened oxides with respect to potential use in industrial Ostwald conditions is provided. All tested oxides except CaO and SrO withstood industrial conditions. From our assessments, the nickelates and A₂O₃ (A = Nd, Gd) stand out as superior oxides for platinum capture. Full article

At present, lead halide PVSKSCs are promising photovoltaic cells but have some limitations, including their low stability in ambient conditions and the toxicity of lead. Thus, it will be of great significance to explore lead-free perovskite materials as an alternative absorber layer. In recent years, the numerical simulation of perovskite solar cells (PVSKSCs) via the solar cell capacitance simulation (SCAPS) method has attracted the attention of the scientific community. In this work, we adopted SCAPS for the theoretical study of lead (Pb)-free PVSKSCs. A cesium bismuth iodide (CsBi₃I₁₀; CBI) perovskite-like material was used as an absorber layer. The thickness of the CBI layer was optimized. In addition, different electron transport layers (ETLs), such as titanium dioxide (TiO₂), tin oxide (SnO₂), zinc oxide (ZnO), and zinc selenide (ZnSe), and different hole transport layers, such as spiro-OMeTAD (2,2,7,7-tetrakis(N,N-di(4-methoxyphenylamine)-9,9′-spirobifluorene), poly(3-hexylthiophene-2,5-diyl) (P₃HT), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA), and copper oxide (Cu₂O), were explored for the simulation of CBI-based PVSKSCs. A device structure of FTO/ETL/CBI/HTL/Au was adopted for simulation studies. The simulation studies showed the improved photovoltaic performance of CBI-based PVSKSCs using spiro-OMeTAD and TiO₂ as the HTL and ETL, respectively. An acceptable PCE of 11.98% with a photocurrent density (J_sc) of 17.360258 mA/cm², a fill factor (FF) of 67.10%, and an open-circuit voltage (V_oc) of 1.0282 V were achieved under the optimized conditions. It is expected that the present study will be beneficial for researchers working towards the development of CBI-based PVSKSCs. Full article

This review provides an analysis of non-perovskite hybrid halides of coinage metals templated by metal–organic cations (CCDC November 2023). These materials display remarkable structural diversity, from zero-dimensional molecular complexes to intricate three-dimensional frameworks, allowing fine-tuning of their properties. A total of 208 crystal structures, comprising haloargentates, mixed-metal haloargentates, and halocuprates, are categorized and examined. Their potential in photocatalysis is discussed. Special attention is given to the structural adaptability of these materials for the generation of functional interfaces. This review highlights key compounds and aims to inspire further research into optimizing hybrid halides for advanced technological applications. Full article

In the present work, nine ‘defect’ perovskites with the chemical formula A₂ZrX₆ have been studied, where the A-site cations are a methylammonium cation, formamidinium cation, and trimethyl-sulfonium cation and the X-site anions are halogen, X = Cl, Br, and I. We employ periodic DFT calculations using GGA-PBE, MBJ, HSEsol, and HSE06 functionals. All studied compounds exhibit a wide-bandgap energy that ranges from 5.22 eV to 2.11 eV, while for some cases, geometry optimization led to significant structural modification. It was found that the increase in the halogen size resulted in a decrease in the bandgap energy. The choice of the organic A-site cation affects the bandgap as well, which is minimal for the methylammonium cation. Such semiconductors with organic cations may be utilized in optoelectronic devices, given the substantial benefit of solution processability and thin film formation compared to purely inorganic analogs, such as Cs₂ZrX₆. Full article

In this paper, the synthesis, characterization, and investigation of electrocatalytic properties of perovskites of general formula PrMn_0.5M_0.5O₃ (M = Cr, Fe, Co, Ni) are presented. The synthesis was conducted by the solution combustion method using glycine as a fuel. The perovskite with the formula PrMn_0.5Fe_0.5O₃ was also synthesized by the sol–gel combustion method with citric acid as fuel. The obtained perovskites were investigated by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), infrared spectroscopy, and cyclic voltammetry. The XRPD patterns showed that the compounds are pure and isostructural within the series. The unit cell parameters of the compounds were determined within the Pnma space group, and several crystallochemical parameters were calculated and discussed. The recorded SEM images of the perovskites revealed a porous morphology, while the EDX analysis confirmed the 2:1:1 atomic percentage ratio of Pr:Mn:M. Within this investigation, the electrocatalytic properties of the obtained perovskites towards oxidation of OH⁻ ions and H₂O₂ oxidation in phosphate buffer were studied by cyclic voltammetry, using a paraffin-impregnated graphite electrode (PIGE) modified with microcrystals of the investigated perovskites. PrMn_0.5Fe_0.5O₃ showed high electrocatalytic activity for OH⁻ oxidation, while both PrMn_0.5Fe_0.5O₃ and PrMn_0.5Co_0.5O₃ exhibited significant efficiency for H₂O₂ oxidation, with a distinct oxidation peak with a peak potential of 0.6 V. Full article

Two-dimensional tin halide perovskites are of significant interest for light emitting applications. Here, we investigate the effect of organic cation A on the stability of different Dion–Jacobson tin-based halide perovskites. The ASnBr₄ materials using diammonium cation A with shorter alkyl chains are found to exhibit improved stability, exhibiting dramatic stability difference between the most stable HDASnBr₄, where HDA denotes 1,6-hexanediammonium, and two materials with 8- and 10-carbon alkyl chain ammonium cations. The HDASnBr₄ powders were thermally stable at 100 °C in an argon environment but exhibited decreasing photoluminescence with time in ambient air at 100 °C. The sample degradation at 100 °C is accelerated compared to room temperature, but it proceeds along similar pathways, namely phase transformation followed by perovskite decomposition. Light emission from HDASnBr₄ thin films could be further enhanced by methanol vapor treatment, and warm white emission with Commission Internationale de l’Eclairage (CIE) coordinates (0.37, 0.34) could be obtained by combining HDASnBr₄ with a blue-emitting polymer film, while direct mixing of blue phosphor and HDASnBr₄ powder yields white emission with CIE coordinates of (0.34, 0.32). Full article

Water molecules from the environment or human breath are one of the main factors affecting the accuracy, efficiency, and long-term stability of electronic gas sensors. In this contribution, yttrium (Y)-doped La₂Ti₂O₇ (LTO) nanosheets were synthesized by a hydrothermal reaction, demonstrating improved proton conductivity compared to their non-doped counterparts. The response of Y-doped LTO with the optimal doping concentration to 100 ppm NO₂ at 43% relative humidity (RH) was −21%, which is four times higher than that of bare La₂Ti₂O₇. As the humidity level increased to 75%, the response of Y-doped LTO further increased to −64%. Unlike the gas doping effect observed in previous studies of semiconducting metal oxides, the sensing mechanism of Y-doped LTO nanosheets is based on the enhanced dissociation of H₂O in the presence of target NO₂ molecules, leading to the generation of more protons for ion conduction. This also resulted in a greater resistance drop and thus a larger sensing response at elevated humidity levels. Our work demonstrates that proton-conductive oxide materials are promising gas-sensing materials under humid conditions. Full article

In recent years, there has been significant investigation into the high efficiency of perovskite solar cells. These cells have the capacity to attain efficiencies above 14%. As the perovskite materials that include lead pose a substantial environmental risk, components that are free from lead are used during the process of solar cell development. In this work, we use a lead-free double-perovskite material, namely Cs₂TiBr₆, as the main absorbing layer in perovskite solar cells to enhance power conversion efficiency (PCE). This work is centered on the development of solar cell structures with materials such as an ETL (electron transport layer) and an HTL (hole transport layer) to enhance the PCE. In this theoretical work, we perform simulations and analysis on double-perovskite Cs₂TiBr₆ to assess its efficacy as an absorber material in various HTLs like Cu₂O and CuI, with a fixed ETL of C60 using SCAPS (Solar Cell Capacitance Simulator, SCAPS 3.3.10) Software. This is a one-dimensional solar cell simulation program. In this work, the thickness of the double-perovskite material is also varied between 0.2 and 2.0 µm, and its efficiency is observed. The effect of temperature variation on efficiency in the range of 300 K to 350 K is observed. The effect of defect density on efficiency is also observed in the range of 1 × 10¹¹ to 1 × 10¹⁶. In this theoretical work, perovskite solar cells, including their absorbing layer, demonstrate outstanding ETLs and HTLs, respectively. As a result, the cells’ achieved PCE is improved. This work demonstrates the effectiveness of this lead-free double-perovskite structure that absorbs light in perovskite solar cells. Full article