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Temperature-dependent photoluminescence (PL) spectroscopy measurements have been performed over a range from 9 K to room temperature on polycrystalline methylammonium (MA)/formamidinium (FA) lead iodide (MAFAPbI) perovskite thin films. Our low-temperature PL analysis reveals the existence of charge compensating defects in MAPbI, which may explain the lower net free carrier concentration in MAPbI perovskite. More interestingly, we observe the suppression of the PL emission associated with the charged defects by appropriate FA inclusion. Furthermore, FA incorporation into MAPbI has been found to slow the phase transformation of MAFAPbI from orthorhombic to tetragonal phase, which occurs with increasing temperature. Our analyses of the FA concentration's impact on defect density and structural phase transformation provide beneficial insights that improve the understanding of the photovoltaic properties and application of organic-inorganic metal halide perovskites.
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http://dx.doi.org/10.1021/acs.jpclett.9b03234 | DOI Listing |
Chem Sci
September 2025
College of Chemistry and Materials Engineering, Wenzhou University Wenzhou Zhejiang 325035 P. R. China
Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries (LIBs) owing to abundant resources and cost-effectiveness. However, cathode materials face persistent challenges in structural stability, ion kinetics, and cycle life. This review highlights the transformative potential of high-entropy (HE) strategies that leveraging multi-principal element synergies to address these limitations entropy-driven mechanisms.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, London WC1H 0AJ, U.K.
The exceptional performance of ceria (CeO) in catalysis and energy conversion is fundamentally governed by its defect chemistry, particularly oxygen vacancies. The formation of each oxygen vacancy (V) is assumed to be compensated by two localized electrons on cations (Ce). Here, we show by combining theory with experiment that while this 1 V: 2Ce ratio accounts for the global charge compensation, it does not apply at the local scale, particularly in nanoparticles.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
August 2025
Cardiff Catalysis Institute, School of Chemistry, Translational Research Hub, Cardiff University, Maindy Road, Cardiff CF24 4HF, U.K.
Controlling the formation of electron polarons in TiO doped with transition metals is important for the design of transparent conducting oxides for high-efficiency photovoltaics and photocatalysts with tunable reaction selectivities. In this work, EPR spectroscopy is combined with Hubbard-corrected density functional theory (DFT+), with refined atomic-like Hubbard projectors, to show the sensitivity of charge compensation in substitutionally doped Nb-TiO and W-TiO with respect to the TiO polymorph (, anatase or rutile). Both EPR magnetic tensors and DFT+predicted Nb 4 and W 5 orbital occupancies show the formation of differing dopant charge states depending on the TiO polymorph, with nonmagnetic Nb and W in doped anatase and paramagnetic Nb and W in doped rutile.
View Article and Find Full Text PDFbioRxiv
August 2025
Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany.
Brain aging is a major risk for neurodegeneration, yet the underlying molecular mechanisms remain poorly understood. Here we performed an integrative proteo-transcriptomic analysis of the aging mouse brain, uncovering molecular signatures of aging through the assessment of protein aggregation, mRNA relocalization, and comparative proteomics across eight models of premature aging and neurodegeneration. We identified dynamic changes in physiological aging highlighting differences in synaptic maintenance and energy-allocation.
View Article and Find Full Text PDFSci Rep
September 2025
Department of Chemistry, Isfahan University of Technology, Isfahan, 84156 - 83111, Iran.
Biomass has attracted considerable interest in the field of energy storage because of its outstanding characteristics, such as superior charge transport ability, affordability, eco-friendly, structural versatility, and renewability. Moreover, biomass-derived activated carbons, combined with pseudocapacitive materials, have recently gained popularity as efficient electrochemical components for energy storage devices. In this study, activated carbon was prepared from pinecone flowers as the biomass precursor through a process involving alkaline treatment and pyrolytic carbonization in an inert gas environment.
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