The extended charge carrier lifetime in metal halide perovskites is responsible for their excellent optoelectronic properties. Recent studies indicate that the superb device performance in these materials is intimately related to the organic cation dynamics. Here, we focus on the investigation of the two-dimensional hybrid perovskite, (CHNH)PbI (henceforth, OA = CHNH ). Using elastic and quasielastic neutron scattering techniques and group theoretical analysis, we studied the structural phase transitions and rotational modes of the CHNH cation in (OA)PbI. Our results show that, in the high-temperature orthorhombic (T > 310 K) phase, the OA cation exhibits a combination of a twofold rotation of the NH-CH head group about the crystal c-axis with a characteristic relaxation time of ∼6.2 ps, threefold rotations (C) of NH and CH terminal groups, and slow librations of the other atoms. Contrastingly, only the C rotation is present in the intermediate-temperature orthorhombic (238 K < T < 310 K) and low-temperature monoclinic (T < 238 K) phases.
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Chem Asian J
January 2025
Towson University, 8000 York Road, SC 3301B, 21252, Towson, UNITED STATES OF AMERICA.
Au nanoclusters often demonstrate useful optical properties such as visible/near-infrared photoluminescence in addition to remarkable thermodynamic stability owing to their superatomic behavior. The smallest of the 8e- superatomic Au nanoclusters, Au11, has limited applications due to its lack of luminescence and relatively low stability. In this work, we investigate the introduction of a single Pt dopant to the center of a halide- and triphenylphosphine-ligated Au11 nanocluster, obtaining a cluster with a proposed molecular formula PtAu10(PPh3)7Br3.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Key Laboratory for High Efficiency Energy Conversion Science and Technology of Henan Province, International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, School of Physics and Electronics, Henan University, Kaifeng, 475004, P. R. China.
Multimode luminescent materials exhibit tunable photon emissions under different excitation or stimuli channels, endowing them high encoding capacity and confidentiality for anti-counterfeiting and encryption. Achieving multimode luminescence into a stable single material presents a promising but remains a challenge. Here, the downshifting/upconversion emissions, color-tuning persistent luminescence (PersL), temperature-dependent multi-color emissions, and hydrochromism are integrated into Er ions doped CsNaYbCl nanocrystals (NCs) by leveraging shallow defect levels and directed energy migration.
View Article and Find Full Text PDFACS Sens
January 2025
State Key Laboratory of Materials Processing and Die Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), No. 1037, Luoyu Road, Wuhan 430074, P. R. China.
High selectivity and sensitivity sensing of HS gas play a decisive role in the early detection of sulfide solid-state battery failure. Herein, we construct the CsPbBr perovskite-based sensor that exhibits outstanding gas-sensing performance to HS at room temperature, including high selectivity, fast response/recovery speed (73.5/275.
View Article and Find Full Text PDFChem Soc Rev
January 2025
School of Science, RMIT University, Melbourne, 3000, Australia.
Metal halide perovskites (MHPs) have emerged as the most promising materials due to superior optoelectronic properties and great applications spanning from photovoltaics to photonics. Absorption spectroscopy provides a broad and deep insight into the carrier dynamics of MHPs, and is a critical complement to fluorescence and scattering spectroscopy. However, absorption spectroscopy is often misunderstood or underestimated, being seen as UV-vis spectroscopy only, which can lead to various misinterpretations.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Fribourg Faculty of Science: Universite de Fribourg Faculte de sciences et de medecine, Adolphe Merkle Institue, Chemin des Verdiers 4, 1700, Fribourg, SWITZERLAND.
Metal halide perovskites have shown exceptional potential in converting solar energy to electric power in photovoltaics, yet their application is hampered by limited operational stability. This stimulated the development of hybrid layered (two-dimensional, 2D) halide perovskites based on hydrophobic organic spacers, templating perovskite slabs, as a more stable alternative. However, conventional organic spacer cations are electronically insulating, resulting in charge confinement within the inorganic slabs, thus limiting their functionality.
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