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Bulk Assembly of Corrugated 1D Metal Halides with Broadband Yellow Emission
摘要： The family of molecular level low-dimensional organic metal halide hybrids has expanded significantly over the last few years. Here a new type of 1D metal halide structure is reported, in which metal halide octahedra form a corrugated double-chain structure via nonplanar edge-sharing. This material with a chemical formula of C5H16N2Pb2Br6 exhibits a broadband yellow emission under ultraviolet light excitation with a photoluminescence quantum efficiency of around 10%. The light-yellow emission is considered to be attributed to self-trapping excitons. Theoretical calculations show that the unique alignment of the octahedra leads to small band dispersion and large exciton binding energy. Together with previously reported 1D metal halide wires and tubes, this new bulk assembly of 1D metal halides suggests the potential to develop a library of bulk assemblies of metal halides with controlled structures and compositions.
关键词： photoluminescence,quantum confinement effect,exciton self-trapping,organic metal halide hybrids,1D structures
更新于2025-09-23 15:22:29
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Low dimensional metal halide perovskites and hybrids
摘要： Organic-inorganic metal halide hybrids are an important class of crystalline materials with exceptional structural and property tunability. Recently metal halide perovskites with ABX3 structure have been extensively investigated as new generation semiconductors for various optoelectronic devices, including photovoltaic cells, light emitting diodes, photodetectors, and lasers, for their exceptional optical and electronic properties. By controlling the morphological dimensionality, low dimensional metal halide perovskites, including 2D perovskite nanoplatelets, 1D perovskite nanowires, and 0D perovskite quantum dots, have been developed to exhibit distinct properties from their bulk counterparts, due to quantum size effects. Besides ABX3 perovskites, organic-inorganic metal halide hybrids, containing the same fundamental building block of metal halide octahedra (BX6), can also be assembled to possess other types of crystallographic structures. Using appropriate organic and inorganic components, low dimensional organic-inorganic metal halide hybrids with 2D, quasi-2D, corrugated-2D, 1D, and 0D structures at the molecular level have been developed and studied. Due to the strong quantum confinement and site isolation, these low dimensional metal halide hybrids at the molecular level exhibit remarkable and unique properties that are significantly different from those of ABX3 perovskites. In light of the rapid development of low dimensional metal halide perovskites and hybrids, it is indeed timely to review the recent progress in these areas. Also, there is a need to clarify the difference between morphological low dimensional metal halide perovskites and molecular level low dimensional metal halide hybrids, as currently the terminologies of low dimensional perovskites are not appropriately used in many cases. In this review article, we discuss the synthesis, characterization, application, and computational studies of low dimensional metal halide perovskites and hybrids.
关键词： Optoelectronics,Halide Perovskites,Nanomaterials,Low dimensionality,Organic metal halide hybrids
更新于2025-09-23 15:19:57
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Phase Intergrowth and Structural Defects in Organic Metal Halide Ruddlesden–Popper Thin Films
摘要： Organic metal halide Ruddlesden?Popper layered perovskite phases combine the excellent optoelectronic properties of three-dimensional, bulk hybrid perovskites with superior material stability under ambient conditions. However, the thin film structure of these layered perovskites is still poorly understood, as phase purity is typically determined solely by specular X-ray diffraction. The thin film structure of these Ruddlesden?Popper phases was examined by increasingly local characterization techniques. From the comparison of grazing-incidence wide-angle X-ray scattering patterns of cast films to expected scattering from single-crystal structures, significant in-plane disorder was observed. Spatially localized photoluminescence measurements show that films do not phase separate on the micrometer scale. Selected area electron diffraction measurements show the intergrowth of different phases within the same thin film, consistent with previous observations seen in epitaxially grown Ruddlesden?Popper complex oxides. Despite the presence of phase impurities that would typically be detrimental for device performance, fits to photothermal deflection spectroscopy measurements show relatively low Urbach energies of 33 meV for (C4H9NH3)2(CH3NH3)2Pb3I10 and 32 meV for (C4H9NH3)2(CH3NH3)3Pb4I13, indicating that the electronic properties are insensitive to the phase impurities.
关键词： phase intergrowth,structural defects,Ruddlesden?Popper,thin films,Organic metal halide,perovskite
更新于2025-09-09 09:28:46