Organic metal halide hybrids with low-dimensional structures at the molecular level have received great attention recently for their exceptional structural tunability and unique photophysical properties. Here we report for the first time the synthesis and characterization of a one-dimensional (1D) organic metal halide hybrid, which contains metal halide nanoribbons with a width of three octahedral units. It is found that this material with a chemical formula C 8 H 28 N 5 Pb 3 Cl 11 shows a dual emission with a photoluminescence quantum efficiency (PLQE) of around 25%. Photophysical studies and density functional theory (DFT) calculations suggest the coexisting of delocalized free excitons and localized self-trapped excitons in metal halide nanoribbons leading to the dual emission.
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Abstract Scintillation based X-ray detection has received great attention for its application in a wide range of areas from security to healthcare. Here, we report highly efficient X-ray scintillators with state-of-the-art performance based on an organic metal halide, ethylenebis-triphenylphosphonium manganese (II) bromide ((C38H34P2)MnBr4), which can be prepared using a facile solution growth method at room temperature to form inch sized single crystals. This zero-dimensional organic metal halide hybrid exhibits green emission peaked at 517 nm with a photoluminescence quantum efficiency of ~ 95%. Its X-ray scintillation properties are characterized with an excellent linear response to X-ray dose rate, a high light yield of ~ 80,000 photon MeV−1, and a low detection limit of 72.8 nGy s−1. X-ray imaging tests show that scintillators based on (C38H34P2)MnBr4powders provide an excellent visualization tool for X-ray radiography, and high resolution flexible scintillators can be fabricated by blending (C38H34P2)MnBr4powders with polydimethylsiloxane.
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Metal-halide perovskites, in particular their nanocrystal forms, have emerged as a new generation of light-emitting materials with exceptional optical properties, including narrow emissions covering the whole visible region with high photoluminescence quantum efficiencies of up to near-unity. Remarkable progress has been achieved over the last few years in the areas of materials development and device integration. A variety of synthetic approaches have been established to precisely control the compositions and microstructures of metal-halide perovskite nanocrystals (NCs) with tunable bandgaps and emission colors. The use of metal-halide perovskite NCs as active materials for optoelectronic devices has been extensively explored. Here, we provide a brief overview of recent advances in the development and application of metal-halide perovskite NCs. From color tuning via ion exchange and manipulation of quantum size effects, to stability enhancement via surface passivation, new chemistry for materials development is discussed. In addition, processes in optoelectronic devices based on metal-halide perovskite NCs, in particular, light-emitting diodes and radiation detectors, will be introduced. Opportunities for future research in metal-halide perovskite NCs are provided as well.more » « less
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The photophysical properties of square planar Pt(II) complexes are often strongly dependent on their self‐assembly modes and intermolecular Pt⋯Pt interactions. Controlling these interactions is important to achieve valuable properties for various applications, such as light‐emitting diodes and environmental sensing devices. Herein, a series of highly luminescent ionic Pt(II) complexes with tunable emission colors are reported, by controlling the molecular structures and interactions in solid state. Four ionic Pt(II) complexes, with a general formula [Pt(C^N)(N^N)]+X−(C^N = 2‐phenylpyridine or 2‐(2,4‐difluorophenyl)pyridine; N^N = 2,2′‐bipyridine; X−= chloride (Cl−) or tetraphenylborate (BPh4−), are designed, synthesized, and characterized. Due to the presence of intermolecular Pt⋯Pt interactions, strong metal–metal‐to‐ligand charge transfer (MMLCT) emissions are recorded in all four complexes with color changing from green to deep red in solid state. A high photoluminescence quantum efficiency (PLQE) of 81% is achieved for one of the complexes containing large BPh4−anions, due to the site isolation effects. Detailed structural and photophysical characterizations reveal a clear correlation between the stacking of these Pt(II) complexes and their photophysical properties, which can be well regulated by the molecular structures and counter‐anions.
