光致发光
量子产额
材料科学
掺杂剂
兴奋剂
结构精修
钙钛矿(结构)
正交晶系
晶格常数
分析化学(期刊)
结晶学
光电子学
化学
晶体结构
衍射
光学
物理
有机化学
荧光
作者
Baidyanath Roy,Somnath Mahato,Shaona Bose,Arup Ghorai,S. K. Srivastava,Narayan Chandra Das,S. K. Ray
标识
DOI:10.1021/acs.chemmater.2c03095
摘要
The synthesis of air-stable and cubic phases of all-inorganic halide perovskite nanocrystals (HPNCs) by a hot-injection approach is still challenging due to their rapid in situ phase transformations. Therefore, understanding and preventing this phase conversion by doping of cations is the key to improve the structural stability, environmental durability, and photoluminescence quantum yield. Here, the doping of divalent Cu ions at the Pb-site of cesium lead iodide (CsPbI3) is reported to achieve cubic-phase (α-phase) HPNCs with superior quantum yield and enhanced stability compared to undoped CsPbI3. Rietveld refined X-ray diffraction patterns and atomic-resolution transmission electron microscopy analyses reveal structural transformation from a mixed (γ-orthorhombic and α-cubic) phase to a cubic (α-CsPbI3) one with a smaller lattice constant at an optimal (5.6%) Cu concentration. Computational density functional theory (DFT) analysis credits the resultant structural and environmental stability for the Cu-doped sample to the charge accumulation at the dopant site that leads to increased bond strength with consequent minimization of the energy of the system to give rise to the maximum stability of the HPNCs at this dopant ratio. With the increase of Cu-doping, a red shift is observed in the absorbance and photoluminescence spectra up to a critical doping level, making the system optically tuneable. The optimally doped (5.6% Cu) CsPbI3 HPNCs exhibit stronger light emission with higher carrier lifetime and higher quantum yield (>80%), which are absolutely essential requirements in air-stable optoelectronic devices.
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