Qiao Wen-Cheng, Dong Wei, Fu Xiao-Bin, Ma Kaiyang, Liang Jia-Qi, Wang Xue Lu, Yao Ye-Feng
Physics Department and Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, North Zhongshan Road 3663, Shanghai 200062, P. R. China.
Department of Molten Salt Chemistry and Engineering, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
J Phys Chem Lett. 2021 Nov 18;12(45):11206-11213. doi: 10.1021/acs.jpclett.1c03095. Epub 2021 Nov 11.
Considerable progress has been made in improving the performance of optoelectronic devices based on hybrid organic-inorganic perovskites of the form ABX. However, the influences of A-site doping on the structure and dynamics of the inorganic perovskite crystal lattice and, in turn, on the optoelectronic performance of the resulting devices remain poorly understood at an atomic level. This work addresses this issue by combining the results of several experimental characterization methods for three-dimensional MADMAPbBr perovskite single crystals (MA, methylammonium; DMA, dimethylammonium). The results reveal a two-stage change in lattice with an increase in DMA content, which has completely opposite effects on the optoelectronic performance of the double-cation perovskite. At low DMA concentrations, fast reorientation of incorporated DMA cations strengthens the interaction between MA cations and the lattice without significant lattice distortion, which could suppress lattice fluctuation and thus improve the photovoltaic performance. At high DMA concentrations, the lattice get a severe distortion, leading to poorer photovoltaic performance.
在提高基于ABX型混合有机-无机钙钛矿的光电器件性能方面已经取得了相当大的进展。然而，A位掺杂对无机钙钛矿晶格结构和动力学的影响，进而对所得器件的光电性能的影响，在原子水平上仍知之甚少。这项工作通过结合对三维MADMAPbBr钙钛矿单晶（MA，甲铵；DMA，二甲铵）的几种实验表征方法的结果来解决这个问题。结果表明，随着DMA含量的增加，晶格发生两阶段变化，这对双阳离子钙钛矿的光电性能产生了完全相反的影响。在低DMA浓度下，掺入的DMA阳离子的快速重新取向增强了MA阳离子与晶格之间的相互作用，而不会产生明显的晶格畸变，这可以抑制晶格波动，从而提高光伏性能。在高DMA浓度下，晶格会发生严重畸变，导致光伏性能变差。
