Shao Feng, Qin Peng, Wang Dong, Zhang Guoqing, Wu Bo, He Jianqiao, Peng Wei, Sum Tze Chien, Wang Deliang, Huang Fuqiang
State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics , Chinese Academy of Sciences , Shanghai 200050 , China.
Hefei National Laboratory for Physical Sciences at the Microscale , University of Science and Technology of China , Hefei 230026 , China.
ACS Appl Mater Interfaces. 2019 Jan 9;11(1):740-746. doi: 10.1021/acsami.8b17068. Epub 2018 Dec 20.
The organic-inorganic lead halide perovskites are attractive materials for photovoltaic application. The most widely studied perovskites based on methyl ammonium organic cation are less likely to form an ideal high-symmetry configuration at room temperature, leading to the appearance of local lattice strain. Herein, this study reports a strategy for the construction of thermally stable cubic perovskites at room temperature through the incorporation of the larger organic cation dimethyl ammonium. Detailed characterization on the single crystals and thin films reveals the formation of cubic phase with the addition of a certain amount of dimethyl ammonium at room temperature. With the presence of dimethyl ammonium, the nonradiative recombination in perovskite is suppressed, showing a longer PL lifetime and hole diffusion length. The more efficient charge extraction leads to an improvement in the photocurrent density, and then the device efficiency from 17.1% to 18.6%, together with an enhanced thermal stability at 85 °C. The influence of incorporating a larger organic cation on the structural configuration, optical properties, charge extraction, as well as the photovoltaic performance is systematically investigated, which offers an alternative way to improve the intrinsic stability of hybrid perovskites.
有机-无机卤化铅钙钛矿是用于光伏应用的有吸引力的材料。基于甲铵有机阳离子的最广泛研究的钙钛矿在室温下不太可能形成理想的高对称构型，导致出现局部晶格应变。在此，本研究报告了一种通过引入较大的有机阳离子二甲铵在室温下构建热稳定立方钙钛矿的策略。对单晶和薄膜的详细表征揭示了在室温下添加一定量的二甲铵时立方相的形成。在二甲铵存在下，钙钛矿中的非辐射复合受到抑制，显示出更长的光致发光寿命和空穴扩散长度。更有效的电荷提取导致光电流密度提高，进而使器件效率从17.1%提高到18.6%，同时在85°C下热稳定性增强。系统地研究了引入较大有机阳离子对结构构型、光学性质、电荷提取以及光伏性能的影响，这为提高混合钙钛矿的固有稳定性提供了一种替代方法。
