新型准二维钙钛矿太阳能电池材料

Metal halide perovskites exhibit outstanding photovoltaic properties due to their superior charge carrier mobilities, low densities of deep trap states, and low-temperature solution processability. The introduction of bulky organic cations, causing the formation of quasi-two-dimensional perovskite structures, makes up the average dimensionally tuned perovskite in a solid-state material could be used as a means to enhance the materials stability against irradiation, heat, and moisture. However, the widely-used organic cations, such as phenylethylammonium and butylammonium, are intrinsically non-conductive. The integration of such organic cation therefore impairs the carrier separation and transport within the quasi-two-dimensional perovskite active layer. Here we propose to improve the carrier mobility of the quasi-two-dimensional perovskites by introducing new classes of bulky conjugated organic cations. Combining the experience of organic, inorganic, and surface chemistry, we design organic cations that can (1) interact with perovskite precursors to yield uniform perovskite crystals, (2) have strong intermolecular interaction with each other during crystallization, and thus improve the packing of organic cations and promote the carrier transport between two adjacent perovskite grains. We will carry out systematic chemical and photophysical studies to deepen our understanding of this new class of perovskites, which will be further applied to the fabrication of highly efficient and stable solution-processed photovoltaics.

由于其优异的载流子迁移率、较低的深电学陷阱密度以及优秀的低温溶液可加工特性，金属卤化物钙钛矿材料表现出极为优秀的光伏特性。通过引入体积较大的有机正离子能形成准二维钙钛矿结构，并以此调整固态钙钛矿材料的维度尺寸来实现材料对光、热、和湿度的稳定性提升。然而目前已有的有机阳离子如苯乙基铵和丁基铵导电能力不佳。 因此，当整合这些有机阳离子而形成准二维钙钛矿时会对材料中的载流子输运和分离性能带来影响。在此项目中我们提出通过引入新型的较大体积的共轭有机阳离子去改善载流子迁移率。通过结合有机化学、无机化学和表面化学的研究经验，我们设计新型的有机阳离子可以(1)与其他钙钛矿前驱体产生相互作用以改善有机阳离子间的相互作用，从而生成均匀准二位钙钛矿;(2)在结晶过程中利用分子间相互作用来改善有机阳离子排列状况并以此改善微晶间的电荷传输性能。我们会以此为基础制作高性能高稳定性的太阳能电池。

金属卤化物钙钛矿材料具有表现出极为优秀的光伏特性。通过引入体积较大的有机正离子能形成准二维钙钛矿结构，并以此调整固态钙钛矿材料的维度尺寸来实现材料对光、热、和湿度的稳定性提升。然而目前已有的有机阳离子如苯乙基铵和丁基铵导电能力不佳。因此在本项目中，我们开拓了一系列新型的有机阳离子钙钛矿配体和相应的结构，通过引入新型的较大体积的共轭有机阳离子去改善载流子迁移率，从而提高器件的能量转换效率。与此同时，我们成功实现了四种有机阳离子配体原位转换的方法，并一次为基础发展出数种新型的低维钙钛矿结构。