溶剂退火处理空穴传输层对改善钙钛矿电池性能的研究

近年来,基于CH_3NH_3PbX_3(X=Cl,Br,I)材料的钙钛矿太阳能电池发展迅速。控制钙钛矿电池中每一层的形貌对于提高电池性能的影响至关重要。使用溶剂退火的方法处理空穴传输层(spiro-OMeTAD),使其表面形貌更加平整均匀,从而改善了空穴传输层与金属电极的接触,减小了电阻,更加有利于电子的传输和收集。使用氯仿进行溶剂退火以后,钙钛矿电池光电转化效率从原来的11.3%提高到了13.1%。其中开路电压、短路电流密度、和填充因子均有大幅提高。电池的迟滞现象从原来的8.8%减小到1.5%。经过长时间测试,使用溶剂退火以后的电池稳定性也有明显改善。研究论证了溶剂退火处理空穴传输层对于制备高性能、低迟滞、更稳定的钙钛矿太阳能电池具有至关重要的作用。

A Study on Solvent Vapor Annealing of Hole Transport Layer for Improving the Performance of Perovskite Solar Cells

Recently, CH3NH3PbX3 (X=Cl, Br, or I) based perovskite solar cells (PSCs) have been very rapidly developed. Control the morphology of each layer in PSCs plays very important roles for improving the performance of PSCs. In this work, we reported the use of chloroform based solvent vapor annealing (VA) method to control the morphology of hole transport layer (spiro-OMeTAD) of PSCs. After treated by solvent VA, the morphology of spiro-OMeTAD layer became smoother and more uniform, which is beneficial for improving the interface and reducing the contact resistance of PSCs. By using solvent VA for spiro-OMeTAD layer, the power conversion efficiency of PSCs was improved from 11.3% to 13.1%, with open circuit voltage, short circuit current density and fill factor enlarged simultaneously. Hysteresis was dramatically reduced from 8.8% to 1.5% upon using solvent VA. Moreover, the long term stability of the PSCs was also improved. Our investigation indicates that using solvent VA for spiro-OMeTAD layer treatment is very important for fabricating high performance, low hysteresis and stable PSCs.