Wen Xiaoning, Cai Qingbing, Shen Guibin, Xu Xiangning, Dong Pei, Du Yaxin, Dong Hongye, Mu Cheng
Department of Chemistry, Renmin University of China, Beijing 1000872, People's Republic of China.
Nanotechnology. 2021 May 5;32(30). doi: 10.1088/1361-6528/abf5fa.
Perovskite crystal quality plays an important role in perovskite solar cells, given that multiple grain boundaries and trap states in the perovskite films hamper further enhancement of solar cell efficiency. Using the solution method to prepare perovskite films with large grains and high coverage requires further improvements. Herein, we introduce Lewis base urea as an additive into the precursor of perovskite to control the crystallization dynamics, allowing for large-grain crystal growth. As a result, MAPbIfilms with urea as an additive are well crystallized with large crystal grains of sizes >3m. The large-grain perovskite is found to simultaneously improve the power-conversion efficiency (PCE) and device stability. With an optimal urea additive of 20 mol%, the PCE is significantly increased from 15.47% for the reference MAPbIsolar cell to 18.53% for the device with MAPbIwith urea as an additive. Finally, the optimized device demonstrates excellent stability and maintains 80% of the initial PCE after 60 days.
鉴于钙钛矿薄膜中的多个晶界和陷阱态阻碍了太阳能电池效率的进一步提高，钙钛矿晶体质量在钙钛矿太阳能电池中起着重要作用。使用溶液法制备具有大晶粒和高覆盖率的钙钛矿薄膜需要进一步改进。在此，我们将路易斯碱尿素作为添加剂引入钙钛矿前驱体中，以控制结晶动力学，从而实现大晶粒晶体生长。结果，以尿素为添加剂的MAPbI薄膜结晶良好，具有尺寸大于3μm的大晶粒。发现大晶粒钙钛矿同时提高了功率转换效率（PCE）和器件稳定性。在尿素添加剂的最佳用量为20 mol%时，PCE从参考MAPbI太阳能电池的15.47%显著提高到以尿素为添加剂的MAPbI器件的18.53%。最后，优化后的器件表现出优异的稳定性，在60天后仍保持初始PCE的80%。
