Perovskite Grains Embraced in a Soft Fullerene Network Make Highly Efficient Flexible Solar Cells with Superior Mechanical Stability
Meng Li, Ying-Guo Yang, Zhao-Kui Wang,* Tin Kang, Qiong Wang, Silver-Hamill Turren-Cruz, Xing-Yu Gao, Chain-Shu Hsu, Liang-Sheng Liao,* and Antonio Abate*
1Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-AiRoad, Suzhou 215123, China.
2Helmholtz-Zentrum Berlin für Materialien und Energie Kekuléstraße 5, 12489 Berlin, Germany
3Shanghai Synchrotron Radiation Facility (SSRF), Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 239 Zhangheng Road, Shanghai 201204, P. R. China
4Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan
5Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
6Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, Fuorigrotta, 80125 Naples, Italy
Halide perovskite films processed from solution at low temperature offer promising opportunities to make flexible solar cells. However, the brittleness of perovskite films is an issue for mechanical stability in flexible devices. Herein, photo-crosslinked [6,6]-phenylC61-butyric oxetane dendron ester (C-PCBOD) is used to improve the mechanical stability of methylammonium lead iodide (MAPbI3) perovskite films. Also, it is demonstrated that C PCBOD passivates the grain boundaries, which reduces the formation of trap states and enhances the environmental stability of MAPbI3. Thus, MAPbI3 perovskite solar cells are prepared on solid and flexible substrates with record efficiencies of 20.4% and 18.1%, respectively, which are among the highest ever reported for MAPbI3 on both flexible and solid substrates. The result of this work provides a step improvement toward stable and efficient flexible perovskite solar cells.