[6,6]-Phenyl-C<sub>61</sub>-Butyric Acid Methyl Ester/Cerium Oxide Bilayer Structure as Efficient and Stable Electron Transport Layer for Inverted Perovskite Solar Cells.

Fang, Rui; Wu, Shaohang; Chen, Weitao; Liu, Zonghao; Zhang, Shasha; Chen, Rui; Yue, Youfeng; Deng, Linlong et al. · ACS Nano · 2018

basic_science · Level V

Where this comes from

Abstract

Stability issues and high material cost constitute the biggest obstacles of a perovskite solar cell (PVSC), hampering its sustainable development. Herein, we demonstrate that, after suitable surface modification, the low-cost cerium oxide (CeO <sub>x</sub>) nanocrystals can be well dispersed in both polar and nonpolar solvents and easily processed into high-quality electron transport layers (ETLs). The inverted PVSC with the configuration of "NiMgLiO/MAPbI<sub>3</sub>/[6,6]-phenyl-C<sub>61</sub>-butyric acid methyl ester (PCBM)/CeO <sub>x</sub>" has achieved a high efficiency up to 18.7%. Especially, the corresponding devices without encapsulation can almost keep their initial PCEs in 30% humidity-controlled air in the dark for 30 days and also show no sign of degradation after continuous light soaking and maximum power point tracking for 200 h in a N<sub>2</sub> atmosphere. These results have been proved to be associated with the dual functions achieved by the PCBM/CeO <sub>x</sub> bilayer ETLs in both efficient electron extraction and good chemical shielding. Furthermore, an all inorganic interfacial layer based PVSC with the configuration of "NiMgLiO/MAPbI<sub>3</sub>/CeO <sub>x</sub>" has also achieved a promising efficiency of 16.7%, reflecting the potential to fabricate efficient PVSCs with extremely low cost.