Improving efficiency and stability of inverted perovskite solar cells using C60/PTCDA binary electron transport layer

Abstract

Herein, we explored the application of perylenetetracarboxylic dianhydride (PTCDA) electron transport material for inverted perovskite solar cells (PSCs). We obtained a modest power conversion efficiency (PCE) of 15.0 % using PTCDA alone to form electron-transport layer (ETL) of p-i-n devices, whereas the combination of PCTDA with C₆₀ within a binary ETL delivered PCE of 19.8 %. The improved efficiency reached with binary ETL can be attributed to its ability to facilitate charge transfer and passivate traps the surface of the perovskite layer thus reducing recombination losses at the absorber/ETL interface. Further insights were provided by IR s-SNOM microscopy, which revealed that the binary C₆₀/PTCDA ETL has a highly uniform and homogeneous structure with low density of defects and pinholes, thus ensuring effective isolation of MAPbI₃ and effective operation of PSCs. Moreover, the binary C₆₀/PTCDA ETL improved the stability of PSCs under ambient conditions, so the devices exhibited no signs of degradation after 1000 h. These findings feature the potential of PTCDA as a promising organic component for designing engineered multicomponent ETLs for improving the performance and stability of PSCs.