Localized Transporting Channel through Nanoscale Phase Separation for Efficient Inverted Perovskite Solar Cells

Abstract

Interfacial recombination at perovskite/PCBM interface is a critical factor for efficiency loss in inverted perovskite solar cells (PSCs). Different to commonly used fully covered PCBM transporting layer, here we develop a localized electron transporting channel to reduce perovskite/PCBM direct contact area by introducing nanoscale separated PM6:PCBM. In this structure, electrons cannot be transported throughout PM6. However, these electrons can circumvent PM6 and be extracted by PCBM due to the bi-continuous and nanoscale phase separation in PM6:PCBM, which will effectively reduce the contact area between perovskite and PCBM, thus inhibiting interfacial recombination. Resulting PSCs exhibit efficiency of 25.80% with high FF of over 84%, and the stability is also improved with 93.1% of initial efficiency after 65 ^oC aging for 2000 h.