Homogenizing SAMs deposition via seeding -OH groups for scalable fabrication of perovskite solar cells

Abstract

Self-assembled monolayers (SAMs) play the significant roles in the rapidly-progressed inverted perovskite solar cells (PSCs). Additional metal oxide or molecular incorporations are widely adopted to ameliorate their incomplete and uneven depositions on substrates, where the underlying binding situations between SAMs and substrates are vital for further optimizations but unclear. Here, we compare the bonding types between SAMs and metal oxides from a theoretical view, and conclude that SAMs preferably form the strong chemical bonds of -P-O-Sn via reacting with hydroxyl groups (-OH) on metal oxides for solid adsorptions. We further proposed the easy but effective strategy named seeding-OH groups via hydrogen peroxide(H2O2)/ultraviolet bath to strength and homogenize SAMs deposition on substrates, yielding the superior buried interface contact and high-quality perovskite films. Integrating the benefits, the resulted PSCs realized the champion efficiency of 26.19%, and 24.68% and 21.77% during their scalable fabrications with the areas of 1.21 and 13.8 cm2 (minimodules, active area), surpassing the bare ones with inferior scalability. Moreover, the large-area devices remained over 90% of their initial efficiency after ISOS-L-3 test for 1000 h.