Simultaneous Bulk and Surface Defect Passivation for Efficient Inverted Perovskite Solar Cells.

Abstract

Structural defects in the bulk and on the surface of the perovskite layer serving as trap sites induce nonradiative recombination losses, limiting the performance improvement of perovskite solar cells (PSCs). Herein, we report a trometamol-induced dual passivation (TIDP) strategy to fix both bulk and surface defects of perovskites, where the trometamol molecule can simultaneously act as chemical additive and surface-modification agent. Studies show that trometamol as an additive can effectively reduce ionic defects and enhance the grain size of perovskites through Pb2+/-NH2 coordination bonds and I-/-OH hydrogen bonds. As a surface-modification agent, trometamol further passivates ionic defects at the upper surface of the perovskite layer. As a result of the TIDP approach, a remarkable efficiency augmentation from 17.25% to 19.17% and an optimized thermal stability under inert conditions have been realized. These results highlight the importance of the TIDP strategy in perovskite defect management for excellent photovoltaic properties, facilitating the fabrication of high-performance PSCs.