Multifunctional one-dimensional seeding layers enable stable and over 20%-efficiency inverted perovskite photovoltaic modules

Perovskite solar cells exhibit one of the most noticeable photovoltaic technologies; however, the buried defects under perovskite films reduce both power conversion efficiency (PCE) and long-term stability, particularly in large-area modules. Reasonable seeding layers can address the above issues to achieve stable and effective perovskite photovoltaic devices. Herein, trimethylsulfide iodine ((CH3)3SI) was utilized to passivate the buried interface and act as one-dimensional (1D) seeding mediator to regulate the air-processed perovskite growth for inverted photovoltaic module with high stability and over 20% efficiency. The strong interaction Pb-S bond is formed between (CH3)3SI and Pb2+ to inhibit the production of Pb0. Importantly, the 1D (CH3)3SPbI3 seeding layer can promote perovskite crystallization, improve NiOx conductivity for hole transfer, optimize energy level arrangement to reduce interfacial band offset, and improve open-circuit voltage. As a result, the PCE of inverted photovoltaic modules based on 10.0 × 10.0 cm2 substrate was significantly improved from 18.47% to 20.03%. Meanwhile, the optimized device module without encapsulation maintained over 85% of the original PCE value during 1000 h storing under 40–60% humidity and 30–36 ℃.