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 ((CH 3 ) 3 SI) 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 (CH 3 ) 3 SI and Pb 2+ to inhibit the production of Pb 0 . Importantly, the 1D (CH 3 ) 3 SPbI 3 seeding layer can promote perovskite crystallization, improve NiO x 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 cm 2 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 ℃.