Single-crystalline TiO2 Nanoparticles for Narrowing the Scalability Gap towards Stable and Efficient Perovskite Modules

Abstract Remarkable progress in power conversion efficiency of perovskite solar cells (PSCs) has been achieved over the last decade, reaching 25.5%. However, transferring these accomplishments from individual small-size devices into large-area modules while preserving their commercial competitiveness compared to other thin-film solar cells remains a challenge. A major obstacle is to reduce the resistive losses and the number of intrinsic defects of electron transport layers (mesoporous TiO2, ETL) and to fabricate high-quality large-area perovskite films. Here, we report a facile solvothermal method to synthesize single-crystalline TiO2 rhombus-like nanoparticles with exposed {001} facets. Owing to their low lattice mismatch with the perovskite absorber, high electron mobility and lower density of defects, single-crystalline TiO2 nanoparticle-based small-size devices (0.09 cm2) achieve an efficiency of 24.05% and a fill factor of 84.7%. Importantly, these devices maintain about 90% of their initial performance after continuous operation for 1400 h. Combined with vacuum quenching-assisted techniques, we have fabricated large-area modules and obtained a certified efficiency of 22.72% with an active area of nearly 24 cm2. This represents the highest efficiency modules with the lowest efficiency loss between small-size devices and modules, enabling to reproducibly fabricate stable and efficient PSC modules.