Scalable All-Vacuum-Processed Perovskite Solar Cells Enabled by Low Energy-Disorder Hole-Transport Layer

As perovskite solar cells (PSCs) require higher standards for commercial applications, all vacuum-processed PSCs should become a key in future manufacturing processes of scalable PSCs compared to their currently dominating research types based on solution processes. In fact, vacuum deposition of high-quality organic hole-transport layers (HTLs) is crucial for successful fabrication of all vacuum-processed scalable PSCs. Here, the study develops a triarylamine-based single oligomer (TAA-tetramer)−a miniaturized-molecular form of the well-known poly(triarylamine) (PTAA)−as a vacuum-processable HTL in inverted PSCs. The well-defined structure and monodisperse nature of the TAA-tetramer render strong intermolecular π−π interactions and/or molecular ordering, resulting in simultaneously enhanced quasi-Fermi level splitting and hole-transport efficiency of the perovskite. The resulting all-vacuum-processed inverted PSCs exhibits a high power conversion efficiency (PCE) of 23.2%, which is record-high performance reported among all-vacuum-processed PSCs, with exceptional device stabilities. Furthermore, the all-vacuum-deposition process allows the fabrication of efficient PSCs and modules with reliable scalability and minimized efficiency loss during scale-up. Notably, the proposed HTL enabled high-efficiency large-area (25 cm²) single-PSC with a PCE of 12.3%, representing one of the largest active areas and the highest performance ever reported for the large-area device. A promising strategy for developing efficient, stable, and scalable PSCs for all-vacuum processes is presented.