Fully Vacuum-Processed Wide-Bandgap p-i-n Perovskite Solar Cells Enabled by p-Doped Hole-Transport Layers

Abstract

Fully vacuum-deposited perovskite solar cells provide an alternative approach to overcome the limitations of solution- based processing, such as incomplete film coverage and challenges in large-area fabrication. In this dissertation, a unified dry-process strategy is presented that integrates precise composition engineering of wide-bandgap perovskites with vacuum-deposited, molecularly p-doped small-molecule hole-transport layers. In Chapter 1, a calibrated co-evaporation strategy based on a reference-material calibration method is established to fabricate uniform and compositionally stable perovskite thin films with large grain size and favorable optoelectronic properties. This strategy enables precise control over the deposition process, leading to highly reproducible vacuum- processed perovskite solar cells with a power conversion efficiency of up to 21%. In Chapter 2, the molecular p-doping behavior of vacuum-deposited hole-transport layers (HTLs) is investigated with an emphasis on the relationship between charge-transfer (CT) complex formation and dopant ionization efficiency. Under NDP-9 doping, p-doped TaTm exhibits the highest ionization efficiency among the candidate HTLs, which improves energy-level alignment and suppresses nonradiative recombination, leading to enhancements in open-circuit voltage and fill factor. The fully vacuum-based process supports continuous deposition and large-area manufacturing, enabling industrially scalable perovskite and tandem cells.