Unveiling enhanced hole transfer mechanism in perovskite solar cells with a self-assembled monolayer and [1]benzothieno[3,2-b][1]benzothiophene interlayer

Abstract

With exceptional photoconversion efficiencies, Perovskite Solar Cells (PSCs) are shaping the future of next-generation photovoltaics. Their performance and stability critically depend on the interfaces between the photoactive perovskite and charge transport layers. Incorporating interlayer materials to fine-tune these interfacial properties has significantly improved both efficiency and durability, yet the mechanisms driving these effects remain poorly understood. In this work, we use advanced computational methods based on density functional theory to investigate the role of a C10-BTBT interlayer between a triple-cation perovskite and the widely used MeO-2PACz. Our results uncover, for the first time, a bridge-mediated charge transfer mechanism, demonstrating how C10-BTBT not only strengthens interfacial chemical interactions, but also plays a key role in accelerating hole injection. These novel insights provide a molecular-level understanding of interlayer contributions and establish a robust and versatile framework, broadly applicable to the design and optimization of PSC interfaces for enhanced efficiency and durability.