Synergistic Fluorine⋅⋅⋅Sulfur Intra‐ and Intermolecular Interactions on Dopant‐Free Hole Transport Material for Efficient and Stable Inverted Perovskite Solar Cells

Abstract

Designing dopant‐free small‐molecule hole transport materials (HTMs) with self‐assembly behavior via noncovalent interactions is considered as one effective strategy to achieve high‐performance inverted perovskite solar cells (PSCs). Herein, two donor‐π bridge‐donor (D–π–D) HTMs are presented, TPASF and TPAOF, containing 3,6‐dimethoxythieno[3,2‐b]thiophene as a core part with 3‐fluoro‐N,N‐bis(4‐(methylthio)phenyl)aniline and 3‐fluoro‐N,N‐bis(4‐methoxyphenyl)aniline as side group. The synergistic F⋅⋅⋅S dipole–dipole intra‐ and intermolecular interactions in TPASF drive the self‐assembly of this molecule into a supramolecular nanofibrillar network, leading to high hole mobility, superior interfacial properties, and providing a good growth template for the perovskite layer atop. The corresponding dopant‐free TPASF‐based inverted devices exhibit a promising power conversion efficiency of 21.01% with a long T 80 lifetime of ≈632 h under operational conditions. This work paves the way for the further development of new dopant‐free self‐assembled HTM designs for highly efficient and stable inverted PSCs.