Self-Assembled Hole-Transporting Materials with Backbone Isomerization Strategy toward Inverted Perovskite Solar Cells: From Theoretical Design to Experiment.

Nonradiative recombination losses at the interface is a critical bottleneck limiting the performance of perovskite solar cells (PSCs). Self-assembled hole-transporting materials (SA-HTMs) can effectively suppress such recombination, playing a vital role in enhancing device performance. We propose a site-isomeric strategy by introducing dibenzofuran groups into the carbazole unit to design a series of SA-HTMs (DF1CA-DF4CA), from which the most promising molecule was screened via theoretical calculations and subsequently synthesized in a targeted manner. In these designed molecules, theoretical simulated results indicate that DF4CA possesses a conjugated backbone with superior planarity, which can enhance its hole transport ability, interfacial adsorption, and packing density on the ITO substrate, thereby effectively suppressing interfacial nonradiative recombination. Ultimately, the DF4CA-based device achieved a power conversion efficiency of 25.68%, surpassing that of the control device (23.72%), validating the effectiveness of this strategy in regulating interfacial nonradiative recombination and enhancing device performance.