An Alternative to Chlorobenzene as a Hole Transport Materials Solvent for High-Performance Perovskite Solar Cells

Spiro-OMeTAD is a widely used hole-transporting layer (HTL) material, characterized by high hole mobility and good film-forming properties, in perovskite solar cells (PSCs). However, this material has high synthesis costs, low solubility, dependence on hygroscopic dopants, and a low commercial potential. Recently, we investigated alternative materials with good solubility, simple synthetic methods, and good electrical characteristics for use as hole transport materials (HTM) in triple-cation PSCs. Herein, (E,E,E,E)-4,4 ',4 '',4 '''-[Benzene-1,2,4,5-tetrayltetrakis(ethene-2,1-diyl)]tetrakis[N,N-bis(4-methoxyphenyl)aniline], which has a small molecular weight and similar properties to Spiro-OMeTAD, was assessed for use as a HTM via a pre-test of device performance, including its electrical properties, surface morphology, and coating process method, with PSC efficiencies routinely surpassing 20%. A remarkable open-circuit voltage of 1.111, along with a photovoltaic efficiency of 20.18% was obtained in PSCs using this HTM with dichloromethane (DCM) instead of chlorobenzene, indicative of its potential for the fabrication of resistance components with improved surface uniformity. These results provide insights into DCM as an efficient solvent for small molecule-based HTM.