A new polytriarylamine derivative for dopant-free high-efficiency perovskite solar cells†
The development of dopant-free organic charge transport layers is crucial for achieving long-term stability of perovskite solar cells. In this paper, we present a new polytriarylamine derivative, poly[bis(4-phenyl)(4-methylphenyl)amine] (PTA), which showed significantly improved photovoltaic performance compared to dopant-free PTAA. Perovskite solar cells based on the PTA/MoO3 hybrid hole-transport layer (HTL) and MAPbI3 absorber delivered a competitive 17.0% efficiency, which is currently the highest value achieved for n–i–p perovskite solar cells using dopant-free polytriarylamine-type HTLs. The enhanced device performance was attributed to a better HOMO alignment of PTA (5.38 eV) vs. PTAA (5.27 eV) with respect to the perovskite valence band.