Vacuum deposited perovskite solar cells employing dopant-free triazatruxene as the hole transport material

•Triazatruxene core as hole transport material for perovskite solar cells.•Extremely thin film (20 nm) can efficiently extract hole in perovskite solar cells.•Highly efficient devices can be fabricated using vacuum evaporation of triazatruxene as well as perovskites.

Planar perovskite solar cells using organic charge selective contacts were fabricated. In a vacuum deposited perovskite-based solar cell, dopant and additive free triazatruxene as the hole transport layer was introduced for device fabrication. High open-circuit voltage of 1090 mV was obtained using methylammonium lead iodide (Eg=1.55 eV) as light harvesting material, thus representing a loss of only 460 mV which is in close vicinity of mature silicon technology (400 mV). The devices showed a very competitive photovoltaic performance, monochromatic incident photon-to-electron conversion efficiency of 80% and the power conversion efficiencies in excess of 15% were measured with a negligible degree of hysteresis.