Stabilizing hybrid perovskites against moisture and temperature via non-hydrolytic atomic layer deposited overlayers

Abstract

A novel non-hydrolytic (nh) surface chemistry is utilized to allow the direct synthesis of pinhole-fee oxide overlayers directly on conventional hybrid perovskite halide absorbers without damage. Utilizing water-free ALD Al₂O₃ passivation, a minimum of ten-fold increase in stability against relative humidity (RH) 85% was achieved along with a dramatically improved thermal resistance (up to 250 °C). Moreover, we extend this approach to synthesize nh-TiO₂ directly on hybrid perovskites to establish its potential in inverted photovoltaic devices as a dual stabilizing and electron accepting layer, as evidenced by photoluminescence (PL) quenching.