Hole-transport materials with greatly-differing redox potentials give efficient TiO2–[CH3NH3][PbX3] perovskite solar cells

Two diacetylide-triphenylamine hole-transport materials (HTM) with varying redox potential have been applied in planar junction TiO2-[CH3NH3] PbI3-xClx solar cells leading to high power-conversion efficiencies up to 8.8%. More positive oxidation potential of the HTM gives higher V-OC and lower J(SC) illustrating the role of matching energy levels, however both HTMs gave efficient cells despite a difference of 0.44 V in their redox potentials.