Proceedings of Perovskite Thin Film Photovoltaics (ABXPV17)
Publication date: 18th December 2016
Perovskite solar cells with all-organic transport layers have shown efficiencies rivalling their counterparts that employ inorganic transport layers while avoiding high temperature processing. In this contribution we show that reduced non-radiative recombination as a result of better blocking behaviour at the interface between the perovskite and fullerenes is the determining factor for high open-circuit voltages in our (p-i-n) perovskite solar cells. Exemplary, we employ UPS/IPES to determine the energetics of the contact layers adjacent to the perovskite and correlate this with the fluorescence lifetime, which allows us to enhance the open-circuit voltage while preserving good charge colletion efficiency in our devices (i.e. high fill-factors above 70%). Consequently we produce solar cells with efficiencies up to 19.4% accompanied by open-circuit voltages as high as 1.16V reflected in external radiative efficiencies of up to 0.3% at carrier densities equivalent to solar AM1.5G conditions. This work highlights the importance of well-chosen selective contacts in achieving highly efficient devices, adresses the losses in perovsktie solar cells and seeks to redress some of the misleadings regarding figures-of-merit often presented (e.g. photoluminescence quenching).