Cesium-doped zinc oxide as electron selective contact in inverted organic photovoltaics

Abstract

Water based sol-gel processed Cesium-doped Zinc oxide (CZO) with low processing annealing temperature is introduced as an efficient electron selective contact in inverted Organic Photovoltaics (OPVs). The corresponding inverted OPVs not only demonstrate similar performance compared to the well-established sol-gel processed ZnO inverted devices but also maintain their functionality when thick layers of CZO, suitable for the up scaling scenario of OPVs have been used. The three orders of magnitude higher conductivity of CZO than ZnO in combination with the high transmittance above 80%, makes this doped oxide a suitable electron selective contact for the low-cost, roll-to-roll printing process of OPVs.