A Highly Conductive Titanium Oxynitride Electron‐Selective Contact for Efficient Photovoltaic Devices

Abstract High‐quality carrier‐selective contacts with suitable electronic properties are a prerequisite for photovoltaic devices with high power conversion efficiency (PCE). In this work, an efficient electron‐selective contact, titanium oxynitride (TiO_xN_y), is developed for crystalline silicon (c‐Si) and organic photovoltaic devices. Atomic‐layer‐deposited TiO_xN_y is demonstrated to be highly conductive with a proper work function (4.3 eV) and a wide bandgap (3.4 eV). Thin TiO_xN_y films simultaneously provide a moderate surface passivation and enable a low contact resistivity on c‐Si surfaces. By implementation of an optimal TiO_xN_y‐based contact, a state‐of‐the‐art PCE of 22.3% is achieved for a c‐Si solar cell featuring a full‐area dopant‐free electron‐selective contact. Simultaneously, conductive TiO_xN_y is proven to be an efficient electron‐transport layer for organic photovoltaic (OPV) devices. A remarkably high PCE of 17.02% is achieved for an OPV device with an electron‐transport TiO_xN_y layer, which is superior to conventional ZnO‐based devices with a PCE of 16.10%. Atomic‐layer‐deposited TiO_xN_y ETL on a large area with a high uniformity may help accelerate the commercialization of emerging solar technologies.