Copper Oxide Buffer Layers by Pulsed-Chemical Vapor Deposition for Semitransparent Perovskite Solar Cells

Abstract

In semitransparent perovskite solar cells with n-i-p configuration, thermal evaporation is the common method to deposit the sputter buffer material, such as molybdenum oxide and tungsten oxide. Buffer layers are especially necessary when using organic hole transporting layers, as they are more susceptible to get damaged when sputtering the top transparent conducting oxide. However, there is a limited selection of possible materials and limited control of the materials properties by thermal evaporation, which leads to inefficient protection against sputtering and poor air stability. While there have been well-established buffer layers by atomic layer deposition, including tin oxide, for p-i-n structured semitransparent perovskite solar cells, this is not the case for n-i-p structured devices. Here, copper oxide is demonstrated by pulsed-chemical vapor deposition incorporated into perovskite solar cells for the sputter buffer layer, which result in stable encapsulated semitransparent devices maintaining over 95% of the maximum efficiency under AM 1.5 G at maximum power point tracking for 150 h without any temperature control.