High-performance inverted planar perovskite solar cells based on solution-processed rubidium-doped nickel oxide hole-transporting layer

Abstract

Abstract Organic–inorganic hybrid perovskite solar cells (PVSCs) have attracted great attention due to the high power conversion efficiency (PCE). For the p-i-n inverted structure PVSCs, the hole transporting layer (HTL) plays an important role in achieving high efficient and stable PVSCs by improving charge extraction, reducing interfacial recombination, and modifying band alignment etc. In this work, rubidium (Rb) doped NiOx (Rb:NiOx) was employed as HTL to study the impacts on the optoelectronic properties and the photovoltaic performance. Both NiOx and Rb:NiOx films were smooth and highly transparent with a simple solution-based method. The Rb:NiOx films exhibited better conductivity and effectively elevated the valence band maximum (VBM). At the same time, the Rb doping induced a better morphology of perovskite film with larger crystals size on top. Therefore, Rb doping resulted in significantly improved hole extraction and reduced recombination losses. As a result, the photovoltaic performance of the PVSCs was remarkably increased from 14.48% to 17.21%.