The influence of the conduction band engineering on the perovskite solar cell performance

Abstract

The present work investigated numerically, using SCAPS software, the impact of conduction band alignment between the absorber and electron transport layer (ETL) on the perovskite solar cell performance. The conduction band alignment was tailored by inserting an interfacial thin layer between the absorber and ETL. The architecture of the proposed structure consists of CdS as an electron transport layer, MAPbI3 as an absorber layer, and the spiroOMeTAD as a hole transport layer (HTL). Before inserting the interfacial layer, an adjustment of the doping density of ETL and HTL and the thickness of the perovskite solar layers have been optimized to obtain the best PSC performance. It was found that the best power conversion efficiency of 18 % was obtained at a doping density of 1022 cm−3 for ETL and 1019 cm−3 for HTL and thickness of 250 nm, 400 nm, and 200 nm for ETL, absorber, and HTL respectively. Individual interfacial layers, with different electron affinities, are sandwiched between the CdS/Perovskite layers to achieve different conduction band alignments. Based on the electron affinity of inserted layer, different structures from spike and cliff in the conduction band alignment were achieved. The results reveal that the inserted interfacial layer improved the solar cell performance when the inserted layer produce a spike-cliff conduction band offset at the absorber-interfacial layer interface and interfacial layer-ETL interface respectively.