A comprehensive simulation study of methylammonium-free perovskite solar cells

Abstract

The power conversion efficiency (PCE) of thin-film solar cells (TFSCs) has drastically increased in the last few years. In this regard, perovskite solar cells (PSCs) come on the top thanks to their bandgap tunability, lower fabrication cost, and high absorption coefficient. In this work, a comprehensive simulation study is presented in which methylammonium-free PSCs are analyzed and designed. Also, the design of the presented solar cell structure is based on using a hole transport layer (HTL)-free. So, the design is carried out in such a way as to prevent the instability and cost issues associated with the organic materials, usually incorporated in HTLs, as well as methylammonium (MA) which limits the device operation stability. Next, the conduction band offset between the perovskite as an absorber and the electron transport layer (ETL) is controlled to provide a spike-like band offset that is more desirable by selecting appropriate materials serving as ETLs. The work function of the back contact is also investigated, and it is found that using Carbon, which has a lower cost than gold, is beneficial to get high efficiency. An enhanced performance has been achieved by combining the different steps of the design. This is reflected in the PCE which performs 25.35% instead of the initial calibrated cell which shows a PCE of 20.7%. The PCE could further be boosted to 27.8% if reduced absorber and interface defects are included. The calibration and simulation of the presented PSCs were done by utilizing SCAPS one-dimensional simulator, based on practical material parameters, at AM1.5 illumination.