Performance evaluation of free hole-transport layer CsPbI3 perovskite solar cells

Abstract

Stable inorganic cesium lead iodide (CsPbI3)-based perovskite solar cells received intensive research in the last 2 decades. Several experimental and simulation studies have been performed on CsPbI3 solar cells to achieve high efficiency. However, the usage of the hole-transport layer (HTL) has a good impact on the solar cell’s power conversion efficiency (PCE); HTL layer usage increases the cost of the cell. In this work, a SCAPS-1D simulation study is performed on HTL-free CsPbI3 perovskite solar cells to enhance the device performance. The optical refractive index and reflectivity of CsPbI3 are calculated with density functional theory. The solar cell device structure is investigated and optimized by changing parameters like metal back contact work function, absorber thickness, acceptor density, and defect density. It is found that the optimized solar cell device achieved a PCE of 17.2% with Selenium (Se) as a back metal contact. The optimized absorber thickness for the best PCE is 2000 nm, doping density concentration of 1 × 1019 cm−3, and defect density concentration of 2 × 1012 cm−3. A PCE of 24.5% is achieved using these parameters of the CsPbI3 absorber. The simulation study may guide the fabrication of low-cost and highly efficient HTL-free inorganic CsPbI3 solar cells.