CsPbI3 Based All-Inorganic Perovskite Solar Cells: Further Performance Enhancement of the Electron Transport Layer-Free Structure from Device Simulation

Cesium lead iodide (CsPbI3) has attracted a great deal of attention as an absorption layer material for perovskite solar cells (PSCs) with high stability and suitable band gap (1.72 eV). In response to the problems of defect-induced nonradiative compounding and voltage loss caused by the common perovskite layer, the common strategies of interfacial engineering, altering crystal equivalence, and other modifications involve more complex processes and higher fabrication costs. In order to simplify the process and save costs, this work has omitted the electron transport layer (ETL), while still maintaining a high power conversion efficiency (PCE). This work has simulated PSCs with CsPbI3 (electron transport layer free) and have matched Cu2O as the most suitable hole transport layer (HTL) material. By simulating and optimizing the thickness and defect density of perovskite absorption layer and the defect density of interface defect layer (IDL1, IDL2), and determining the most suitable operating temperature, the PCE of the device can reach 18.8%, which is consistent with the experimental data. The asymmetric effect of the interface defect layer obtained in this work is similar to previous research reports. This research provides an economical solution for high-performance inorganic perovskite solar cells.