Numerical modeling and performance optimization of carbon-based hole transport layer free perovskite solar cells

Owing to low production cost and ease of processing, hole-transport layer (HTL) free carbon electrode-based perovskite solar cells (c-PSCs) have emerged as a potential photovoltaic (PV) technology. Despite this, c-PCSs still have to achieve the high photon conversion efficiency exhibited by standard PSCs using HTLs. In the present work, device modeling of Csx(FA0.4MA0.6)1-xPbI2.8Br0.2 based HTL-free c-PSC was presented using the simulation program Solar Cell Capacitance Simulator (SCAPS). Output results were successfully replicated in the simulation that were comparable to experimentally reported values. Furthermore, several parameters affecting device performance, such as the absorber layer, the electron transport layer (ETL), front contact thicknesses, and doping concentrations, are studied and optimized. Additionally, the defect density at the perovskite/ETL interface is investigated. Under optimized conditions, a high open-circuit voltage of 1.13 V, short-circuit current density of 22.54 mA/cm2, fill factor of 79.75%, and photon conversion efficiency of 20.43% is achieved. Results demonstrate the promising features of the proposed HTL-free c-PSC. Lastly, the impact of temperature and work function of back metal contacts were also examined. The simulation results suggest a direction to design low-cost and highly efficient HTL-free c-PSCs.