Simulation of steady-state characteristics of heterojunction perovskite solar cells in wxAMPS

Methylammonium lead iodide perovskite solar cells in a p-i-n configuration were modeled and simulated under steady-state conditions using wxAMPS software. The J-V characteristics and the power conversion efficiency of modeled devices were predicted under various operating conditions. The parameters adopted in the model were derived from the properties of the reported materials in the literature, and the simulated J-V curves were compared with experimental data. Detailed analyses were performed on the energy band diagrams, the distribution of the electric field, the profile of charge densities, and the rate of generation and recombinations under standard testing conditions and realistic operating conditions. The dark current was fitted to an ideality factor of 1.4, indicating that the recombination was via the SRH and band-to-band mechanisms. The optical generation process exhibited an exponential decay with an initial value of 1.5×10¹⁶ cm^-3s^-1, and the same magnitude of recombination was observed under open-circuit conditions. The roles of the anode and the cathode work functions (Φ_ITO, Φ_m) were examined. It was found when the Φ_ITO is greater than 5.2 eV together with Φ_m below 4.4 eV, an optimal PCE of 24 % can be obtained. Further, the device response under concentrated light was simulated in two steps with and without the presence of the alleviated temperatures. The results showed the PSCs have the potential to be used for concentrated photovoltaics if a cooling mechanism is provided or the cell is operated in a low-temperature ambient.