Efficiency Loss And Hysteresis Analyses For Perovskite Solar Cells By An Equivalent Circuit Model

With the rapid development of theoretical research and technological progress of perovskite solar cells(PVSCs),characterizing and quantifying loss mechanisms and abnormal hysteresis intuitively and reliably become an important scientific problem that needs to be solved urgently for stable and high-performance photovoltaic devices.Based on the comprehensive considerations of optical loss,series-resistance loss,shunt resistance loss,non-radiative bulk recombination,non-radiative surface recombination and hysteresis effect,the traditional detailed balance theory is revised,and a novel equivalent circuit model is introduced.Moreover,by comparing with the drift-diffusion model and experimental results,the validity,practicability,and accuracy of the equivalent circuit model are verified.Here the main research works and corresponding results are briefly introduced as follows:Firstly,characterizing bulk and surface recombination,an improved equivalent circuit model is proposed.Based on the improved model,the influences of optical structure,ohmic resistance,and non-radiative recombination on the performances of PVSCs are systematically analyzed.Additionally,through quantifying all above loss mechanisms,the working principles of PVSCs are understood.Secondly,on the basis of the improved circuit model,by decoupling the steadystate current describing pure carrier transport with the capacitance current describing hysteresis,a hysteresis equivalent circuit model with reduced complexity is introduced.Thirdly,based on the consistency of the equivalent circuit model and driftdiffusion model,the typical expressions of the nonlinear capacitances describing the hysteresis are summarized,and thus the hysteresis effect is quantified.Meanwhile,a simple approach for judging the non-radiative combination type is offered.Finally,the improved equivalent circuit model describing the current-voltage characteristics and the hysteresis equivalent circuit model describing the hysteresis effect are compared to experimental results and analyses,which proves the reliability and accuracy of analyzing the loss mechanisms,and the usefulness of hysteresis quantification.In summary,the equivalent circuit model proposed is a comprehensive and effective simulation tool for PVSCs.