Efficiency simulations on perovskite solar cells only using experimentally determined reflectance and transmittance data

The constantly refreshed efficiency records have put the perovskite solar cells (PSCs) at the forefront of photovoltaic research. Power conversion efficiency (PCE) is a key factor as well as the most intuitive parameter to assess the photovoltaic performance of a PSC. This work proposes an easier and faster scheme to simulate PCEs of PSCs only using the reflectance and transmittance data of the perovskite materials. Taking the CH3NH3PbI3 PSC and the Cs2AgBiBr6 PSC as examples, the complex refractive indices of CH3NH3PbI3 and Cs2AgBiBr6 are derived from the experimentally measured reflectance and transmittance spectra, which are then used in the transfer matrix method to simulate the process of light propagating through the PSC. The light absorption derived from the transfer matrix method determines the photo-generated current in the current-voltage characteristics. Influences of the series resistance and the shunt resistance on PCEs are also taken into account. The best-performing CH3NH3PbI3 and Cs2AgBiBr6 PSCs fabricated in this work exhibit PCEs of 15.72% and 1.55%. By comparison, simulations predict PCEs of 18.45% and 4.64%, which are slightly overestimated but reasonable.