Practical efficiency limit of laser power converters based on lead halide perovskite

An ideal laser power converter (LPC) has a power conversion efficiency (PCE) limit of 100%; however, in a real device, additional losses degrade the PCE limit appreciably. We developed an approach to estimate the PCE of perovskite LPCs based on the state-of-the-art perovskite solar cells with a variety of losses. The practical PCE limit is found to be 60.2% under a 785 nm laser with power density of 50 mW/cm2, which result is corroborated by our experimentally measured PCE of 58.6%. Despite a comparable PCE to that of GaAs LPCs, the power output of current perovskite LPC is much lower due to the series resistance, which may be low enough for solar cells but needs to be reduced by one order of magnitude for LPCs. Moreover, the PCE can be further improved by confining emission angle and resorting to wider bandgap perovskite. Finally, a power output over 7 W/cm2 with PCE over 80% is estimated to be within reach for perovskite LPCs.