Photon recycling has received increased attention in recent years following its observation in halide perovskites. It has been shown to lower the effective bimolecular recombination rate and thus increase excitation densities within a material. Here we introduce a general framework to quantify photon recycling which can be applied to any material. We apply our model to idealized solar cells and light-emitting diodes based on halide perovskites. By varying controllable parameters which affect photon recycling, namely, thickness, charge trapping rate, nonideal transmission at interfaces, and absorptance, we quantify the effect of each on photon recycling. In both device types, we demonstrate that maximizing absorption and emission processes remains paramount for optimizing devices, even if this is at the expense of photon recycling. Our results provide new insight into quantifying photon recycling in optoelectronic devices and demonstrate that photon recycling cannot always be seen as a beneficial process.ARB acknowledges funding from a Winton Studentship, Oppenheimer Studentship and the Engineering and Physical Sciences Research Council (EPSRC) Doctoral Training Centre in Photovoltaics (CDT-PV). MA acknowledges funding from the Marie Skłodowska-Curie actions (grant agreement No. 841386) under the European Union’s Horizon 2020 research and innovation programme. SDS acknowledges the Royal Society and Tata Group (UF150033). We thank Luis Pazos-Outón for supplying data for MAPbI3 solar cells. This work was supported by EPSRC grant EP/S030638/1
