Quantification of re-absorption and re-emission processes to determine photon recycling efficiency in perovskite single crystals

Authors

Yanjun Fang, University of Nebraska-LincolnFollow
Haotong Wei, University of Nebraska-LincolnFollow
Qingfeng Dong, University of Nebraska-LincolnFollow
Jinsong Huang, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2017

Citation

Nature Communications, 8:14417, DOI: 10.1038/ncomms14417

Comments

This work is licensed under a Creative Commons Attribution 4.0 International License

Abstract

Photon recycling, that is, iterative self-absorption and re-emission by the photoactive layer itself, has been speculated to contribute to the high open-circuit voltage in several types of high efficiency solar cells. For organic–inorganic halide perovskites that have yielded highly efficient photovoltaic devices, however, it remains unclear whether the photon recycling effect is significant enough to improve solar cell efficiency. Here we quantitatively evaluate the re-absorption and re-emission processes to determine photon recycling efficiency in hybrid perovskite with its single crystals by measuring the ratio of the re-emitted photons to the initially excited photons, which is realized by modulating their polarization to differentiate them. The photon recycling efficiencies are revealed to be less than 0.5% in CH₃NH₃PbI₃ and CH₃NH₃PbBr₃ single crystals under excitation intensity close to one sun, highlighting the intrinsically long carrier recombination lifetime instead of the photon-recycling-induced photon propagation as the origin of their long carrier diffusion length.