Probing the photophysics of lead-halide hybrid perovskite junctions under very intense optical irradiance

Hybrid lead halide perovskites are most highly-performing absorber materials for advanced thin film solar cells, with certified record values of Power Conversion Efficiency higher than 25% [1]. They are also extremely appealing for high concentrated photovoltaic applications at high levels of optical irradiance [2,3] and as light emitting devices [4]. Actually, the photophysics of photovoltaic perovskite junctions under high irradiance is quite complex, due to soft and defective crystalline structure, leading to material instabilities. Therefore, to assess the impact of intense illumination on the performances and long-term reliability of hybrid perovskites is of major importance and still an open research challenge. Dynamical characterizations of surface photovoltage (SPV) and photoluminescence (PL) may help to unveil the photophysics of the system. We apply novel laser-assisted Time-Resolved Scanning Electron Microscopy (TR-SEM) [5] as a fast way to visualize dynamical SPV and we couple it to in-situ quasi-steady state PL to study long-term evolution of charge dynamics in MAPbI3 films, excited by intense optical irradiance at 500 suns, in dependence on the kind of selective contacts. 1. M. A. Green, et al. Prog. Photovoltaics Res. Appl., 28, 3 (2020). 2. Wang, Z., et al., Nat. Energy, 3, 855-861 (2018). 3. Lin, Q., et al., Adv. Sci., 5, 1–8 (2018). 4. Kim, Y.-H., Cho, H.,Lee, T.-W., Proc. Natl. Acad. Sci., 113, 11694–11702 (2016). 5. Irde, G. et al., Micron 121, 53–65 (2019).