Self-Heating of Planar Perovskite Solar Cells Depending on Active Material Properties

The effect of perovskite material properties on the power conversion to electricity and, especially, to heat and the operation temperature of perovskite solar cells (PSCs) was simulated. The operation temperature is topical because the technology is progressing toward commercialization: first, because cells are subject to varying outdoor conditions, and second, because commercial use benefits from accurate power production prediction, in which the cell temperature is an influential factor. This article products insights into how perovskite absorber properties, including the band gap (E_g), diffusion length, and layer thickness, affect the heat production and temperature coefficient of planar PSCs based on optoelectronic simulations. The change in heat production with an increasing band gap was observed to be quasi-linear: self-heating decreased by approximately −0.38 W/(m² meV) until E_g = 1.7 eV, after which the slope slightly relaxed. Over the studied band gap range of 1.2–2.2 eV, the change in heat production as a function of the band gap resulted in the self-heating of a small band gap (E_g = 1.2 eV) device, 575 W/m², to be more than twice that of a large band gap (E_g = 2.2 eV) device, 253 W/m². Further, the steady-state operating temperature at the maximum power point was modeled and shown to significantly vary between 30 °C for a large (2.2 eV) band gap device and 44 °C for a small (1.2 eV) band gap device in the example outdoor conditions of 1000 W/m² irradiance, 20 °C ambient temperature, and ca. 1 m/s wind speed. The self-heating-induced temperature increment subsequently affected the power production predictions of different band gap devices, from −6 to −1%. The results presented here can improve the operation temperature and power production predictions of PSCs with alternative perovskite absorbers.