Impact of Radiative Cooling on Multi-Junction Solar Cells Under Unconcentrated and Low-Concentrated Light

Multi-junction solar cells are a key technology for high efficiency photovoltaics. Since their performance and reliability are strongly influenced by the operating temperature, their effective thermal management is an important concern, especially in concentrating photovoltaics. Radiative cooling is a cost-effective, passive, and scalable solution for thermal management of solar cells. This technique can effectively expel a large amount of heat by radiating it into outer space through the atmospheric transparency window between 8 and 13 μm, In this work, we analyze the impact of this cooling strategy on multi-junction solar cells under different illumination conditions by means of a detailed balance model for the cell/cooler system. We show that the increase in efficiency resulting from reduced operating temperature is more significant for multi-junction architectures in comparison to single-junction ones, because of their more negative temperature coefficient. Furthermore, we explore two viable approaches for successfully utilizing the radiative cooler in low-concentration photovoltaic systems. The first method involves increasing the size of the radiative cooler area, while the second entails combining it with a nonradiative cooling system.