Ultra high solar concentration for high efficiency solar cells

The development of Photovoltaic (PV) systems operating under very high solar concentration has attracted considerable interest and motivated a significant amount of research and development over the past two decades, driven by the prospect of achieving exceptionally high solar-to-electricity conversion efficiency, and, ultimately, lowering the cost of solar electricity. Although this field has experienced a decline in recent years, mainly due to the rapid expansion of conventional PV, conversion under ultra-high solar flux (≥1000 suns) remains a subject of singular interest that stems from the interplay of diverse physical, optical, and thermal phenomena, the significant technical challenges inherent to its practical implementation, and its direct relevance to several high-efficiency PV cell technologies currently under development. In this article, we review the physical motivations and principles underlying the operation of PV cells under ultra-high solar concentration. We describe the limiting mechanisms that can significantly affect the performance of PV cells under such extreme conditions, before listing and analysing the strategies proposed to limit their effects. Finally, we review and discuss the emerging high-efficiency PV cell technologies and provide practical recommendations grounded in two decades of ultra-high concentration PV research.