Neutral-Colored Transparent Crystalline Silicon Solar Cells

Abstract

Transparent solar cells, which combine visible transparency and solar energy conversion, are being developed for applications in which conventional opaque solar cells are unlikely to be feasible, such as windows of buildings or vehicles. However, transparent solar cells developed to date have limitations in efficiency and stability. Crystalline silicon (c-Si) is one of the best candidates to develop transparent solar cells with high efficiency and stability, because conventional c-Si solar cells are known to exhibit high efficiency and long-term stability compared with other solar cells. However, the opaque characteristic of the c-Si wafer hinders the development of transparent solar cells using c-Si. In this presentation, we introduce a novel approach to develop neutral-colored transparent c-Si solar cells that exhibit the highest efficiency among neutral-colored transparent solar cells developed to date. Also, we review recent progress in transparent solar cells along with strategies that enable the transparency of conventional solar cells, including thin film technology, selective light transmission technology, and luminescent solar concentrator technology. From fundamental research to commercialization of the transparent solar cells, three main perspectives should be considered: (1) high power conversion efficiency at the same average visible transmittance; (2) aesthetic factors, which should not detract from applications such as buildings and vehicles; and (3) feasibility for real-world applications, including modularization and stability evaluation. We present the distinct analysis criteria for these main perspectives and discuss their importance.