High-Efficiency Silicon Solar Cells—Materials and Devices Physics

High-efficiency Si solar cells have attracted great attention from researchers, scientists, engineers of photovoltaic (PV) industry for the past few decades. Many researchers, scientists, and engineers in both academia and industry seek solutions to improve the cell efficiency and reduce the cost. This desire has drawn stronger support from major funding agencies and industry and stimulated a growing number of major research and research infrastructure programs, and a rapidly increasing number of publications in this filed. This article reviews materials, devices, and physics of high-efficiency Si solar cells developed over the last 20 years and presents representative examples of superior performances and competitive advantages. In this paper there is a fair number of topics, not only from the material viewpoint, introducing various materials that are required for high-efficiency Si solar cells, such as base materials (FZ-Si, CZ-Si, MCZ-Si, and multi-Si), emitter materials (diffused emitter and deposited emitter), passivation materials (Al-BSF, high-low junction, SiO2, SiOx, SiNx, Al2O3 and a-Si:H), and other functional materials (antireflective layer, transparent conductive oxide and metal electrode), but also from the device and physics point of view, elaborating on physics, cell concept, development, and status of most types of high-efficiency Si solar cells, including passivated emitter and rear contact (PERC), passivated emitter and rear locally diffused (PERL), passivated emitter and rear totally-diffused (PERT), Pluto, PANDA, interdigitated back-contacted (IBC), emitter-wrap-through (EWT), metallization-wrap-through (MWT), heterojunction with intrinsic thin-layer (HIT), and so on. Finally, the technical data of these high-efficiency Si solar cells has been tabulated.