The fundamental tradeoff between light absorption and carrier collection ranks as one of the most important factors for the low cost and high efficiency photovoltaic devices. As solar cells become thinner, absorption losses become more important because a thinner active layer absorbs much less light. Fortunately, light management has emerged as a powerful approach for overcoming this tradeoff, because which permits the manipulation of incident optical fields, and could control of the light propagation and energy distribution in photovoltaic devices, ultimately achieves absorption enhancements while without sacrificing the electrical performance in the active layer. From three perspectives including ray optics, traditional wave optics and nanophotonics, the basic physical concepts of light confinement and enhancement in typical light trapping structures are introduced in detail, and the trend of light management is also presented in this paper.
