Light trapping mechanism of hemisphere cone arrays for silicon solar cells

Abstract Hemisphere cone arrays (HCAs) is a popular light trapping structure in silicon solar cells. However, the light trapping mechanism research of that in solar cells is lacking. In this paper, the light trapping mechanism of the HCAs in silicon solar cells is studied by combination of numerical analysis and geometrical optics simulation. The results show that the HCAs structure can reduce surface reflectance by ∼60% compared with flat structure by multiple injections of the incident light. At the same time, the HCAs can make ∼43% unabsorbed light return to the absorbing layer of solar cells again. To verify the theoretical calculation results, a flat and a square hemispherical cone arrays PDMS thin films are prepared by a micro/nano-processing method, and the reflectivities of a silicon wafer covered the flat and the HCAs PDMS thin films were measured. The experimental measured results are basically consistent with the theoretical calculation results. The numerical calculation results also show that the total optical path length of the thin film Si solar cell covered with the HCAs structure increases from 2 ω to 4 ω .