Utilizing sub-wavelength grating to increace light-trapping in solar cells

Two kinds of sub-wavelength grating structures which can significantly enhance the light trapping of solar cells are proposed, which are hemispheres and cylindrical gratings, respectively. Based on the diffraction characteristics of sub-wavelength grating, the strict coupling wave analysis method is used to simulate and calculate the diffraction efficiency of two sub-wavelength gratings. The Matlab calculation shows that for the optimized hemispheres sub-wavelength grating, the wavelength is in the range of 300-1000 nm, the average transmission efficiency is 87.6% for the incident angle range of 0°-75°, and has good redundancy; and for the optimized cylindrical sub-wavelength grating, the wavelength is in the range of 400-1000 nm, the average transmission efficiency is 88% for the incident angle range of 0°-80°. Both structures meet the harsh requirement of solar cells for wide-spectrum, wide-angle light trapping. © 2018, Editorial Board of Acta Energiae Solaris Sinica. All right reserved.