A new thin-film solar cell structure with a broadband absorption enhancement is proposed. The active a-Si:H film is sandwiched by two periodic pyramidal structured layers. The upper dielectric pyramidal layer acts as matching impedance by gradual change of the effective refractive index to enhance the absorption of the active layer in the short wavelength range. The lower metallic pyramidal layer traps light by the excitation of Fabry-Perot (FP) resonance, waveguide (WG) resonance and surface plasmon (SP) mode to enhance the absorption in the long wavelength range. With the cooperation of the two functional layers, a broadband absorption enhancement is realized. The structure parameters are designed by the cavity resonance theory, which shows that the results are accordant with the finite-difference time-domain (FDTD) simulation. By optimizing, the absorption of the sandwich structure is enhanced up to 48% under AM1.5G illumination in the 350-900 nm wavelength range compared to that of bare thin-film solar cells. (C) 2012 Optical Society of America
1.Sichuan Univ, Dept Phys, Chengdu 610064, Peoples R China 2.Chinese Acad Sci, Inst Opt & Elect, Chengdu 610209, Peoples R China 3.Chinese Acad Sci, Chongqing Inst Green & Intelligent Technol, Chongqing 401122, Peoples R China
Li, Chuanhao,Xia, Liangping,Gao, Hongtao,et al. Broadband absorption enhancement in a-Si:H thin-film solar cells sandwiched by pyramidal nanostructured arrays[J]. OPTICS EXPRESS,2012,20(19):A589-A596.