Design of High Absorption Structure Using ITO/TiO2 Photonic Crystal Substrate for a-Si Thin Film Solar Cells

• Main Authors: Shih, Huai-Shiang, 施懷翔
• Other Authors: Kuo, Hao-Chung
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/94423322313857517553

碩士 === 國立交通大學 === 照明與能源光電研究所 === 100 === We demonstrate a flatted photonic crystal (PhC) structure to serve both function of reflection and light trapping effect in a-Si thin film solar cells. In this work, we build a model in simulation of PhC structures in different side of solar cells, rear and front, which is calculated by rigorous coupled-wave analysis (RCWA) method. In rear side of cell, we chose materials of ITO (n=2.01) and a-Si (n=4.25) to for construction of hexagonal hole and rod array. The optimum structure enhance absorption at about 3.26% by hole and about 2.89% by rod. In other hand, optimized PhC structures can reduce thickness of active layer at about 35% by enhance optical path length in long wavelength region. In front side, we replace a-Si by TiO2 (n=2.49) to avoid energy loss brought by a-Si in PhC structures. The optimized ITO/TiO2 PhC structure enhance at about 18.93% by hole and at about 16.97% by rod. The ITO/TiO2 PhC structures at front side provide anti-reflective effect in short wavelength region and light scattering effect in long wavelength region. Finally, we simulated optical properties of two substrates possess the same dimension of the front PhC structures. The reflectance and transmittance spectrum show that the PhC substrates contribute more absorption in active layer at large angles of incident light.