Theoretical analysis of performance improvement of thin film solar cells with two-dimensional photonic crystals and distributed Bragg reflector textured structures

A new approach that incorporates two-dimensional photonic crystals (2D-PhCs) and distributed Bragg reflector (DBR) for light trapping to improve the performance of thin film solar cells (TFSCs) was theoretically demonstrated. With careful design optimization, the presented light-trapping structure can lead to a remarkable efficiency enhancement for the cells with very thin silicon active layers due to the significantly enhanced absorption. Rigorous coupled wave analysis (RCWA) simulations reveal that the absorption enhancement could be tuned by tailoring the parameters of the PhC structure. In the longer wavelength range (800 nm-1100 nm), enhanced light absorption can also occur, which is very important for improving absorption in TFSC. The designed back textured structures on the electrode lead to high scattering and diffraction of light when the hybrid structures provide a phase difference of π which helps to increase the effective thickness of TFSC and results in a higher short circuit current. Besides, the potential solar cell quantum efficiency (QE) was estimated.