Influence of Distributed Bragg Reflectors for Enhanced Light Trapping in Amorphous Silicon Thin-film Solar Cells Using RCWA Method

This study presents a comprehensive analysis of reflectance properties by varying the number of distributed Bragg reflectors (DBRs) in amorphous silicon thin-film solar cells using the Rigorous Coupled Wave Analysis (RCWA) method. This amorphous silicon is emerging as a promising thin-film technology for harvesting solar energy due to its natural abundance and flexibility. The optimized reflectance was observed when varying the number of DBR layers from 1 to 10, enabling the improved and promising light-harvesting schemes in amorphous silicon thin-film solar cells. The optimized 5DBR configuration integrated as back reflector in amorphous silicon thin-film solar cells which is substantially enhances the light-trapping mechanism. The property of photonic crystals depends on various parameters, such as the refractive index, thickness, center wavelength (λc), and material selection. Here, focusing the optimized reflectivity of the 1D photonic crystal structure (Si/SiO2) determined by the center (incident) wavelength, such as 400 nm, with the highest reflectance (~100%) achieved using 5 DBR layers/stacks. In addition, the optimized 5DBR configuration was integrated as a backside reflector in amorphous silicon thin-film solar cells. The structure includes an anti-reflection coating (ARC) of Indium Tin Oxide (ITO), a top grating (ITO), and an absorber layer. The proposed thin-film solar cell achieved a maximum conversion efficiency of 18.0% (Jsc = 27.49 mA/cm2) and 17.65% (Jsc = 26.83 mA/cm2) under transverse electric and transverse magnetic field polarizations, respectively. The thickness of the amorphous silicon absorber region is only 40 nm.