Simulation approach for optimization of device structure and thickness of HIT solar cells to achieve ∼27% efficiency

► Simulation study of silicon HJ and HIT solar cell by AFORS-HET software. ► Optimization of layers thickness and cell structure for producing high efficiency. ► Obtained record ∼27% efficiency in bifacial HIT solar cell. Optimization of thicknesses of n-type a-Si:H emitter layer, front a-Si:H i-layer and p-type c-Si base wafer as well as optimum heterojunction (HJ) and HJ with intrinsic layer (HIT) solar cells are performed using AFORS-HET simulation software. By optimization, we realized record efficiency of 27.02% in bifacial HIT solar cell at emitter layer, front i-layer and c-Si base wafer thicknesses of 6nm, 3nm and 200μm, respectively. Interestingly when the thickness of c-Si wafer was reduced to 58μm, while keeping the thicknesses of emitter and front i-layers as same as 6nm and 3nm, respectively, efficiency in bifacial cell got reduced to 26.45%. All cell structures generated highest efficiency at emitter layer and front i-layer thicknesses of 6nm and 3nm, respectively. However, optimum c-Si base wafer thickness was varied according to the following cell structures: simple HJ and HIT cells showed highest efficiency at 300μm, HJ with BSF layer cell at 98μm, HIT with BSF layer at 58μm. It is worth mention that, efficiency in bifacial cell at 58, 98 and 200μm was varied nominally. These optimizations may help in producing low cost high efficiency HJ and HIT solar cells technology.