The key factors on silicon-based tandem thin film solar cells

The key factor for high efficiency of tandem Si-based thin film solar cells is to optimize the whole configuration for improving its utilization of solar energy besides the active layers of device-quality level. Several aspects reached in our lab are discussed in this paper. A double structure of P + window layer was proposed and studied. An interlayer between top-cell and bottom-cell in the tandem structure for forming a micro-cavity in top-cell was simulated by the software programmed by ourselves. Finally, the results of two types of tandem solar cells, namely, a-Si/a-Si and a-Si/μc-Si with the light trapping back-reflection structure are reported.