Design of double-layer SiNx:H film and its application in c-Si PERC solar cells

The existing solar cell anti-reflection film technology still cannot adequately meet the light trapping needs of solar cells. In this Letter, double-layered SiNx:H films were prepared for c-Si solar cells by plasma enhanced chemical vapor deposition (PECVD). Herein, the authors introduce a simple, convenient method to lower the reflectance in silicon solar cells by applying double-layered SiNx:H film to increase the refractive index of such film. Compared to the single layer film devices, the reflectance of the double-layered SiNx:H film can be significantly reduced by >30% through enhanced absorption of light in solar cells. This method has achieved an average of 0.08% conversion efficiency, with the highest being 0.18%. In addition, the double-layer film solar cells also showed a better passivation performance than that of the single-layer film, so that the minority carrier lifetime was up to 137 mu s. Therefore, the improvement of solar cell efficiency mainly come from the decrease of reflectivity and the improvement in film passivation performance. The work of this Letter demonstrated the light trapping advantages and passivation enhancement performance of double-layer films applied to single crystal silicon solar cells.