Novel a-Si:H/μc-Si:H tandem cell with lower optical loss

We propose a novel a-Si:H/mu c-Si:H tandem cell in order to lower optical losses by using the optimum n-SiOx:H layer as multi-functional layers. The pc-Si:H single-junction solar cell with novel structure was fabricated using this n-SiOx layer which serves both as an n-layer and a ZnO back reflective layer. With novel pc-Si:H solar cell structure a relative increase in J(sc) value up to 4.4% has been observed. In the same way, by employing the optimal n-SiOx:H layer into a novel a-Si:H/mu c-Si:H tandem cell with p-a-SiC:H/i-a-Si:H/n-SiOx:H/p-mu c-SiO: H/i-mu c-Si:H/n-SiOx:H/Ag/Al structure the relative improvement in total J(sc), value by 9% was obtained and therefore the initial efficiency as high as 11.9% (V-oc = 1.38 V, J(sc) = 12.24 mA/cm(2), FF = 0.70) was achieved. Moreover, the improved spectral response of both top and bottom cells were also obtained. These results approved that in this novel structure the first layer of two dual-functional n-SiOx:H layers can work as an n-layer of the top cell and at the same time it can also be functioned as an intermediate layer. On the other hand, the second n-SiOx:H layer can work as an n-layer of the bottom cell and a ZnO back reflective layer. As a result, the reduction in optical losses could be obtained. (C) 2012 Elsevier B.V. All rights reserved.