Park Jinjoo, Dao Vinh Ai, Kim Sangho, Pham Duy Phong, Kim Sunbo, Le Anh Huy Tuan, Kang Junyoung, Yi Junsin
College of Information and Communication Engineering, Sungkyunkwan University (SKKU), Suwon, Kyunggi, 440-746, Korea.
Institute of Fundamental and Applied Sciences, Duy Tan University, Ho Chi Minh City, 700000, Vietnam.
Sci Rep. 2018 Oct 18;8(1):15386. doi: 10.1038/s41598-018-33734-y.
We investigated high-efficiency two-terminal tandem photovoltaic (PV) devices consisting of a p/i/n thin film silicon top sub-cell (p/i/n-TFS) and a heterojunction with an intrinsic thin-layer (HIT) bottom sub-cell. We used computer simulations and experimentation. The short-circuit current density (J) of the top sub-cell limits the J of the p/i/n-TFS/HIT tandem PV device. In order to improve the J of the top sub-cell, we used a buffer-layer at the p/i and i/n interface and a graded forward-profile (f-p) band gap hydrogenated amorphous silicon germanium active layer, namely i-layer, in the top sub-cell. These two approaches showed a remarkable raise of the top sub-cell's J, leading to the increase of the J of the PV tandem device. Furthermore, in order to minimize the optical loss, we employed a double-layer anti-reflective coating (DL-ARC) with a magnesium fluoride/indium tin oxide double layer on the front surface. The reduction in broadband reflection on the front surface (with the DL-ARC) and the enhanced optical absorption in the long wavelength region (with the graded f-p band gap) resulted in the high J, which helped achieve the efficiency up to 16.04% for inorganic-inorganic c-Si-based tandem PV devices.
我们研究了由p/i/n薄膜硅顶子电池（p/i/n-TFS）和本征薄层异质结（HIT）底子电池组成的高效双端串联光伏（PV）器件。我们采用了计算机模拟和实验方法。顶子电池的短路电流密度（J）限制了p/i/n-TFS/HIT串联光伏器件的J。为了提高顶子电池的J，我们在顶子电池的p/i和i/n界面处使用了缓冲层，并采用了渐变正向分布（f-p）带隙氢化非晶硅锗有源层，即i层。这两种方法使顶子电池的J显著提高，从而导致光伏串联器件的J增加。此外，为了将光学损耗降至最低，我们在正面采用了由氟化镁/氧化铟锡双层组成的双层抗反射涂层（DL-ARC）。正面宽带反射的降低（采用DL-ARC）以及长波长区域光学吸收的增强（采用渐变f-p带隙）导致了高J，这有助于无机-无机c-Si基串联光伏器件实现高达16.04%的效率。
