Paper
12 October 2012 Nanowire tandem solar cells
Renze Wang, Zhiping Zhou
Author Affiliations +
Abstract
Amorphous silicon (a-Si) is a promising material to serve as the top absorbing layers in tandem solar cells. However, due to its intrinsic high defect density, the thicknesses of a-Si layers are limited to a few hundred nanometers. This severely restricts the top cell current density, and therefore the total current density. In this research, we propose a novel structure that utilizing a-Si and crystalline silicon (c-Si) nanowire arrays to serve as top and bottom cells in a tandem solar cell. Two configurations of nanowire tandem solar cells (NWTCs) - a-Si nanowires (NWs) are aligned with c-Si ones (NWTC B) and are horizontally shifted relative to c-Si ones (NWTC A) - are respectively investigated. Numerical analyses present that NWTC A leads to a remarkable photocurrent enhancement of 15.7% and 21.3% when respectively compared with the reference cell (planar tandem cell with c-Si top cell and a-Si bottom cell) with and without optimal IRL, while the performance of NWTC B is similar to that of the reference cell with optimal IRL. Additionally, the usage of c-Si in NWTC A is reduced by 44% compared with the reference cell with IRL. The priorities of NWTC A are mainly attributed to the dielectric (air) attached to the back side of its top cell, causing light to reflect back. In contrast, the back side of NWTC B is mainly attached to c-Si, causing little reflection. The compatibility of intermediate reflecting layers (IRLs) and our proposed structure is studied.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Renze Wang and Zhiping Zhou "Nanowire tandem solar cells", Proc. SPIE 8471, Next Generation (Nano) Photonic and Cell Technologies for Solar Energy Conversion III, 84710T (12 October 2012); https://doi.org/10.1117/12.929104
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KEYWORDS
Amorphous silicon

Nanowires

Tandem solar cells

Solar cells

Absorbance

Absorption

Refractive index

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