关键词: 硅基薄膜太阳电池/
二维光子晶体/
陷光/
光学吸收提升
English Abstract
Numerical study on conical two-dimensional photonic crystal in silicon thin-film solar cells
Chen Pei-Zhuan1,2,Yu Li-Yuan1,
Niu Ping-Juan1,
Fu Xian-Song1,
Yang Guang-Hua1,
Zhang Jian-Jun2,
Hou Guo-Fu2
1.Engineering Research Center of High Power Solid State Lighting Application System, Ministry of Education, School of Electrical Engineering and Automation, Tianjin Polytechnic University, Tianjin 300387, China;
2.Tianjin Key Laboratory of Photoelectronic Thin-Film Devices and Technique, Key Laboratory of Optical Information Science & Technology, Ministry of Education, Institute of Photoelectronic Thin-Film Devices and Technique, Nankai University, Tianjin 300071, China
Fund Project:Project supported by the Program of Introducing Talents of Discipline to Universities, China (Grant No. B16027), the National Natural Science Foundation of China (Grant Nos. 61176060, 61404074, 61504069, 61377031, 61605145), the Natural Science Foundation of Tianjin, China (Grant No. 14JCQNJC02100), and the Open Fund of the Key Laboratory of Optical Information Science Technology (Nankai University), Ministry of Education, China (Grant No. 2017KFKT015).Received Date:24 July 2017
Accepted Date:03 October 2017
Published Online:20 January 2019
Abstract:To further improve the absorption of thin-film silicon solar cells (TFSSCs), it is essential to understand what kind of texture morphology could present the best light trapping effect, or rather, which structural parameter plays the most important role, and offers the required lateral feature size, height or others. In this paper, the influences of structural parameters of conical two-dimensional photonic crystal (2D PC) on each-layer absorption of the microcrystalline silicon thin film solar cells are numerically studied by using the finite-difference time-domain method when 2D PC is introduced into the intrinsic layer. The results show that both the intrinsic absorption and parasitic absorption are significantly enhanced via introduction of 2D PC into the intrinsic layer. The parasitic absorption is mainly caused by the ITO layer, and the intrinsic absorption shows a sinusoidal fluctuation with the increase of period. It is found that the aspect ratio (height/period) of the 2D PC has a decisive influence on the cell intrinsic absorption. When the period of the 2D PC is less than 1m, the intrinsic absorption first increases and then decreases with the increase of the aspect ratio, and reaches a maximum value with an aspect ratio of 1. For the case of period larger than 1m, the aspect ratio needed to obtain the maximum result is smaller than 1. What is more, the larger the period, the smaller the aspect ratio for maximizing the intrinsic absorption will be. The peak intrinsic absorption can be obtained when a 2D PC with a period of 0.5m and an aspect ratio of 1 is introduced. Compared with that of the flat cell, the short-circuited current density of the above optimized 2D PC cell can be significantly enhanced by 5.8 mA/cm2(from 21.9 to 27.8 mA/cm2), corresponding to a relative enhancement of 27%. In order to improve antireflection performance, it is critical to adopt a textured front-surface morphology where the aspect ratio is higher than 1/2. In addition, the intrinsic absorption increases with the increasing fill factor, and reaches a maximum value when the fill factor of the 2D PC is close to 0.9. The research results of this paper break through the traditional viewpoint of light trapping mechanism which points out that the light trapping effect is mainly dependent on the lateral feature size of the texture, and provide an important guide for obtaining optimized random or periodic texture via experiment.
Keywords: thin-film silicon solar cells/
two-dimensional photonic crystal/
light trapping/
optical absorption enhancement
