TCO and light trapping in silicon thin film solar cells
TCO and light trapping in silicon thin film solar cells
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DOI：
10.1016/j.solener.2004.03.015
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发表时间：
2004-01-01
期刊：
影响因子：
6.7
通讯作者：
Vanecek, M
中科院分区：
文献类型：
--
作者：
Müller, J;Rech, B;Vanecek, M
对于采用非晶硅（a-Si：H）或微晶硅（pc-Si：H）作为吸收材料的薄膜硅太阳能电池和组件，光捕获（即增加入射光的路径长度）对器件性能起决定性作用。本文讨论了如何实现有效的光捕获方案，通过使用纹理透明导电氧化物（TCO）作为光散射，高导电性和透明的前接触硅p-i-n（覆盖层）太阳能电池。重点是应用铝掺杂的氧化锌（ZnO：Al）薄膜，这是通过磁控溅射制备，随后通过湿化学蚀刻步骤纹理的概念。在实验制备的a-Si：H和pc-Si：H太阳电池中，研究了ZnO：Al前接触的电学、光学和光散射特性的影响以及背反射器的作用。此外，提出了一个模型，它允许分析在太阳能电池结构的各个层的光损耗。该模型被应用于开发一个路线图，实现稳定的电池效率高达15%的非晶/微晶叠层电池。为了实现这一点，必要的先决条件是在a-Si：H顶部电池和muc-Si：H底部电池之间引入有效的中间反射器，使用具有非常低的吸光度和理想的光散射特性的前TCO以及低损耗高反射背接触。最后，中频反应溅射技术是一个有前途的和潜在的成本效益的方式，以扩大规模的ZnO前接触制备工业规模的衬底面积。(C)2004爱思唯尔有限公司保留所有权利。
For thin film silicon solar cells and modules incorporating amorphous (a-Si:H) or microcrystalline (pc-Si:H) silicon as absober materials, light trapping, i.e. increasing the path length of incoming light, plays a decisive role for device performance. This paper discusses ways to realize efficient light trapping schemes by using textured transparent conductive oxides (TCOs) as light scattering, highly conductive and transparent front contact in silicon p-i-n (superstrate) solar cells. Focus is on the concept of applying aluminum-doped zinc oxide (ZnO:Al) films, which are prepared by magnetron sputtering and subsequently textured by a wet-chemical etching step. The influence of electrical, optical and light scattering properties of the ZnO:Al front contact and the role of the back reflector are studied in experimentally prepared a-Si:H and pc-Si:H solar cells. Furthermore, a model is presented which allows to analyze optical losses in the individual layers of a solar cell structure. The model is applied to develop a roadmap for achieving a stable cell efficiency up to 15% in an amorphous/microcrystalline tandem cell. To realize this, necessary prerequisites are the incorporation of an efficient intermediate reflector between a-Si:H top and muc-Si:H bottom cell, the use of a front TCO with very low absorbance and ideal light scattering properties and a low-loss highly reflective back contact. Finally, the mid-frequency reactive sputtering technique is presented as a promising and potentially cost-effective way to up-scale the ZnO front contact preparation to industrial size substrate areas. (C) 2004 Elsevier Ltd. All rights reserved.