Fabrication of CdS/CdTe-Based Thin Film Solar Cells Using an Electrochemical Technique
Fabrication of CdS/CdTe-Based Thin Film Solar Cells Using an Electrochemical Technique
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DOI：
10.3390/coatings4030380
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发表时间：
2014-09-01
期刊：
影响因子：
3.4
通讯作者：
Abbas, A.
中科院分区：
文献类型：
--
作者：
Dharmadasa, I. M.;Bingham, P. A.;Abbas, A.
基于碲化镉 (CdTe) 的薄膜太阳能电池是复杂的器件，具有实现高转换效率的巨大潜力。缺乏对材料问题和器件物理的理解会减缓这些器件的快速进步。本文将文献中的相关结果与基于电镀 CdS 和 CdTe 的研究项目的新结果相结合。使用了广泛的分析技术来研究材料和器件结构。实验发现n型、i型和p型CdTe可以很容易地通过电镀生长。这些材料层由纳米和微米棒型或柱状型晶粒组成，垂直于基底生长。化学计量材料表现出最高的结晶度和电阻率，并且接近这些条件生长的层在热处理时表现出n -> p 或p -> n 转换。 CdCl2处理的总趋势是逐渐将CdTe材料的n型电学性质转变为i型或p型导电。这项工作还确定了 CdTe 层在 385 +/- 5 摄氏度下的快速结构转变，以及在高温下退火或生长时在较高温度下的缓慢结构转变。第二次转变发生在 430 摄氏度之后，需要更多的工作来理解这种逐渐的转变。这项工作还确定了 CdS/CdTe 存在两种不同的太阳能电池配置，这造成了复杂的情况。最后，本文提出了下一代 CdTe 基太阳能电池的发展方向，该电池在梯度带隙结构中利用柱状性质的低成本材料。这些设备可以吸收太阳光谱中的紫外线、可见光和红外线辐射，结合碰撞电离和杂质光伏（PV）效应，并在完全优化后利用周围环境的红外线光子。
Thin film solar cells based on cadmium telluride (CdTe) are complex devices which have great potential for achieving high conversion efficiencies. Lack of understanding in materials issues and device physics slows down the rapid progress of these devices. This paper combines relevant results from the literature with new results from a research programme based on electro-plated CdS and CdTe. A wide range of analytical techniques was used to investigate the materials and device structures. It has been experimentally found that n-, i- and p-type CdTe can be grown easily by electroplating. These material layers consist of nano-and micro-rod type or columnar type grains, growing normal to the substrate. Stoichiometric materials exhibit the highest crystallinity and resistivity, and layers grown closer to these conditions show n -> p or p -> n conversion upon heat treatment. The general trend of CdCl2 treatment is to gradually change the CdTe material's n-type electrical property towards i-type or p-type conduction. This work also identifies a rapid structural transition of CdTe layer at 385 +/- 5 degrees C and a slow structural transition at higher temperatures when annealed or grown at high temperature. The second transition occurs after 430 degrees C and requires more work to understand this gradual transition. This work also identifies the existence of two different solar cell configurations for CdS/CdTe which creates a complex situation. Finally, the paper presents the way forward with next generation CdTe-based solar cells utilising low-cost materials in their columnar nature in graded bandgap structures. These devices could absorb UV, visible and IR radiation from the solar spectrum and combine impact ionisation and impurity photovoltaic (PV) effect as well as making use of IR photons from the surroundings when fully optimised.