High Work Function Back Contacts for CdTe Solar Cells

知识优势：基于CdTe的薄膜电池由于其低成本和相对较高的转换效率（到目前为止约为16%）而具有广泛应用前景的前景之一。在这一点上，该领域有一个共识，即进一步显著提高效率需要改进光转换CdTe层的背接触。目前这种触点是用Cu制造的，由于Cu迁移到太阳能电池的CdTe层，随着时间的推移会受到降解的影响，以及由于CdTe/Cu边界上的非最佳电流传输而导致的转换效率有限。提出的研究将通过研究一类有前途的材料来解决这些问题，即层状复合金属，如VSe2或TiSe2。这些材料的特点是高化学惰性（这将减少或消除界面反应和迁移）和高功函数，这将优化转化效率。更广泛的影响：全球变暖和对外国能源的依赖重新引起了人们对替代能源的兴趣。光伏电池直接发电是一种最有前途的分散式清洁能源发电方式。然而，太阳能电池的商业可行性是与化石能源成功竞争的主要挑战之一。虽然CdTe薄膜太阳能电池目前被认为是最有可能广泛部署的候选者之一，但提高效率需要推动CdTe技术进入商业可行性领域，这是拟议研究的重点。在教育方面，本科生和高中生将与研究生一起参与该项目，让他们有机会亲身体验科学研究。

Intellectual Merit: CdTe based thin film cells have one of the most promising outlooks for wide-spread use due to their low cost and relatively high conversion efficiencies (~16%, to date). At this point, there is a consensus in the field, that further significant efficiency increases need an improvement of the back contact to the light converting CdTe layer. This contact is currently fabricated using Cu, which are affected by degradation over time due to migration of Cu into the CdTe layer of the solar cell, as well as limited conversion efficiency due to non-optimal current transport across the CdTe/Cu boundary. The proposed research will address these issues by investigating a promising class of materials, namely layered compound metals such as VSe2 or TiSe2. These materials distinguish themselves through high chemical inertness (which will reduce or eliminate interfacial reaction and migration) and high work functions, which will optimize the conversion efficiency.Broader Impact: Global warming and dependence on foreign energy sources have caused a renewed interest in alternative energy sources. Direct generation of electric power from photovoltaic cells is one of the most promising options to generate clean energy in a decentralized way. However, commercial viability of solar cells is one of the main challenges on the way to successful competition with fossil energy sources. While CdTe thin film solar cells are currently considered one of the most likely candidates for widespread deployment, increased efficiency is needed to push the CdTe technology into the realm of commercial viability, which is the focus of the proposed research. On the educational side, undergraduates and high school students will be involved in the program working together with the graduate students, giving them an opportunity to experience scientific research hands-on.