Interfacial Engineering of Solution-Processed Thin-Film Photovoltaic Devices

溶液处理薄膜光伏器件的界面工程

• 批准号: 2610807
• 金额: --
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2610807
• 关键词: Interfacial; Engineering; Solution; Processed; Thin

The UK has set a legally binding target of net carbon zero by 2050 in every aspect of the economy and delivering sustainable and green solar electricity generation will be crucial in this transformation. Crystalline Si currently dominates the solar industry, representing approximately 95 % of the solar modules sold today. However, due to its low photon absorption coefficient and indirect bandgap, thicknesses up to 350 m are needed, making crystalline Si unsuitable for thin-film applications. Thin-film photovoltaic (PV) materials on flexible substrates will allow for the integration of solar energy conversion in buildings and infrastructure in urban environments, which is a key area of expansion in solar energy to meet required environmental targets. Cu2ZnSn(S,Se)4 (CZTSSe) is a non-toxic, inorganic thin-film material with desirable PV properties due to its tuneable direct bandgap between 1.0 - 1.5 eV and 20 % theoretical power conversion efficiency (PCE) under AM1.5G illumination. However, CZTSSe is currently limited by significant voltage losses, which have been linked to structural disorder including antisites defects, secondary phases, and point defect clusters, hindering the PCE. This PhD is part of a collaboration between the universities of Bristol, Northumbria and Loughborough on the SolPV project, funded by EPSRC, and industrial partners of Centre of Process Innovation, Johnson Matthey, BAE systems and M-Solv. The main purpose of this PhD is to perform interfacial engineering of the p-n junction between the CZTSSe absorber layer and buffer layer, using atomic layer deposition, to achieve record breaking efficiencies of greater than 15 %. CdS has been extensively used as a buffer layer for CZTSSe solar devices as it is an established buffer material for the most advanced technology of CuInxGa1-x(S,Se)2 (CIGS). Although CdS has worked as an efficient buffer layer in both CZTSSe and CIGS, Cd is toxic and cannot be released into the environment, therefore, a suitable replacement is required. In- and Zn-based oxysulfide alternatives will be investigated as possible replacements. Another aim of the project is to control crystallisation and composition of the absorber material and reduce the formation of detrimental defects, deep Sn trap states and carbon impurities by optimising the fabrication methodology. Bulk and surface composition and structure of the thin-films will be examined by electron microscopy techniques, Raman microscopy and Energy-Filtered Photoemission electron microscopy (EF-PEEM). EF-PEEM can provide surface electronic mapping of local effective work functions at the absorber-buffer junction, allowing for unique and vital electronic information. The focus of this research will be to confirm the PCE of CZTSSe solar cells will go beyond 15 %, while also using scalable manufacturing routes to ensure a smooth transition into industrial applications. This project falls within the EPSRC 'Solar Technology' research area.

英国制定了到 2050 年在经济各个方面实现净碳零排放的具有法律约束力的目标，而提供可持续的绿色太阳能发电对于这一转型至关重要。晶体硅目前在太阳能行业占据主导地位，约占当今太阳能组件销售量的 95%。然而，由于其低光子吸收系数和间接带隙，需要高达350 m的厚度，使得晶体硅不适合薄膜应用。柔性基板上的薄膜光伏（PV）材料将允许将太阳能转换集成到城市环境中的建筑物和基础设施中，这是太阳能扩展以满足所需环境目标的关键领域。 Cu2ZnSn(S,Se)4 (CZTSSe) 是一种无毒无机薄膜材料，具有理想的光伏性能，因为其直接带隙可在 1.0 - 1.5 eV 之间调节，并且在 AM1.5G 下理论功率转换效率 (PCE) 为 20%照明。然而，CZTSSe 目前受到显着电压损失的限制，这与反位点缺陷、二次相和点缺陷簇等结构紊乱有关，阻碍了 PCE。该博士学位是布里斯托大学、诺森比亚大学和拉夫堡大学在 SolPV 项目上合作的一部分，该项目由 EPSRC 以及工艺创新中心、庄信万丰、BAE Systems 和 M-Solv 等工业合作伙伴资助。该博士的主要目的是利用原子层沉积对 CZTSSe 吸收层和缓冲层之间的 p-n 结进行界面工程，以实现大于 15% 的破纪录效率。 CdS 已广泛用作 CZTSSe 太阳能器件的缓冲层，因为它是最先进的 CuInxGa1-x(S,Se)2 (CIGS) 技术的既定缓冲材料。尽管 CdS 在 CZTSSe 和 CIGS 中都可以作为有效的缓冲层，但 Cd 有毒并且不能释放到环境中，因此需要合适的替代品。将研究基于 In 和 Zn 的硫氧化物替代品作为可能的替代品。该项目的另一个目标是通过优化制造方法来控制吸收材料的结晶和成分，并减少有害缺陷、深锡陷阱态和碳杂质的形成。薄膜的本体和表面成分和结构将通过电子显微镜技术、拉曼显微镜和能量过滤光电发射电子显微镜（EF-PEEM）进行检查。 EF-PEEM 可以提供吸收器-缓冲器连接处局部有效功函数的表面电子映射，从而获得独特且重要的电子信息。这项研究的重点将是确认 CZTSSe 太阳能电池的 PCE 将超过 15%，同时还使用可扩展的制造路线以确保顺利过渡到工业应用。该项目属于 EPSRC“太阳能技术”研究领域。