铜铟镓硒柔性太阳电池双重调控模式的构建及其对效率和柔性兼容机制的影响

High efficiency along with good flexibility is the key to the development of flexible solar cells. The development of CIGS flexible solar cells is limited by inadequate high temperature resistance of the flexible substrate, Na element missing, and poor flexibility of the top electrode. The construction of a high-quality light-absorbing layer and the search for an alternative with good flexibility for the top electrode are the effective means to solve the above-mentioned issues. The project intends to adopt a dual regulation model from both the back substrate and top electrode. Based on the selection and control of the substrate, and the replacement and optimization of the top electrode, CIGS solar cell with ultra-flexibility and high efficiency will be realized. Through the introduction and diffusion of a high-solubility KCl layer, a (Na， K) co-doping system will be constructed to address the issues of inadequate high temperature resistance and Na diffusion missing caused by the flexible substrate, to obtain a compact, large crystal, high-quality flexible CIGS absorption layer. A silver wire/chitosan top electrode will be composited through a combination process of node welding and protective layer introduction, to achieve a synchronous improvement of efficiency and flexibility on CIGS photovoltaic devices. The regulation and combining parameters of the substrate and the top electrode will be studied in detail on the effect of the performance of flexible CIGS solar cells, along with their mutual relationship, which provides theoretical basis and technical support for the development of high efficiency and good flexible solar cells.

高效率和良柔性的统筹兼顾是柔性太阳电池发展的关键。柔性衬底不耐高温、Na元素缺失及顶电极柔性差是制约铜铟镓硒(CIGS)柔性太阳电池发展的主要障碍。高质量吸光层的构筑及良柔性顶电极替代品的探寻是解决上述难题的有效手段。本项目拟采用双重调控模式，即通过衬底的选择及调控、顶电极的替代及优化两者相结合的方式，实现CIGS太阳电池高效率和良柔性的兼容。通过高溶解度KCl层的引入，诱导碱金属的有效扩散，实现Na、K共掺体系的构建，试图解决柔性衬底存在的不耐高温、Na扩散缺失问题，构筑致密、大晶的高质量柔性CIGS吸光层；以银线为研究载体，通过结点焊接和保护层引入相结合的方式，构筑银线/壳聚糖复合顶电极，以实现CIGS太阳电池柔性及效率的同步提升。系统探究衬底和顶电极的调控形式和复合参数对CIGS太阳电池性能的影响，并揭示彼此之间的相互关系，为发展高效率和良柔性太阳电池提供理论依据和技术支撑。

在该项目的资助下，取得的主要研究成果包括：通过结点焊接和构筑复合物的双重优化方式，构筑AgNW/壳聚糖复合透明电极，有效解决银纳米线与底部附着力弱及其自身热稳定性和抗氧化能力差等问题，实现CIGS光伏器件的效率及稳定性的同步提高；采用绿色环保、简单可控的叠层电沉积工艺，制备高质量CZTSe吸收层，实现当时9.1%的最高光电转换效率，并将其复制到柔性Mo箔上，同时采用脉冲电化学方式引入MoOx层，抑制MoSe2的厚度，降低不良缺陷，逆转晶界性质，促进电荷的分离和收集，促使柔性CZTSe器件效率(6.33%)突破当时电沉积基最高效率的纪录(3.82%)；通过Se-GeSe2共硒化方式，构筑浅梯度高质量磁控溅射基CZTSe光伏器件，抑制不良缺陷，改善晶界质量，优化CdS/CZTSe的能带排列。本项目推动了铜基薄膜太阳能电池的快速发展，也为无机柔性光伏器件的应用提供了良好借鉴。在本项目的支持下，发表了与该项目密切相关的论文6篇，授权国家专利2项。