K、Na共掺对柔性衬底CIGS薄膜表面、异质结界面微区调控的机理研究

Flexible Cu(In,Ga)Se2 (CIGS) thin film solar cells on polyimide (PI) sheet have attracted more attentions because of the widely demands in terrestrial and space photovoltaic applications due to its higher conversion efficiency (specific power W/kg ), tolerance against high energy radiation, long-time stability. Currently, CIGS thin film solar cell on PI foils with high efficiency beyond 20% has been achieved by the co-evaporation process at low substrate temperature. However, the mechanism of action of potassium and sodium doping and its function on the growth mechanism and the surface modification on flexible CIGS thin film needs to be investigated in further. In this project, we focus on the regulation of the surface micro-region and the formation of high-quality hetero-junction to study on the diffusion of all elements, surface modification and influence principle induced by K and Na doping in the CIGS films. Finally, it is expected to establish the theoretical and experimental basis in the flexible CIGS solar cell on PI in our nation by master the key technologies of improving CIGS film quality and formation of hetero-junction by low-temperature deposition via K and Na doping process.

柔性聚酰亚胺（PI）衬底Cu(In,Ga)Se2 (CIGS)薄膜太阳电池具有高光电转换效率、高重量比功率（W/Kg）、抗辐照能力强、长期稳定性等性能优点，在航空、航天领域及地面移动用电单位等方面需求广泛。目前，采用低温蒸发工艺在PI上制备CIGS薄膜太阳电池的光电转换效率已超过20%，但K、Na元素掺杂对CIGS薄膜作用机理以及界面修饰的原因还有待深入研究。本项目拟从CIGS薄膜表面微区调控及高质量CIGS/CdS异质结形成两个方面，对K、Na共掺杂下CIGS薄膜各元素扩散、CIGS薄膜表面修饰及改性CIGS薄膜的作用机制进行研究。掌握通过K、Na共掺杂提高低温沉积CIGS薄膜质量以及异质结质量的关键技术，为我国研发高效率PI衬底CIGS薄膜太阳电池提供理论和实验基础。

柔性铜铟镓硒（CIGS）薄膜太阳电池光电转换效率实验室记录已经达到了晶体硅电池高效率水平，受到了全世界光伏领域的高度关注，但目前仍有许多问题阻碍其产业化发展。针对碱金属素对CIGS薄膜作用机理以及界面修饰等问题，本项目提出K、Na共掺杂技术，并将其应用于柔性衬底化合物薄膜太阳电池。本项目首先制备具有一定含量的K、Na元素的金属Mo靶材，采用前掺杂工艺合理调控碱金属掺杂比例，平衡它对薄膜结构与电学性能的影响。通过揭示不同掺杂含量以及不同碱金属元素掺杂比例对吸收层性能的影响、原理和作用机制，提高了吸收层质量，并且解决了吸收层与背接触层之间的界面问题。研究碱金属K、Na以及Li元素对吸收层薄膜的影响，Mo/吸收层界面优化，制备了高效稳定的柔性衬底化合物薄膜太阳电池。