新型高效硅掺杂InAs/GaAs量子点中间能带太阳能电池的研究

As a new kind of battery device base on nano-structure, intermediate-band solar cell based on quantum-dot (QD-IBSC) has a theoretical efficiency of as high as 63.1%, which provides a potential and feasible way for efficient utilization of solar energy. However, the current efficiency of the device has not met people's expectations, as the device design and QD material preparation are still imperfect. Therefore, combined with the preliminary works, we propose a new technical route to improve the QD-IBSC's performance by Si-doping, that is to say, we will adjust the energy band structure and improve the QD material properties at the same time by Si-doping, to realize high-performance battery devices. .In this project, we will combine the mechanism researches of the QD material properties affected by Si-doping with the 8-band kop model theoretical simulations and study the controllable growth techniques and relevant physical mechanism of the high-quality InAs / GaAs self-assembled QD material， realizing the fine tuning of the properties and growth of the QDs. Meanwhile，we will also investigate the design and fabrication technology of high-efficiency Si-doping QD-IBSC, revealing the effect mechanisms and their intrinsic association of the dynamics processes related to carrier generation, transport and collection of Si-doped QDs intermediate-band. The results obtained by executing the project would offer theoretical basis and key technologies for developing the new-generation high-efficiency solar cells with proprietary technology, to meet the major strategic needs of our country to solve the energy problem.

量子点中间能带太阳能电池是一种基于纳米结构的新型器件，具有高达63.1%的理论效率，是高效利用太阳能的新途径。由于目前器件设计和量子点材料性能存在缺陷，器件效率偏低。针对影响其性能的关键问题，结合前期工作，本项目提出一种Si掺杂提高InAs/GaAs量子点中间能带太阳能电池性能的新技术路线，即通过Si掺杂技术同时调节器件能带结构和改善量子点材料性能，实现高效电池器件。.本项目从Si掺杂对量子点材料性能影响的机理研究出发，结合八带kop模型等理论模拟，开展高质量Si掺杂InAs/GaAs量子点材料的可控生长和相关机理研究，实现对其性能的精细调控。同时开展基于这一材料的高效中间能带太阳能电池设计和制备研究，揭示Si掺杂量子点中间能带对载流子产生、输运、收集等动力学过程的作用机理与内在关联，为发展具有自主知识产权的新一代高效太阳能电池提供理论基础和关键技术，满足国家解决能源问题的重大战略需求。

本项目紧密围绕提升量子点中间能带太阳能电池效率和综合性能这一重要科学问题，重点开展了高性能Si掺杂InAs/GaAs量子点材料的制备与物性、中间带对载流子输运特性的影响机理、新型高效量子点中间能带太阳能电池器件设计与制备等方面的研究，取得一系列重要的研究成果。.首先，我们对高性能Si掺杂InAs/GaAs量子点材料制备技术与物性进行了系统研究。结果表明，在量子点形成的自限制阶段引入适量Si掺杂，量子点材料中的载流子复合中心将被电子填充，从而大幅降低材料内部的载流子能量损耗，改善材料的光学质量。这为高性能电池器件的实现打下基础。其次，我们深入研究了中间带对载流子输运特性的影响，重点阐释了载流子寿命和中间能带性能这两个影响中间能带太阳能电池器件性能的关键因素。我们提出基于II类量子点材料提升中间能带太阳能电池器件性能的技术路线。结果表明，由于II类量子点中电子和空穴的输运通道彼此分离，载流子的寿命较I类量子点材料大幅提升，从而可进一步提升太阳能电池的输出特性，提高器件效率。同时，为精确控制量子点形貌，提升量子点能级耦合效率和中间能带质量，我们提出一种基于“线中点”结构的新型中间能带太阳能电池器件，将量子点材料嵌入形貌均匀、可控的纳米线阵列中，实现对量子点尺寸的精确控制。目前已实现无缺陷、纯相的高品质GaAs纳米线阵列和InAsSb纳米线的可控制备。再次，通过对量子点材料和器件的不断优化，我们制备出高性能的Si掺杂InAs/GaAs 量子点中间能带太阳能器件，效率达到17.0%，性能接近国际同类器件报道的最高值18.7%。.本项目至今发表学术论文6篇，其中一区文章2篇。本项目研究结果将对进一步提升量子点中间能带太阳能电池综合性能具有重要意义。.