高效率倒置型高分子薄膜太阳能电池研究

Research on polymer solar cells has been intensified in recent years because polymer solar cells have a potential to generate electricity from sunlight at low cost.The typical device geometry of polymer solar cells comprises a bottom indium tin oxide (ITO) anode, a poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) anode interfacial layer, a bulk-heterojunction active layer and a low-work-function top metal cathode.This kind of polymer solar cells not only requires vacuum deposition of low-work-function metals, but also is concerned with the inherent device instability due to the hygroscopic and acidic nature of PEDOT:PSS.These problems will block the large-area roll-to-roll fabrication of polymer solar cells and their future commercial application.Inverted polymer solar cells have received a great deal of attention in recent years because of their compatibility with large-scale roll-to-roll processing and the potential for long-term stability.In this project, we propose to develop high power conversion efficiency inverted polymer solar cells without using PEDOT:PSS and low work-function metal cathode.The key point for constructing high-efficiency inverted polymer solar cells is to develop a highly transparent cathode interfacial layer coated on ITO to enhance electron extraction and restrain charge recombination.Solution-processible anode interfacial materials are also required to realize solution-processed roll-to-roll fabrication. It is anticipated that three or more solution-processible electrode buffer layers will be developed to construct high-efficiency inverted polymer solar cells.In addition, we propose to manipulate the donor/acceptor bulk heterojunction morphology by tuning the interaction between the fullerene acceptor and the underlying buffer layer.It is anticipated that the power conversion efficiency of the solution-processible inverted polymer solar cells can be improved to above 8% by using our electrode interfacial materials with intellectual property. 10 high-level scientific papers will be published and 3 chinese patents will be filed.

针对传统正置结构高分子薄膜太阳能电池普遍采用PEDOT:PSS(其吸湿性和弱酸性影响器件性能和长期稳定性)和低功函数金属(不易于实施大面积溶液加工)所面临的具体科学问题，提出开展高效率倒置结构高分子薄膜太阳能电池研究。本项目以提高倒置结构高分子薄膜太阳能电池的能量转换效率为核心目标，重点研究开发适合溶液加工技术的电极界面材料和界面技术，通过界面材料电子结构调控实现与活性层材料的欧姆接触，抑制界面载流子复合和提高电荷收集效率；调控界面层薄膜表面性质构建利于载流子传输的上层活性层的聚集态结构。获得适合大面积溶液加工技术的具有自主知识产权的界面材料和高效光伏电池制备技术。预期倒置光伏电池的能量转换效率达到8%以上，发表高水平学术论文10篇，申请中国专利3件。

本项目以提高高分子薄膜太阳能电池的能量转换效率为核心目标，重点研究开发适合溶液加工技术的电极界面材料和界面技术，抑制载流子界面复合和提高电荷收集效率,获得适合大面积溶液加工技术的具有自主知识产权的界面材料和高效光伏电池制备技术。取得的研究进展主要包括:(1) 提出利用超声化学法通过超声波促进溶胶-凝胶过程，在较低温度下制备出可溶液加工的NiO、CuO纳米粒子等阳极界面材料，旋涂成膜后界面层薄膜不需要高温后退火处理。利用这些可溶液加工的阳极界面材料代替传统PEDOT:PSS阳极界面材料制备了高效率有机光伏电池，光伏器件效率有所提高，同时器件的环境稳定性得到明显改善。(2) 以可溶液加工的ZnO纳米晶为基础，分别研发出光掺杂型醇溶性含膦酸酯共轭聚合物PF-EP/ZnO杂化阴极界面材料和电掺杂型镓掺杂ZnO(Ga-ZnO)阴极界面材料，光伏器件的性能对阴极界面层的厚度不敏感，光伏器件的最高效率达到10.04%。采用刮涂方法制备的印刷型聚合物太阳能电池效率达到7.56%。(3) 利用MoO3:Al/MoO3作为中间连接层制备出倒置结构PCDTBT:PC70BM同质结和PCDTBT:PC70BM/PDPP3T:PC70BM异质结叠层光伏电池，能量转换效率分别达到6.88%和7.31%，证实了功函数可调的MoO3:Al/MoO3结构作为叠层光伏电池中间连接单元的可行性。在项目执行期内，在Adv. Mater.、Adv. Funct.Mater.、ACS Appl. Mater. Interfaces、J.Mater. Chem. C、Sol. Energy. Mater. Sol. Cells等期刊发表标注资助项目号的SCI收录论文20篇，申请中国发明专利4件，其中授权专利2件。