自组装制备大面积界面修饰层及其在有机太阳能电池中的应用研究

Bulk-heterojunction organic solar cells (BHJ-OSCs) have drawn significant attention in both industrial and academic fields due to their several advantages, such as light weight, flexible, low cost and solution processability. Over the past few years, much progress had been made in improving the performance of OSCs, especially due to recent advance in non-fullerene acceptor, with power conversion efficiencies (PCEs) of close to 15% were achieved in small area device. As such, the performance of OSCs continues to increase, however scaling-up these devices from lab-scale device area to industrial-scale large areas remains a big challenge due to the efficiency losses associated with large area devices. One main reason is that, the optimal thickness of most reported interlayer materials should be precisely controlled, even a small variation in thickness often leads to a sharp decrease in device performance. To solve this problem, in this proposal, we aim at develop an easy and efficient approach to preparing large area interlayer with controlled film composition, uniformity and thickness at the nanometer-scale by using self-assembly technique. In which, the interaction between the interlayer materials and substrates, the compatibility of self-assembly technique with printing process, the working mechanism of interlayer in OSCs with different types of acceptors will be carefully studied. After that, we will apply these self-assembly films as interlayer in large area OSCs fabrication. And then, we will focus on the stability study of interlayer in OSCs device to find out the interlayer failure mechanism during the device operation and as a return, improve the stability. Through this project, we will not only get high quality large area interlayer film, but also gain deep understanding in interlayer working mechanism in different acceptor systems and interlayer failure mechanism.

有机太阳电池因具有质轻、柔性、低成本、可溶液加工等优点而成为研究的热点。目前实验室小面积器件的能量转换效率已经被推高至接近15%，已经接近其它类型太阳电池技术的效率水平，显示出巨大的商业化应用潜力。然而，大面积器件模组与小面积器件在效率上还存在较大的差距。其中一个主要因素在于，通过印刷方式加工大面积界面层时，由于印刷工艺通常会造成薄膜厚度出现较大程度的变化，很难实现在数个纳米甚至数十个纳米范围内均匀、平整、无针孔的连续薄膜。针对这一问题，本项目拟分别从大面积超薄均匀界面层的制备、工作机理和界面失效机制研究等方面出发，开发低成本制备大面积超薄均匀界面层的简易方法；深入研究界面层在不同受体活性层体系中的工作机理；研究多层薄膜的层间界面形态，界面层稳定性的影响因素和失效机制。最终，实现具有优异界面修饰性能的大面积界面层，并将其应用于大面积有机太阳电池的制备，加快有机太阳电池的商业化进程。

本项目分别从自组装大面积均匀界面修饰层的制备、工作机理及界面失效机制开展研究。开发了低成本制备大面积均匀界面层的简易方法，深入研究了界面层在不同受体活性层体系中的工作机理，界面层稳定性的影响因素和失效机制。另一方面，围绕印刷加工活性层形貌调控与大面积活性层制备开展了部分工作，通过抑制印刷过程中活性层的过度聚集，调控活性层与溶剂的溶剂-溶质相互作用，探求了获得旋涂和印刷相类似的活性层形貌。最终，结合自组装界面层和活性层形貌调控，发展了大面积有机太阳能电池，加快了有机太阳能电池的商业化进程。项目执行四年中共发表标注SCI论文20篇，包括Energy Environ. Sci., Adv. Energy Mater., Nano Energy等影响因子超过10.0的论文14篇。申请中国发明专利2项，获批1项。