活性层掺杂有机分子提高非富勒烯基聚合物太阳能电池的稳定性及其机理研究

At present, power conversion efficiency (PCE) of polymer solar cells (PSCs) has reached over 17%. Long term stability becomes the next key challenge before the commercialization of PSCs. The nanomorphology of the photoactive layer plays a key role in determining the performance and stability of PSCs. This project proposes to stabilize the interpenetrating network of active layer by doping organic molecular, and to focus on the mechanism study of stability and photovoltaic performance of organic active layer with organic molecules. Aiming at realizing the controllable construction of photoactive layer with high stability, this project will investigate as follows: 1) Degradation kinetics process of the PBDB-T:ITIC type high efficiency non-fullerene PSCs. Detailed nanomorphology and photoelectric performance of active layer will be characterized during the degradation. A relationship between active structure and stability of PSCs will be established. 2) Method to stabilize the nanomorphology of the photoactive layer. Two types of organic molecules (high crystalline polymer and molecule crosslinker) will used as additives in the photoactive layer to regulate the nanomorphology of the photoactive layer by π–π conjugated effect and chemical crosslinking effect. 3) Stability improvement of the PSCs. Based on the studying of the device stability changes of the solar cells with different molecule doping, a detailed mechanism of improving stability will be proposed, and a general process-structure relationship will be summarized. This project will provide a valuable theoretical guideline and technical support for the further degradation mechanism and stability improvements of PSCs.

目前，聚合物太阳能电池（PSCs）的光电转换效率已超过17%，但寿命短成为其实用化瓶颈。活性层结构态是决定PSCs稳定性的关键因素。本项目提出有机分子掺杂活性层稳定互穿网络结构的策略，围绕“有机分子结构对有机活性层的稳定性和光电性能的作用机制”的关键科学问题，实现高稳定性活性层的可控构建为目标，重点开展：1）系统研究PBDB-T:ITIC类高效非富勒烯基PSCs的衰减动力学过程，探索器件衰减过程中活性层形貌结构、光电性能的变化规律，建立活性层结构态与器件稳定性的关系；2）在活性层中掺杂高结晶共轭聚合物和交联有机小分子，利用π–π共轭作用和化学交联两种方式稳定活性层结构；3）通过研究有机分子掺杂过程中，器件稳定性的变化规律，揭示有机分子结构对活性层及其器件稳定性的作用机制，建立一种提高PSCs稳定性的新方法。本项目的实施将为PSCs衰减机理研究及其稳定性提升提供理论依据和技术支持。

目前，聚合物太阳能电池（PSCs）的光电转换效率已超过19%，但寿命短成为其实用化瓶颈。本项目首先通过系统研究高效非富勒烯基PSCs老化过程，揭示活性层中给受体材料相分离和界面老化是导致PSCs稳定性差的主要因素。针对PSCs两方面老化因素，一方面采用构建合金结构给受体体系和掺杂交联富勒烯三元分子两方面策略来冻结给受体体异质结结构，抑制受体小分子的迁移能力，最终有效提升了活性层的形貌稳定性，PSCs热稳定性大幅提升；另一方面设计合成ZnO@C核壳结构量子点界面材料替代ZnO用作PSCs阴极界面层，具有匹配能级、高疏水性和高抗紫外能力的ZnO@C，其表面疏水性碳壳不仅钝化ZnO表面缺陷同时降低空气中的水氧的侵蚀，还可提高PSCs抗紫外辐照能力，最终同步提升PSCs的紫外和空气稳定性。本项目不仅揭示了PSCs的衰减机理，而且开发了一系列交联富勒烯分子活性层稳定剂和新型碳包ZnO阴极界面材料，为实现高效、高空气和紫外稳定的PSCs提供了方法和理论指导。