有机太阳能电池石墨烯双层界面修饰研究

The commercial applications of organic solar cell (OSC) are retarded by its low power conversion efficiency (PCE) and short lifetime, which can be further improved by interfacial modification on. In previous researches, we have demonstrated that double-layer interfacial modification is better than single layer modification either on the PCE or stability of OSC. The graphene has been widely applied to modify the cathode and anode of OSC. However, the high impedance of graphene layer is not benefit to the PCE of OSC and it is hard to improve the performance of OSC by using single layer graphene. Hence, double-layer interfacial modification based on graphene material as we proposed in this project might be the solution. Through the experimental optimization the double-layer modification and theoretical understanding its effect on the transport of the electrons and holes at interface, new type OSC with high performance can be developed. In this project, to achieve high efficient and stable OSC, polyethylenimine ethoxylated(PEIE)，molybdenum disulfide (MoS2), molybdenum trioxide (MoO3), as well as metal nanoparticles will be combined with graphene to fabricate double-layer modification between cathode-organic, anode-organic and organic-organic interfaces, respectively in order to enhance the transporting efficiency of electrons or holes and dissociation of excitons. Meanwhile in this project the dynamic processes at OSC interfaces can be studied based on this double-layer interfacial modification. This study is important to understand the interfacial processes of OSC for fabricating high-efficient OSC devices.

效率低和寿命短是制约有机太阳能电池（OSC）产业化的主要原因，而界面优化又是制约OSC效率和寿命的关键。我们前期研究表明，通过界面修饰能有效提升OSC的效率和稳定性，并在双层界面修饰中表现优异。目前，石墨烯已广泛应用到电极单层界面修饰中，但与之带来的高阻抗和厚度依赖又制约了OSC的性能提升。因而实验发展石墨烯双层界面修饰的工艺，理论弄清电子和空穴产生和输运的机制是OSC研发的一个重要突破口。本项目拟采用石墨烯分别与PEIE、MoS2/MoO3和金属纳米颗粒结合，作为双层阴极、阳极和有机界面层的修饰材料，分别提升电子、空穴传输速率和激子拆分效率，最终获得高效、稳定的OSC器件。通过研究上述双层界面修饰对激子拆分和电荷传输过程的影响，以期准确描绘OSC界面的动力学机制。本项目的研究对完善OSC界面机理过程和提高转换效率有重要意义。

效率低和寿命短是制约有机太阳能电池（OSC）产业化的主要原因，而界面优化又是制约OSC效率和寿命的关键。我们前期研究表明，通过界面修饰能有效提升OSC的效率和稳定性，并在双层界面修饰中表现优异。为了克服单层界面的不足，本项目系统研究了双层界面对电池性能和稳定性的影响，并研究了界面修饰对界面过程带来的影响。本项目采用钠功能化氧化石墨烯，降低了其薄膜功函数，促进电荷的传输，提高电池的效率；利用NaCl/PEIE（聚乙氧基乙烯亚胺）的双层电子传输层在OSC中减少界面接触电阻，促进电子在界面的传输；应用MoO3/NPB作为OSC双层界面修饰材料，不仅提高了电池中电荷的传输，也促进了激子在界面的拆分，最终获得高效、稳定的OSC器件；通过界面的修饰和优化对激子到自由载流子机理过程的研究，发现了回流电子的存在和获得界面激子和空穴相互作用获得自由载流子新途径；在增强界面激子相互作用的探索中，通过引入界面修饰层促进了界面激子与激子相互作用，获得更高效的拆分效率；提出采用瞬态光电流技术研究界面激子和电荷的动力学过程。本项目建立的研究方法和思路拓展研究了钙钛矿太阳能电池，获得高效的钙钛矿太阳能电池。完成该项目的研究申请了3件OSC方面的国家发明专利和发表了9篇高质量SCI收录的学术论文。本项目的研究对完善OSC界面机理过程和提高转换效率有重要意义。