三元有机光伏器件的界面结构与光电性能优化

Ternary organic solar cells have emerged as a promising breakthrough to achieve the high power conversion efficiency. However, its fundamental knowledge on the ternary interfacial electronic structures and optoelectronic conversion properties remains unclear, which limits the further development of material and device design. The research topic is the foreland of organic electronics. Focusing on interface physical properties at organic semiconductor interfaces, we have developed several interface design rules for organic optoelectronic devices with high efficiency. In the proposed project, we will study the interfacial formation principles, electronic structures and energy transfer processes in the type of three component organic heterojunction interface, which enable us to obtain the relationship between the interfacial energetics and the photoelectronic conversion in ternary organic solar cells. The project aims to reveal the physical mechanism of tailoring organic ternary interface properties and thus achieve high performance organic ternary solar cells. In the methods, we employ photoelectron spectroscopy and synchrotron radiation techniques for interface in-situ、real-time characterization in combination with precision optical spectroscopy and device fabrication for photoelectric conversion property. The research will achieve innovative results in the key physical and technical issues of the novel organic ternary solar cells, e.g. device structure, working mechanism and fabrication process.

三元有机光伏电池有望成为实现高效太阳能电池的重要突破口，然而对其关键界面电子结构、光电转换等界面物性的认识并不清晰，制约了材料设计和器件开发向更高层次的发展，相关研究是当今有机电子领域的前沿。申请者围绕有机半导体界面物性开展了系列工作，提出了若干高效有机光电器件界面设计原则。本项目致力于研究三元有机光伏器件中三元有机异质结界面形成机理、电子结构、动态过程，探索界面物性与光电转换过程的构效关系，揭示光电功能调控的物理机制，在此基础上，发展界面调控的新方法，实现高效三元有机光伏器件。研究方法上，将采用光电子能谱、同步辐射技术对有机界面进行原位、实时表征，并且结合精密光谱、器件构筑对光电性能开展研究。通过本项目的实施，力争在新型三元有机光伏电池所涉及的器件结构、工作机理、加工工艺等关键物理与技术问题上取得创新成果。

三元有机光伏电池有望成为实现高效太阳能电池的重要突破口，然而对其关键界面电子结构与光电转换等物性的认识并不清晰，制约了器件效率的提升。本项目研究了三元有机异质结界面电子结构特性，建立了界面调控光电转换的新方法，实现了高效有机光伏器件，取得了一系列成果，包括：(1)揭示了三元有机异质结界面精细电子结构特性，通过界面ICT电子态精密调控，促进电荷传输，实现了填充因子为81.3%的三元有机光伏器件，该填充因子是目前已报道的三元有机光伏电池的最高值。(2)引入受体ITIC-M作为第三组分，匹配界面电子结构，优化活性层形貌，实现了光电转换效率为18.13％，填充因子为80.10％的三元有机光伏器件，该效率是目前已报道的PM6:Y6体系三元有机光伏器件的最高值。(3)利用稳定的n型掺杂剂DMBI-BDZC掺杂PM6:Y6二元体系，实现了器件光电转换效率从17.17%大幅提升至18.33%，填充因子为80.2%。(4)揭示了准二维有机-无机杂化钙钛矿与电子传输层PCBM的n-n结特性，纠正了传统p-n型异质结的错误认知。(5)发现了钙钛矿半导体表面电子结构从p型转变成n型的新现象，实现了光电转换效率为21.88％和填充因子为83.81％的钙钛矿光伏器件，这两个数值均是当时文献已报到的多晶MAPbI3的p-i-n结构器件的最高值。本项目取得了预期的研究成果，为实现高性能光伏器件提供了理论指导和技术借鉴。