高性能有机半导体材料设计新策略： 优化分子内硫-氧非共价键作用

Intramolecular non-covalent sulfur-oxygen interaction can effectively lock the conformation of organic semiconductors, which leads to high-degrees of backbone planarity, reduced bandgaps, enhanced materials crystallinities, and improved charge carrier mobilities. However, the usage of such non-covalent interactions in materials design suffers from the resonance effects of oxygen atoms on alkoxy chains, resulting in elevated energy levels of frontier molecular orbitals (FMOs). The high-lying FMOs greatly limit the open-circuit voltages and power conversion efficiencies of organic solar cells and leads to unsatisfactory device stabilities of organic thin-film transistors...In order to address the current limitations of materials design using intramolecular non-covalent sulfur-oxygen interactions, we design and synthesize a series of novel head-to-head linkage containing building blocks via optimizing the intramolecular sulfur-oxygen interactions. The optimization includes reducing the numbers of the sulfur-oxygen interaction, side chain engineering, and modification of the backbone arenes. These novel building blocks will be incorporated into polymer backbones. Materials innovation in combination with device engineering ensures the state-of-the-art device performance in both organic thin-film transistors and organic solar cells. We will thoroughly investigate the physicochemical property, opto-electrical characteristics, self-assembly, and film morphology of these novel building blocks and the resulting polymer semiconductors. Through various materials and device characterization techniques, the materials structure-property-device performance correlations will be established, which offer a new strategy for materials innovation in organic electronics.

分子内硫-氧非共价键作用能有效锁定有机半导体构象从而取得主链共面性、降低半导体带隙、提高材料结晶度、实现高迁移率。但由于烷氧链上氧原子的共振效应导致半导体前线轨道能级过高，限制有机太阳能电池的开路电压和能量转化效率, 导致晶体管稳定性不足。..为解决分子内硫-氧非共价键作用作为材料设计策略的不足，我们将合成一系列基于分子内硫-氧非共价键作用的头碰头单体，并对硫-氧作用深入优化，包括：（1）降低硫-氧作用数；（2）优化侧链基团；（3）改变芳环。这些新颖单体将用于构建高性能有机半导体。材料研发结合器件优化，本项目力争在有机场效应晶体管和有机太阳能电池领域取得具有国际先进水平的器件性能。我们将深入研究单体和高分子半导体的物理化学性质、光学和电子特性、自组装、及薄膜形貌结构。通过一系列材料和器件表征手段，本项目将建立材料的化学结构-性质-器件性能关系，为设计性能更优的有机半导体提供新策略。

有机和高分子半导体材料在有机电子器件中具有巨大的应用前景，优化分子内硫-氧非共价键作用是实现高性能有机半导体的重要材料设计策略。本项目以化学合成为基础，通过减少硫-氧作用数、优化侧链取代基团、改变芳环开发了一系列结构新颖的头碰头单体，包括单烷氧基单酯基的头碰头双噻吩、1,4-二烷氧基噻吩-2,5-二氟苯、基于酯基取代的二噻吩-噻吩并噻吩、基于硫-氧非共价键作用的酰亚胺、头碰头双呋喃、氰基取代头碰头双噻吩等。以这些新单体为构建单元，通过材料设计与不同电子受体聚合，合成了一系列具有良好溶解性、高共面和高结晶度的有机高分子半导体材料，系统地研究了各种含硫-氧作用的单体对材料性质及器件性能的影响。基于这些新颖单体所构建的有机半导体材料在有机场效应晶体管中取得了高迁移率，并在有机太阳能电池、钙钛矿太阳能电池中取得了优异的光伏性能。这些新单体与双氟和双氰基取代的苯并噻二唑受体单元所构建的高分子半导体在有机场效应晶体管中迁移率达1.5 cm2 V-1 s-1，基于分子内非共价键作用所构建的新型无掺杂空穴传输材料实现了效率高达21.1%的高性能反式钙钛矿电池器件，基于DOTFP的聚合物在有机太阳能电池中开路电压值达0.84 V，基于TETOR的高分子给体材料的有机太阳能电池填充因子达72.4%。这些结果为后续材料设计和器件优化提供了坚实基础和有力指导。.基于该项目，我们在国际高水平学术期刊上发表30篇学术论文；申请专利4项，授权2项；培养博士研究生1名，硕士研究生2名。