基于苯并噻吩平面格的张力与重组能的理论研究

Theoretical Study on the Strain Energy and Reorganization Energy Based on Planar Grid Benzothiophene

有机半导体材料在有机发光二极管(OLED)、有机场效应晶体管(OFET)和有机太阳能电池(OSC)等领域应用广泛,但由于各类结构缺陷和迁移率较低,不利于载流子的传输.本文基于苯并噻吩设计并研究了一系列新型有机电荷传输纳米分子,利用密度泛函理论研究了分子轨道、电离能、电子亲和势、张力能和重组能等分子结构和电子性质;利用约化密度梯度函数和正规模式(NM)分析方法计算了分子内的弱相互作用和每个振动模式对重组能的贡献.结果表明,苯并噻吩格子化(形成四元格)之后,与其单体相比,分子的电子重组能降低了至少0.394 eV,空穴重组能降低了至少0.056 eV,证明格子化是降低重组能的一种有效策略.

Organic semiconductor materials are widely used in organic light-emitting diodes(OLEDs),organic fieldeffect transistors(OFETs),and organic solar cells(OSCs),but they still have some defects,such as poor mobility,which are not conducive to electron transport.In this paper,a series of novel organic charge-transporting nanomole⁃cules were designed and studied based on benzothiophene.Then the molecular structure and electronic properties were studied by using density functional theory,such as molecular orbitals,electrostatic potential,ionization potential,electron affinity,and reorganization energy.Furthermore,intramolecular weak interactions and the contribution of each vibrational mode to the reorganization energy were estimated using non-covalent interaction(NCI)analysis and normal mode analysis,respectively.The results showed that the reorganization energy decreased with the increase of benzothiophene and gridization effect.Compared with the monomer,the electron and hole reorga⁃nization energies were reduced by at least 0.394,and 0.056 eV,respectively,which proves that gridization effect is an effective way to reduce the reorganization energy.