【摘要】 本文为了理解由十环熔合非富勒烯受体和含有氟化苯三唑聚合物给体组成的有机光伏器件的优异光伏性能(光电转换效率大于13%),借助深入的量子化学计算,研究了氟化苯三唑聚合物给体、十环熔合非富勒烯受体及其异质结界面模型面-面相向构型复合物的几何结构、分子轨道、激发特性、分子表面静电势、转移电量和电荷转移距离.结果表明,氟化苯三唑聚合物给体:十环熔合非富勒烯受体异质结的卓越光伏性能是由于十环熔合非富勒烯受体分了内给体和受体片段之间的共面性,氟化苯三唑聚合物给体和十环熔合非富勒烯受体的电荷转移和杂化激发,在可见区域的互补光学吸收,以及从氟化苯三唑聚合物给体到十环熔合非富勒烯受体的分子表面静电势差值较大引起的.氟化苯三唑聚合物给体/十环熔合非富勒烯受体复合物的电子结构和激发表明,激子解离可以通过基于空穴转移的受体局域激发的衰退来实现,这不同于基于富勒烯受体的有机光伏的激子解离机理.通过Marcus理论评估的激子解离、电荷复合和电荷转移过程的速率常数表明有效的激子解离也是良好光伏性能的原因.更多还原

【Abstract】 Understanding organic photovoltaic(OPV)work principles and the materials’ optoelectronic properties is fundamental for developing novel heterojunction materials with the aim of improving power conversion efficiency(PCE) of organic solar cells. Here, in order to understand the PCE performance(>13%) of OPV device composed of the non-fullerene acceptor fusing naphtho[1,2-b:5,6-b′]dithiophene with two thieno[3,2-b]thiophene(IDCIC) and the polymer donor fluorobenzotriazole(FTAZ), with the aid of extensive quantum chemistry calculations,we investigated the geometries, molecular orbitals, excitations, electrostatic potentials, transferred charges and charge transfer distances of FTAZ, IDCIC and their complexes with faceon configurations, which was constructed as heterojunction interface model. The results indicate that, the prominent OPV performance of FTAZ:IDCIC heterojunction is caused by co-planarity between the donor and acceptor fragments in IDCIC, the the charge transfer(CT) and hybrid excitations of FTAZ and IDCIC, the complementary optical absorptions in visible region, and the large electrostatic potential difference between FTAZ and IDCIC.The electronic structures and excitations of FTAZ/IDCIC complexes suggest that exciton dissociation can fulfill through the decay of local excitation exciton in acceptor by means of hole transfer, which is quite different from the OPVs based on fullerenes acceptor. The rates of exciton dissociation, charge recombination and CT processes, which were evaluated by Marcus theory, support the efficient exciton dissociation that is also responsible for good photovoltaic performance.更多还原