Development of Novel Silole-based Acceptor toward Organic Photovoltaic Cells

高性能n型有机半导体的稀缺性一直是有机电子学研究领域的主要问题。本研究通过对环三烯和环四烯及其硅桥衍生物的电子性质进行理论研究，探索n型有机半导体的新分子框架。理论量子计算表明，硅桥接环三乙烯和环四乙烯的LUMO能级分别低于相应的非桥接化合物。此外，硅桥化合物在中性态和自由基阴离子态之间的电子转移过程的重组能分别为0.334和0.232 eV，这是影响跳跃机制中电子转移效率的重要因素。这些特征可能有利于电子在固态中从自由基阴离子转移到相应的中性物质。

The rarity of high-performance n-type organic semiconductors still remains major issue in the research field of organic electronics. In this work, we performed theoretical study on the electronic properties of cyclic tri- and tetrathienylene and their Si-bridged derivatives to explore new molecular framework of n-type organic semiconductors. Theoretical quantum calculations revealed that the LUMO levels of Si-bridged cyclic tri- and tetrathienylenes are both lower than those of the corresponding not-bridged compounds, respectively. Moreover, the reorganization energies for electron-transfer processes of between neutral and radical anion state of Si-bridged compounds, which are important factors affecting efficiency of the process in a hopping mechanism, were estimated to be 0.334 and 0.232 eV, respectively. These features may be advantageous for electron transfer from radical anions to the corresponding neutral species in the solid states.