芴基张力半导体结构和光电性质的理论研究

摘要

通过对模型化合物环四-9,9'-二甲基-2,7-芴及其系列的环芴衍生物[n]CFs(n=3-8)的结构、张力能以及光电性质的研究来进一步探讨空间张力对材料光学及电学性质的影响.研究结果表明,随着化合物中芴基数量和直径的增加,张力能减小,能隙增大.具有相同芴基数目的环芴分子,随着分子中张力能减少,分子电离电势逐渐增加,而电子亲和能逐渐减小.通过对模型化合物的空穴和电子重整能研究发现,其数值很接近,说明该类材料是一类潜在的双极性传输材料.同时还发现[n]CFs中,随着张力的减少,其第二发射峰的波长发生了蓝移.综上所述,空间张力为设计多功能有机半导体材料提供了有力工具.%[4]Cyclo-9,9-dimethyl-2,7-fluorenylene ([4]CF) was used as a model compound to explore the steric strain effect on the structures and photoelectrical properties of materials.A series of strained cyclic polyfluorene materials,[n]CFs (n =3-8),was designed.It was found that the strain energy decreased and the energy gap increased as the number of n and ring diameter increased.The ionization potential and electronic affinity tended to increase and decrease as the strain energy decreased at the same number of [n]CFs,respectively.With a balance between hole and electron reorganization energies in the system,these compounds demonstrated great potential as ambipolar materials.It was also found that [n]CFs showed an obvious blue shift in their emission spectra wavelengths (,λem2) as the strain energy decreased.Steric strain provides a powerful tool for the design of multifunctional semiconductors in organic optoelectronics.