关键词: 结构转变方式, 光致变色, 电子传递, 电流开关比, 分子轨道

Abstract: A series of model molecules with 4 kinds of conformational transformations have been investigated as optical molecular switches by using density functional theory combined with nonequilibrium Green’s function method. The theoretical calculations show that molecules after conformational transformations have photoswitching characteristics. We find that the photochromic molecules with the same conformational transformation usually have a similar current on/off state when they are applied as photoshwitches. Among these transformations, the molecular switch with E(“trans”)/Z(“cis”)-isomerisation of the NN double bond has the highest current on-off ratio. The influences of the energy gap (HLG) between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), spatial distributions, transmission and projected density of states (PDOS) spectra on the electronic transport through the optical molecular switches are discussed in detail.

Key words: conformational transformation, photochrome, electronic transport, current on-off ratio, molecular orbitals