Electronic structure of chainlike polysilane
Electronic structure of chainlike polysilane
复制标题
链状聚硅烷的电子结构
DOI：
10.1021/ja00286a012
复制
发表时间：
1986
影响因子：
15
通讯作者：
N. Matsumoto
中科院分区：
文献类型：
--
作者：
K. Takeda;H. Teramae;N. Matsumoto
计算了模型化合物-（SiXY-）n聚硅烷的能带结构，其中X和Y是H，Me，Et，Pr和Ph（苯基）取代基.聚硅烷具有直接允许的带型结构，并且允许-* 带间光学跃迁。带边态主要由骨架Si AO（原子轨道）形成，这导致骨架带隙。当较大的烷基取代侧链时，这种骨架带隙趋于减小。和 * 带边态在骨架轴上有很好的离域。具有Ph侧链的聚硅烷[聚（芳基硅烷）]由于Si骨架和Ph侧链之间的混合而表现出特征的带边结构。这种相互作用消除了双简并的Ph t-HOMO态。其中一个态与骨架-价带态混合，沿骨架轴沿着离域。另一个仍然强烈地定位在单个Ph侧链中。然而，在导带边缘没有 *-* 混合发生，并且在导带结构中没有看到变化。这导致未被占据的局域态在骨架带隙中的侵入。
Energy bandstructures are calculated for-(SiXY-)„polysilane, model compounds in whichX and Y are H, Me, Et, Pr, and Ph (phenyl) substituents. Polysilane has a directly allowed typeband structure, and a-* interband optical transition is allowed. Band-edge states are formed mainly of skeleton Si AOs (atomic orbitals), which results in a skeleton band gap. This skeleton band gap tends to be reduced whenlarger alkyl groups are substituted for side chains. The and* band-edge states are well delocalized on the skeleton axis. Polysilanewith Ph side chains [poly (arylsilane)] exhibits a characteristic band-edge structure due to- mixing between the Si skeleton and Ph side chains. Thisinteraction removes the doubly degenerated Ph t-HOMO states. One state is mixed with theskeleton-valence band state and delocalized along the skeleton axis. The other remains strongly localized in the individual Ph side chains. However, no*-* mixing occurs at the conduction band edge, and no change is seen in the conduction band structure. This results in the intrusion of unoccupied localized states in the skeleton band gap.