D-σ-A型分子整流器的理论研究

采用DFT的方法分别对一系列有望成为分子整流器的共轭分子的几何及电子结构进行了理论计算。通过B3LYP／6—31G＊＊算法确定了电子供体（Donor）和受体（Acceptor）分子。为使单分子整流器可在较大偏压下使用，尝试了不同的键桥结构。计算结果表明，分别作为供体和受体分子的硝基苯、苯胺之间具有最大的LUMO能级差。D-σ-A型分子中，电子最低未占据轨道（LUMO）局限在分子的受体片段上，而电子最高占据轨道（HOMO）局限在供体片段上。受体和供体片段之间的键桥结构为-CH2CH2CH2CH2-时，分子的势能差最大，为2．47eV。

Theoretical studies on D-σ-A type molecular rectifiers

Density functional theory (DFT) was adopted to calculate the geometric and electronic structures of a series of conjugated molecules, candidates for molecular rectifiers, aiming at the acquirement of potential molecular rectifiers. The individual donor and acceptor molecules were determined by B3LYP/6-31G method. Different spacers were also tried to get molecular rectifiers for a wide range of bias voltages. The calculations show that the largest LUMO difference is occurred between nitrobenzene (Donor) and aniline (Acceptor). LUMO is localized on the acceptor ring, while HOMO is localized on the donor ring in the D-a-A type molecule. The molecular potential difference is achieved to be the largest, 2. 47eV, when the spacer is - CH2CH2CH2CH2 -.