Institute of Engineering Research, Jeonju University, Hyoja-dong, Wansan-ku, Chonju, Chonbuk 560-759, South Korea.
J Chem Phys. 2011 Mar 7;134(9):094702. doi: 10.1063/1.3553475.
Using the first-principles calculations, we have investigated the stability and the electronic structure of two types of recently synthesized one-dimensional nanoribbons, i.e., double-stranded zinc(II) porphyrin ladder polymer (LADDER) arrays. First, electronic structure calculations were used to show that the LADDER is a semiconductor. Most importantly, the application of a transverse electric field significantly reduces the band gap of the LADDER, ultimately converting the LADDER to a metal at a field strength of 0.1 V∕Å. The giant Stark effect in this case is almost as strong as that in boron nitride nanotubes and nanoribbons. In the presence of an electric field, hole conduction and electronic conduction will occur entirely through spatially separated strands, rendering these materials useful for nanoelectronic devices. Second, the substitution of hydrogen atoms in the porphyrin units or that of zinc ions with other kinds of chemical species is found to increase the binding strength of the LADDER and reduce the band gap.
利用第一性原理计算，我们研究了最近合成的两种一维纳米带的稳定性和电子结构，即双链锌（II）卟啉梯形聚合物（LADDER）阵列。首先，电子结构计算表明 LADDER 是一种半导体。最重要的是，横向电场的应用显著降低了 LADDER 的能带隙，最终在 0.1 V/Å 的场强下将 LADDER 转变为金属。在这种情况下，巨大的 Stark 效应几乎与氮化硼纳米管和纳米带一样强。在电场存在的情况下，空穴传导和电子传导将完全通过空间分离的链发生，从而使这些材料在纳米电子器件中有用。其次，发现卟啉单元中的氢原子或锌离子的取代与其他化学物质的取代会增加 LADDER 的结合强度并减小能带隙。
