Department of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Dalton Trans. 2011 May 28;40(20):5563-8. doi: 10.1039/c0dt01601b. Epub 2011 Apr 14.
The structural and electrical properties of a metal-halide cubic perovskite, CH(3)NH(3)SnI(3), have been examined. The band structure, obtained using first-principles calculation, reveals a well-defined band gap at the Fermi level. However, the temperature dependence of the single-crystal electrical conductivity shows metallic behavior down to low temperatures. The temperature dependence of the thermoelectric power is also metallic over the whole temperature range, and the large positive value indicates that charge transport occurs with a low concentration of hole carriers. The metallic properties of this as-grown crystal are thus suggested to result from spontaneous hole-doping in the crystallization process, rather than the semi-metal electronic structure. The present study shows that artificial hole doping indeed enhances the conductivity.
我们研究了卤化金属钙钛矿 CH(3)NH(3)SnI(3) 的结构和电学性质。通过第一性原理计算得到的能带结构显示费米能级处有明确的带隙。然而，单晶电导率的温度依赖性在低温下表现出金属行为。整个温度范围内热电势的温度依赖性也是金属的，并且大的正值表明电荷输运是通过低浓度的空穴载流子发生的。因此，这种生长晶体的金属性质被认为是由于在结晶过程中自发的空穴掺杂，而不是半金属的电子结构。本研究表明，人工空穴掺杂确实可以提高电导率。
