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arXiv 1401.6993cond-mat.mtrl-sci
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混合卤化物钙钛矿光伏吸收体的相对论准粒子自洽电子结构

Relativistic quasiparticle self-consistent electronic structure of hybrid halide perovskite photovoltaic absorbers

Federico Brivio, Keith T. Butler, Aron Walsh, Mark van Schilfgaarde

摘要:

基于有机金属卤化物钙钛矿CH $_3$ NH $_3$ PbI $_3$的光吸收层的太阳能电池最近已经达到15%的转换效率,尽管这些材料如何工作仍然在很大程度上未知。在准粒子自洽GW近似下分析了电子结构和光学性质。虽然这种化合物与传统的sp半导体有一些相似之处,但它也显示出独特的特性。准粒子自洽性对于精确描述能带结构是必不可少的:带隙比局域密度近似(LDA)或基于LDA的GW预测的要大得多。价带色散以一种非常不寻常的方式被改变。此外,自旋轨道耦合强烈修改的能带结构,并引起非常规的色散关系和Dresselhaus分裂的带边。平均空穴质量很小,这是最近观察到的长扩散长度的原因。表面电离电位(功函数)计算为5.7 eV相对于真空水平,解释有效的载流子转移到TiO $_2$和Au电接触。

英文摘要:

Solar cells based on a light absorbing layer of the organometal halide perovskite CH$_3$NH$_3$PbI$_3$ have recently reached 15% conversion efficiency, though how these materials work remains largely unknown. We analyse the electronic structure and optical properties within the quasiparticle self-consistent GW approximation. While this compound bears some similarity to conventional sp semiconductors, it also displays unique features. Quasiparticle self-consistency is essential for an accurate description of the band structure: bandgaps are much larger than what is predicted by the local density approximation (LDA) or GW based on the LDA. Valence band dispersions are modified in a very unusual manner. In addition, spin orbit coupling strongly modifies the band structure and gives rise to unconventional dispersion relations and a Dresselhaus splitting at the band edges. The average hole mass is small, which accounts for the long diffusion lengths recently observed. The surface ionisation potential (workfunction) is calculated to be 5.7 eV with respect to the vacuum level, explaining efficient carrier transfer to TiO$_2$ and Au electrical contacts.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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