论文标题
无序的电子和无定形TiO2中的孔捕获
Disorder-induced electron and hole trapping in amorphous TiO2
论文作者
论文摘要
无定形（A）-TiO2的薄膜无处不在，如光催化剂，保护性涂层，光射流和记忆应用中，它们会暴露于多余的电子和孔中。我们使用混合密度功能理论（H-DFT）计算研究了大部分纯二氧化二氧化钛A-TIO2中过量电子和孔的捕获。使用经典分子动力学及其几何形状，使用H-DFT模拟对其几何形状产生了五十270-ATOM A-TIO2结构。它们具有与实验一致的原子配位数和径向对分布函数的密度，分布。计算出的平均A-TIO2频带隙为3.25 eV，没有状态分裂到频带隙中。预测在前体位点（例如细长的Ti-O键）预测过多的电子和孔在A-TIO2中的捕获。单电子和孔极化子的平均捕获能（ET）分别为-0.4 eV和-0.8 eV。我们还确定了几种类型的电子和双孔状态，并讨论其稳定性。这些结果可用于理解光催化的机制，并改善采用A-TIO2膜的电子设备的性能。
Thin films of amorphous (a)-TiO2 are ubiquitous as photocatalysts, protective coatings, photoanodes and in memory application, where they are exposed to excess electrons and holes. We investigate trapping of excess electrons and holes in the bulk of pure amorphous titanium dioxide, a-TiO2, using hybrid density functional theory (h-DFT) calculations. Fifty 270-atom a-TiO2 structures were produced using classical molecular dynamics and their geometries fully optimised using h-DFT simulations. They have the density, distribution of atomic coordination numbers and radial pair-distribution functions in agreement with experiment. The calculated average a-TiO2 band gap is 3.25 eV with no states splitting into the band gap. Trapping of excess electrons and holes in a-TiO2 is predicted at precursor sites, such as elongated Ti-O bonds. Single electron and hole polarons have average trapping energies (ET) of -0.4 eV and -0.8 eV, respectively. We also identify several types of electron and hole bipolaron states and discuss their stability. These results can be used for understanding the mechanisms of photo-catalysis and improving the performance of electronic devices employing a-TiO2 films.
