Heffner Herman, Marchetti Jorge Mario, Faccio Ricardo, López-Corral Ignacio
Instituto de Química del Sur (INQUISUR, UNS-CONICET), Departamento de Química, Universidad Nacional del Sur, Av. Alem 1253, B8000CPBBahía Blanca, Argentina.
Faculty of Science and Technology, Norwegian University of Life Sciences, Drøbakveien 31, 1430Ås, Norway.
Inorg Chem. 2022 Dec 5;61(48):19248-19260. doi: 10.1021/acs.inorgchem.2c02933. Epub 2022 Nov 20.
The introduction of defects is one of the most recurrent pathways to generate modifications to materials' electronic structure and surface reactivity. In this work, calculations based on the density functional theory (DFT) were applied to study the electronic properties of pristine and reduced TiO(B)(100) ultrathin sheets to evaluate their potential as a semiconductor material for dye-sensitized solar cells (DSSCs). It was carried out by introducing vacancy defects on these surfaces and then adsorbing a catechol molecule, used as a model of a direct electron injection sensitizer (type-II dye), in different interaction configurations. Geometric, energetic, and electronic analyses were performed, focusing on the electronic structure changes and charge transfer between the dye and surface during molecular adsorption. The obtained results seem to indicate that a thickness of four layers is adequate to obtain a satisfactory slab model approximation of the TiO(B)(100) surface. The presence of oxygen vacancy states among the majority of the reduced surfaces was observed as well as a reduction of the band gap energy value. Additionally, the adsorption of catechol in the reduced surface induced an increase in light absorption compared to the pristine model. These attributes suggest that reduced ultrathin sheets of TiO(B) could be a suitable candidate as a photoelectrode for DSSC applications.
引入缺陷是对材料电子结构和表面反应性进行改性的最常见途径之一。在这项工作中，基于密度泛函理论（DFT）的计算被用于研究原始和还原的TiO(B)(100)超薄片的电子性质，以评估它们作为染料敏化太阳能电池（DSSC）半导体材料的潜力。通过在这些表面引入空位缺陷，然后吸附用作直接电子注入敏化剂（II型染料）模型的儿茶酚分子，以不同的相互作用构型进行。进行了几何、能量和电子分析，重点关注分子吸附过程中染料与表面之间的电子结构变化和电荷转移。所得结果似乎表明，四层的厚度足以获得TiO(B)(100)表面令人满意的平板模型近似。在大多数还原表面中观察到氧空位态的存在以及带隙能量值的降低。此外，与原始模型相比，儿茶酚在还原表面的吸附导致光吸收增加。这些特性表明，还原的TiO(B)超薄片可能是DSSC应用中光电极的合适候选材料。
