Defect Engineering in ZnIn2X4 (X=S, Se, Te) Semiconductors for Improved Photocatalysis
Defect Engineering in ZnIn2X4 (X=S, Se, Te) Semiconductors for Improved Photocatalysis
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DOI：
10.1016/j.surfin.2023.102960
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发表时间：
2023-05
影响因子：
6.2
通讯作者：
M. Rahman;Jiaqi Yang;Yujie Sun;A. Mannodi-Kanakkithodi
中科院分区：
文献类型：
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作者：
M. Rahman;Jiaqi Yang;Yujie Sun;A. Mannodi-Kanakkithodi
ZnIn2S4由于其可见光吸收、化学和热稳定性以及低成本而成为一种感兴趣的基于掺杂剂的硫属化合物光催化剂材料。然而，ZnIn2S4的可见光吸收范围有限，太阳光诱导的空穴和电子的超快复合影响了其光催化活性。虽然以前的研究已经考虑了金属掺杂，金属沉积和空位工程对ZnIn2S4光催化活性的影响，但对本征点缺陷及其如何影响电子和光催化性能的全面了解仍然是难以捉摸的。在这里，我们提出了一个密度泛函理论（DFT）调查的缺陷能量在ZnIn2X4（X=S，Se，Te）化合物在体相和非晶相。使用半本地和混合DFT泛函，感兴趣的属性，如电子带隙和带边，光吸收光谱，载流子迁移率首先计算无缺陷的结构。虽然ZnIn2S4的吸收比其他硫族化合物低，但它具有足够的过电位用于光催化分解水的氧化和还原反应。所有可能的空位，自发光，和反位取代缺陷的形成能，然后计算所有结构，作为化学生长条件，电荷状态，和费米能级（EF）的函数，这导致识别的最低能量受体和供体类型的缺陷和它们相应的浅或深层次的性质。DFT结果表明，这些金属硫化物光催化剂易于ZnIn和InZn反位取代，这将平衡EF钉扎在导带边缘附近，指示n型导电性。虽然ZnIn不会在ZnIn2X4中产生深缺陷能级，但大多数稳定的原生缺陷确实会产生深能级，这可能会对太阳能吸收产生不利影响。最后，我们报告的缺陷的光催化析氢反应（HER）和析氧反应（OER）的影响，在ZnIn2X4。我们的研究结果表明，金属间隙缺陷可以大大提高HER和OER的表面上的ZnIn2X4。总体而言，这种系统的第一性原理研究可以帮助推动实验设计和缺陷工程的ZnIn2X4化合物的各种光催化应用。
ZnIn2S4has emerged as a material of interest for semiconductor-based chalcogenide photocatalysts due to its visible light absorption, chemical and thermal stability, and low cost. However, the photocatalytic activity of ZnIn2S4is affected by the limited range of visible light absorption and ultrafast recombination of solar light-induced holes and electrons. While previous studies have considered the consequences of metal doping, metal deposition, and vacancy engineering on the photocatalytic activity of ZnIn2S4, a comprehensive understanding of native point defects and how they affect electronic and photocatalytic properties remains elusive. Here, we present a density functional theory (DFT) investigation of defect energetics in ZnIn2X4(X=S, Se, Te) compounds in both bulk and ultrathin phases. Using both semi-local and hybrid DFT functionals, properties of interest such as the electronic band gap and band edges, optical absorption spectra, and carrier mobilities are first computed for defect-free structures. Although ultrathin ZnIn2S4shows lower absorption compared to other chalcogenides, it exhibits sufficient overpotential for oxidation and reduction reactions for photocatalytic water splitting. Formation energies of all possible vacancies, self-interstitials, and anti-site substitutional defects are then computed for all structures, as a function of chemical growth conditions, charge state, and Fermi level (EF), which leads to the identification of the lowest energy acceptor and donor type defects and their corresponding shallow or deep level nature. DFT results show that these metal sulfide photocatalysts are prone to ZnInand InZnanti-site substitutions, which pin the equilibrium EFclose to the conduction band edge, indicative of n-type conductivity. While ZnIndoes not create deep defect levels in ZnIn2X4, most of the stable native defects do create deep levels, which could adversely affect solar absorption. Finally, we report the influence of defects on the photocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) on ultrathin ZnIn2X4. Our results suggest that a metal interstitial defect could substantially boost HER and OER on the surface of ultrathin ZnIn2X4. Overall, this systematic first principles investigation can help drive the experimental design and defect engineering of ZnIn2X4compounds for a variety of photocatalytic applications.