Saroar Shahad, Sultana Shadmin, Nishat Sadiq Shahriyar, Hossain Quazi Shafayat, Khan M N I, Islam Dipa, Akhtar Umme Sarmeen, Shahriar Bashar Muhammad, Jahan Sharmin, Hossain Khandker Saadat, Ahmed Imtiaz
Materials Science Research Laboratory, Department of Electrical and Electronic Engineering, University of Dhaka, Dhaka 1000, Bangladesh.
Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States.
ACS Omega. 2024 Aug 14;9(34):36314-36325. doi: 10.1021/acsomega.4c03171. eCollection 2024 Aug 27.
The wide band gap γ-BiMoO (BMO) has tremendous potential in emergent solar harvesting applications. Here we present a combined experimental-first-principles density functional theory (DFT) approach to probe physical properties relevant to the light sensitivity of BMO like dynamic and structural stability, Raman and infrared absorption modes, value and nature of band gap (i.e., direct or indirect), dielectric constant, and optical absorption, etc. We solvothermally synthesized wide band gap 2 phase pure BMO (≳3 eV) for two different pH values of 7 and 9. The structural parameters were correlated with the stability of BMO derived from elastic tensor simulations. The desired dynamical stability at = 0 K was established from the phonon vibrational band structure using a finite difference-based supercell approach. The DFT-based Raman modes and phonon density of states (DOS) reliably reproduced the experimental Raman and infrared absorption. The electronic DOS calculated from Heyd-Scuseria-Ernzerhof HSE06 with van der Waals (vdW) and relativistic spin-orbit coupling (SOC) corrections produced a good agreement with the band gap obtained from diffuse reflectance spectroscopy (DRS). The optical absorption obtained from the complex dielectric constant for the HSE06+SOC+vdW potential closely resembled the DRS-derived absorption of BMO. The BMO shows ∼43% photocatalytic efficiency in degrading methylene blue dye under 75 min optical illumination. This combined DFT-experimental approach may provide a better understanding of the properties of BMO relevant to solar harvesting applications.
宽带隙γ-铋钼酸盐（BMO）在新兴的太阳能收集应用中具有巨大潜力。在此，我们提出一种结合实验与第一性原理密度泛函理论（DFT）的方法，以探究与BMO光敏感性相关的物理性质，如动态和结构稳定性、拉曼和红外吸收模式、带隙值及性质（即直接或间接带隙）、介电常数和光吸收等。我们采用溶剂热法在两种不同pH值（7和9）下合成了宽带隙2相纯BMO（≳3 eV）。通过弹性张量模拟得出的结构参数与BMO的稳定性相关。利用基于有限差分的超胞方法，从声子振动能带结构确定了在T = 0 K时所需的动态稳定性。基于DFT的拉曼模式和声子态密度（DOS）可靠地再现了实验拉曼和红外吸收。通过含范德华（vdW）和相对论自旋轨道耦合（SOC）修正的Heyd-Scuseria-Ernzerhof HSE06计算得到的电子DOS与漫反射光谱（DRS）获得的带隙吻合良好。对于HSE06 + SOC + vdW势，从复介电常数得到的光吸收与DRS得出的BMO吸收非常相似。在75分钟光照下，BMO在降解亚甲基蓝染料方面显示出约43%的光催化效率。这种结合DFT的实验方法可能有助于更好地理解与太阳能收集应用相关的BMO性质。
