论文标题
铁弹性应变在BIVO4光吸收中的作用
Role of the ferroelastic strain in the optical absorption of BiVO4
论文作者
论文摘要
由于其在可见光光范围内非常适合的吸收边缘，其在光催化中的潜在用途最近一直在关注光催化中的潜在用途。在这里，我们表征了BIVO4单晶的光吸收是通过反射率和透射光谱的温度和极化方向的函数。发现光条间隙对温度非常敏感，并且对523K处的单斜角到四方铁弹性过渡。通过通过光平行和垂直于主轴的光吸收边缘的差异来测量的各向异性，从高温四方相中的0.2 eV降低到环境温度下的0.1 eV。我们表明，这种进化主要由铁弹性剪切应变控制。这些发现为进一步优化光催化装置中的基于二氧化摩酸酯的光吸收器提供了途径。
Bismuth vanadate (BiVO4) has recently been under focus for its potential use in photocatalysis thanks to its well-suited absorption edge in the visible light range. Here, we characterize the optical absorption of a BiVO4 single crystal as a function of temperature and polarization direction by reflectance and transmittance spectroscopy. The optical band gap is found to be very sensitive to temperature, and to the monoclinic-to-tetragonal ferroelastic transition at 523K. The anisotropy, as measured by the difference in absorption edge for light polarized parallel and perpendicular to the principal axis, is reduced from 0.2 eV in the high-temperature tetragonal phase to 0.1 eV at ambient temperature. We show that this evolution is dominantly controlled by the ferroelastic shear strain. These findings provide a route for further optimization of bismuth-vanadate-based light absorbers in photocatalytic devices.
