Surprising Eutectics: Enhanced Properties of ZnO‐ZnWO₄ from Visible to MIR

Abstract

Zinc oxide‐zinc tungstate (ZnO‐ZnWO4 ) is a self‐organized eutectic composite consisting of parallel ZnO thin layers (lamellae) embedded in a dielectric ZnWO4 matrix. The electromagnetic behavior of composite materials is affected not only by the properties of single constituent materials but also by their reciprocal geometrical micro‐/nano‐structurization, as in the case of ZnO‐ZnWO4. The light interacting with microscopic structural features in the composite material provides new optical properties, which overcome the possibilities offered by the constituent materials. Here remarkable active and passive polarization control of this composite over various wavelength ranges are shown; these properties are based on the crystal orientation of ZnO with respect to the biaxiality of the ZnWO4 matrix. In the visible range, polarization‐dependent polarized luminescence occurs for blue light emitted by ZnO. Moreover, it is reported on the enhancement of the second harmonic generation of the composite with respect to its constituents, due to the phase matching condition. Finally, in the medium infrared spectral region, the composite behaves as a metamaterial with strong polarization dependence.

Tailoring second harmonic emission by ZnO nanostructures: Enhancement of directionality

“…We next investigate the second harmonic far-field distribution if the nanosphere were excited at 800 nm, as in the experimental set-up which we used in previous works treating materials synthetized from [19] or containing ZnO [11]. These simulations are performed using a narrow band 800 nm excitation, with the FDTD continuous wave normalization switched off, to remove the excitation pulse influence on the collection of the results at 400 nm.…”

“…With the progress of nanotechnology, micro-and nanostructuring of ZnO showed promise in efficient room-temperature nanophotonic devices based on microcavities [8] and nanowires [9]. Moreover, ZnO is non-centrosymmetric, offering efficient nonlinear optical properties at visible frequencies [10,11]. Combining welldeveloped colloidal manufacturing of ZnO [12] with electromagnetic tailoring of its nonlinear properties could open fertile field in colloidal nonlinear nanophotonics.…”

Durability of SrTiO3–TiO2 eutectic composite as a photoanode for photoelectrochemical water splitting

“…The grown rod was 120 mm long with a 3 mm diameter. The μ-PD has been demonstrated to be a useful technique for quick material growth, and has been shown to enable fabrication of materials that find applications in various fields: optoelectronics; 28,29 photonic crystals; 30–32 metamaterials; 33–36 THz materials; 37,38 and SERS detection. 39,40 X-ray powder diffraction (XRD) qualitative phase analysis of the SrTiO 3 –TiO 2 eutectic composite was performed on the as-grown samples using a Rigaku SmartLab 3 kW diffractometer.…”

Enhanced gas sensing performance of sprayed ZnO–ZnWO4 toward CO gas

“…25,26 Zinc tungstate (ZnWO 4 ) belongs to the metal tungstate family and exhibits significant potential in a range of applications, such as photoluminescence, microwave technologies, optical fibers, and environmental applications. 27,28 Numerous studies have demonstrated the efficiency of composite materials in gas sensing applications, implying that enhanced performance can be achieved by the synergistic interaction between different metal oxides. [29][30][31][32][33] In principle, mixing different semiconductor oxides can reduce their band gap, increase electron-hole pair separation, and lead to enhanced thermal dynamic stability and gas sensing activity.…”