Highly efficient green light harvesting from Mg doped ZnO nanoparticles: Structural and optical studies

Highly efficient green light emission was observed from Mg doped ZnO nanoparticles synthesized via facile wet chemical route with an average particle size similar to 15 nm. The XRD analysis confirmed the growth of wurtzite phase of ZnO nanoparticles. Moreover, the optical properties of these nanoparticles were investigated by different spectroscopic techniques. The resulted nanoparticles exhibit intense green emission peaking at 530 nm (2.34 eV) upon 325 nm (3.81 eV) excitation. The photoluminescence (PL) intensity of visible emission depends upon the doping concentration of Mg. The PL intensity was found maximum up to 4% doping of Mg, and beyond it exhibits a decrees in emission. Furthermore, by varying the band gap from 3.50 to 3.61 eV, the PL spectra showed a near band edge (NBE) emission at wavelength around 370 nm (3.35 eV) and a broad deep level emission in the visible region. The obtained highly luminescent green emission of ZnO nanoparticle would be an ultimate choice for next generation portable optoelectronics device materials

Fabrication of Artificially Stacked Ultrathin ZnS/MgF₂ Multilayer Dielectric Optical Filters

We report a design and fabrication strategy for creating an artificially stacked multilayered optical filters using a thermal evaporation technique. We have selectively chosen a zinc sulphide (ZnS) lattice for the high refractive index (<i>n</i> = 2.35) layer and a magnesium fluoride (MgF₂) lattice as the low refractive index (<i>n</i> = 1.38) layer. Furthermore, the microstructures of the ZnS/MgF₂ multilayer films are also investigated through TEM and HRTEM imaging. The fabricated filters consist of high and low refractive 7 and 13 alternating layers, which exhibit a reflectance of 89.60% and 99%, respectively. The optical microcavity achieved an average transmittance of 85.13% within the visible range. The obtained results suggest that these filters could be an exceptional choice for next-generation antireflection coatings, high-reflection mirrors, and polarized interference filters