Morphology, structural and photoluminescence properties of shaping triple semiconductor Y_xCoO:ZrO₂ nanostructures

In the present investigation, Y_xCoO:ZrO₂ (x = 0.1, 0.3, 0.4) nanostructures (NS) are synthesized by co-precipitation and surface reduction methods using triethanol amine as surfactant and hydrazine hydrate as reducing agent. Triple-shaped semiconductor crystal features, morphology, optical absorptivity and chemical composition are determined by XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), UV–Vis and X-ray photoelectron spectroscopy. XRD patterns revealed mixed phase of tetragonal and cubic structure of Y_xCoO: ZrO₂ with less impurity peaks. SEM morphology indicates nanoparticles (NPs) of Y_xCoO:ZrO₂ spherical in nature with particle agglomerations. Average Grain size, grain boundary and interpore diameter were found to be ~ 55 nm, ~ 78 nm and ~ 115 nm, respectively. FTIR spectra of Y_xCoO:ZrO₂ (0 ≤ x ≤ 0.4) show stretching and bending peaks at ~ 533/cm (O–Y–O bond), ~ 1024/cm (Zr–O–Zr bond), broad peak at ~ 3319/cm (Y–OH) and optical absorptivity of Y_xCoO:ZrO₂ (0 ≤ x ≤ 0.4) with λ_max spread over 286 nm to 270 nm, and absorption edges appeared in between 189 and 254 nm. Chemical compositional analysis exhibited binding energies of singlet O1s at 529.8 eV, Y 3d _5/2 and Y 3d_3/2 observed at 157.8 eV and 163.9 eV, respectively, while Zr 3d_5/2 and Zr 3d_3/2 are observed at 180.4 eV and 182.7 eV. Photoluminescence spectrum (PL) of Y_xCoOZrO₂ NS exhibit peaks centred around ~ 455 nm (UV region) in case of Y_0.4Co_0.5OZr_0.1O₂ NS and for Y_0.3Co_0.5OZr_0.2O₂ NS ~ 538 nm (visible region) with various Y-, O- and Co-related native defects. Emission band was observed at UV region with ~ 415 nm to ~ 480 nm broad peak (Y_0.4Co_0.5OZr_0.1O₂ NS, λ_excitation = 380 nm) and  ~ 502 nm to ~ 582 nm in case of Y_0.3Co_0.5OZr_0.2O₂ NS with λ_excitation = 410 nm. PL emission spectra of Y_xCoO:ZrO₂ have two emission peaks centred at ~ 455 nm and ~ 538 nm with emissions bands with blue and green wavelengths. The transitions can be ascertained with shielding of 4f shells of Y⁺³ ions by 6s, 5d shells by the interaction of the other Y⁺³ ions.