EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Thin films based on SiO2 and SiO2-P2O5 doped by IV-VI quantum dots were synthesized by sol-gel method, spin coating technique. The deposition process took place on glass, ITO (indium tin oxide) deposited on glass and silicon substrates, respectively. Different parameters such as precursor composition, gelation time, substrate rotation rate, number of deposited layers and pH of the precursor sols were varied in order to adjust the hydrolysis and condensation mechanisms to achieve uniform and homogeneous thin films. Different precursors for P2O5 were used such as H3PO4 and triethyl phosphate to investigate the influence on the gelation time and deposition parameters. The deposited films were heat treated for drying and subsequent annealing to promote the final oxide nanostructured materials. Structural and morphological characterization of the deposited thin films showed in evidence the nanostructured network forming role of silicon dioxide and phosphorous pentoxide. The graphically determination of the optical band gap was done in correlation with the size dependent quantum confinement effect, the latter being responsible for the optical absorption cut-off and luminescence characteristics. Optical characterization by UV-VIS-NIR spectroscopy, photoluminescence, luminescence decay and related measurements were performed. Different excitation wavelengths were used in order to select the performant materials related to photoluminescence characteristics, revealing the potential application of these nanostructured materials for temperature sensing instrumentation.