TiO2 films obtained by the sol-gel process and doped with Yb3+ and Er3+ ions

Author(s)

Baldini, Danielle C. ^[1] ; de Faria, Emerson H. ^[1] ; Ciuffi, Katia J. ^[1] ; Rocha, Lucas A. ^[1] ; Nassar, Eduardo Jose ^[1]

Affiliation

^[1] Univ Franca, Ave Dr Armando Salles Oliveira, 201 Pq Univ, BR-14404600 Franca, SP - Brazil

• Document type: Journal article
• Source: Journal of Sol-Gel Science and Technology; v. 97, n. 3 JAN 2021.
• Web of Science Citations: 0

Abstract

The upconversion mechanism based on lanthanide ions has been studied in several systems and has been applied in various fields, such as sensors, biological markers, and photovoltaic cells. This work investigates the properties of the lanthanides Er3+ and Yb3+ doped into titanium oxide at different molar concentrations. The sol-gel methodology and the spin-coating technique were used to prepare the thin films. To promote the upward energy conversion mechanism, the materials were submitted to thermal treatment at 500 degrees C after the depositions. Before and after thermal treatment, the films presented 80% and 83% optical transparency above 350 nm, respectively. The X-ray diffractograms of all the films attested to the beginning of TiO2 crystallization, as evidenced by the characteristic peak of the titania phase (JCPDS \# 23-1446). The emission spectra of the films excited at 980 nm exhibited the characteristic Er3+ emission bands in the green (525 and 555 nm) and red (660 nm) regions, which corresponded to the H-4(11/2)/S-4(3/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2) transitions, respectively. On the basis of the emission intensity as a function of laser power, two photons were involved in the process. The Fluorescence Intensity Ratio (FIR) indicated a rise in the local temperature, which was induced by excitation light, or the laser power. {[}GRAPHICS] (AU)

• FAPESP's process: 15/20298-0 - Obtention of luminescent LaNbO4:Ln (ln = Dy, TM, er and Yb) matrices prepared by spray pyrolysis process
• Grantee: Lucas Alonso Rocha
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/02641-0 - 6th Nano Today Conference
• Grantee: Eduardo José Nassar
• Support Opportunities: Research Grants - Meeting - Abroad