Yb 3+concentration influence on NIR and upconversion emission and temperature sensing properties of Er 3+/Yb 3+co-doped Ta 2 O 5 particles

Author(s)

Borges, Fernanda Hediger ; Mauricot, Robert ; Neumeyer, David ; de Souza, Vitor dos Santos ; Verelst, Marc ; Goncalves, Rogeria Rocha

• Document type: Journal article
• Source: Journal of Luminescence; v. 273, p. 12-pg., 2024-05-11.

Abstract

We synthesized Er 3+ and Yb 3+ co -doped tantalum oxide (Ta 2 O 5 ) spherical sub -micrometric particles by a facile method involving formation of tantalum glycolates after pouring in acetone. Then, we investigated how the annealing temperature and Yb 3+ concentration (0-30 mol %) affect their structural and luminescence properties. Particle sizes ranged from 146 to 258 nm for the samples annealed at 800 degrees C. XRD analysis revealed the orthorhombic L-Ta 2 O 5 crystalline structure. The different symmetry sites that the rare earth ions can occupy within the Ta 2 O 5 structure led to intense and broad emission bands centered around 1530 nm. Up -conversion measurements and the calculated number of photons for intense green and red emissions obtained with 980 and 1550 nm excitations helped us to elucidate the mechanisms involved at both excitation wavelengths. We investigated how the 0.5 mol % Er 3+ /1.5 mol % Yb 3+ co -doped Ta 2 O 5 sample performs as a primary thermometer by using the Boltzmann distribution law to predict the absolute temperature from the ratio between the Er 3+ 2 H 11/2 -> 4 I 15/2 and 4 S 3/2 -> 4 I 15/2 transitions. We obtained a maximum relative thermal sensitivity of 0.97 +/- 0.04 % K -1 and a minimum delta T of 2.41 K. The calculated repeatability was above 95%. These results show that promising nanothermometer based on Ta 2 O 5 with controlled size and morphology can be designed. (AU)

• FAPESP's process: 20/00277-6 - Development of nanoparticulate materials of lanthanide-doped rare earth tantalates for applications in Photonics
• Grantee: Fernanda Hediger Borges Ribeiro
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 20/05319-9 - Multifunctional plataforms based on lanthanide doped nanostructured luminescent materials for potential photonic and theranostic applications
• Grantee: Rogéria Rocha Gonçalves
• Support Opportunities: Regular Research Grants
• FAPESP's process: 23/13509-0 - Development of rare earth tantalates doped with lanthanide ions for multimodal bioimaging and nanothermometry
• Grantee: Fernanda Hediger Borges Ribeiro
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 21/08111-2 - Development of rare earth based light converters: luminescent markers, optical sensors, and amplifiers
• Grantee: Hermi Felinto de Brito
• Support Opportunities: Research Projects - Thematic Grants