Phase-sensitive radioluminescence and photoluminescence features in Tm3+-doped yttrium tantalates for cyan and white light generation

Author(s)

Labaki, Hayra do Prado ; Caixeta, Fabio Jose ; Marques, Natasha Policei ; Jose Guidelli, Eder ; Rocha Goncalves, Rogeria

• Document type: Journal article
• Source: DALTON TRANSACTIONS; v. 51, n. 29, p. 17-pg., 2022-06-24.

Abstract

Radioluminescence and visible photoluminescence tunability features from a single Tm3+-doped yttrium tantalate phosphor prepared by a soft sol-gel method designed to afford cubic Y3TaO7 and monoclinic M '-YTaO4 crystalline phases are reported. The annealing temperature influenced the crystallization kinetics and stabilized a preferential phase. To investigate how the crystalline phase affected the Tm3+ optical properties, excitation and emission spectra in the visible range were recorded for the samples annealed at 900 or 1100 degrees C. Inhomogeneous broadening in the emission spectra was due to the structural disorder of the Y3TaO7 phase. Energy transfer between the yttrium tantalate host and Tm3+ ions was observed upon CT band excitation. Under UV light, an intense and tunable cyan to blue emission ascribed to both the Tm3+ transitions D-1(2) -> F-3(4) and (1)G(4) -> H-3(6) also emerged and could be observed by the naked eye. The lifetime decay curves demonstrated the occupation of distinct sites and that the symmetry sites occupied by Tm3+ ions in the Y3TaO7 host have higher lifetime values than in the M '-YTaO4 phase. A radioluminescence study was carried out to evaluate the yttrium tantalate scintillation performance, which was considerably enhanced in the presence of the M '-YTaO4 phase. Intense white light emission displaying a large color correlated temperature range could be obtained by controlling the delay time for the time-resolved measurements and upon an orange-emitting phosphor addition. All the above-mentioned structural and photoluminescence properties make these Tm3+-doped yttrium tantalates potential candidates for photonic applications, particularly integrated w-LED systems. (AU)

• FAPESP's process: 17/10423-7 - Broad band NIR emission from nanostructured Rare earth doped Nb2O5 and Ta2O5 derived materials for photonic applications as optical amplifiers and energy converters.
• Grantee: Fábio José Caixeta
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 19/25991-6 - Study of upconversion processes in nanostructured materials based on rare earth doped GeO2-Ta2O5 with high emission quantum yield
• Grantee: Fábio José Caixeta
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate