Color-tunable luminescence, energy transfer and temperature sensing behavior of hexagonal NaYF4:Ce3+/Tb3+/Eu3+ microcrystals

Abstract

In this paper, a series of color-tunable phosphors from green to yellow and eventually to red have been successfully synthesized with efficient Ce 3+ → Tb 3+ → Eu 3+ energy transfer in hexagonal NaYF 4 host. The energy transfer processes from Ce 3+ to Tb 3+ and from Tb 3+ to Eu 3+ and the corresponding energy transfer efficiencies are carefully investigated by the photoluminescence excitation spectra, emission spectra and the decay curves. Impressively, the Ce 3+ → Tb 3+ → Eu 3+ energy transfer mechanism has been proposed and can be attributed to the strong absorption of ultraviolet light by sensitizers (Ce 3+), followed by energy migration to Tb 3+ ions, from which the energy is finally transferred to activators (Eu 3+). Furthermore, the temperature sensing behavior of β-NaYF 4 :Ce 3+ /Tb 3+ /Eu 3+ under 248 nm ultraviolet light excitation is also studied to explore the possible application of the as-synthesized sample in optical thermometry. Evidently, the results suggest that the investigated β-NaYF 4 :Ce 3+ /Tb 3+ /Eu 3+ sample may be a promising candidate for optical temperature sensor.

Synthesis and characterization of Ca3Lu(GaO)3(BO3)4:Ce3+,Tb3+ phosphors: tunable-color emissions, energy transfer, and thermal stability

“…The PLE spectrum monitored at 400 nm showed a weak excitation band peaking at 281 nm from 250–300 nm wavelength region and an intense broad excitation band peaking at 345 nm from 300–392 nm wavelength region, which were assigned to 4f–5d transition of Ce 3+ ions in CLGB:0.04Ce 3+ phosphors. 41,42 Importantly, the broad excitation band from 300 to 392 nm matched well with the emission spectra of n-UV LED chips. 43 The PL spectrum of CLGB:0.04Ce 3+ showed an asymmetric blue emission band (contain 5d → 2 F 5/2 and 5d → 2 F 7/2 transitions) from 350 to 550 nm and it could be separate into two different Gaussian peaks, peaking at 385 nm (25 974 cm −1 ) and 409 nm (24 450 cm −1 ).…”

Yb3+/Er3+ concentration dependent microstructure evolution and green/red emissions of NaYF4:Yb/Er phosphors

“…Lanthanide-doped upconversion (UC) phosphors have received considerable attention in recent years because of their unique ability to generate high energy photons under low energy photon excitations [1]. These unique anti-Stokes emitters have opened up the opportunity for applications in diverse fields such as sensors [2], solar cells [3] and fluorescent probes for bioimaging [4,5]. However, different applications have different requirements for their light emission.…”

Simultaneously tunable luminescence and magnetic properties in bifunctional NaYF4: Yb3+/Er3+ microcrystals

“…Up-conversion (UC) materials are those materials that can convert near-infrared emission into visible or ultra-violet emission. They have wide spread applications in various fields such as bio-sensors, bio-imaging, environment monitoring [1,2], information storage [3,4], anti-counterfeiting [5][6][7] and solar cells [8,9], and thus attracted a tremendous amount of attention for the past decade [10][11][12]. These trivalent lanthanide-doped ions have unique spectral and magnetic properties and a broad application prospects in many areas [13,14].…”