Structure, Morphology and Upconversion Luminescence of Rare Earth Ions Doped LiY₉(SiO₄)₆O₂ for Temperature Sensing

Abstract

To develop novel upconversion (UC) luminescence materials for optical temperature sensing applications, the rare earth (Yb3+, Er3+, Ho3+, and Tm3+) ions doped LiY9(SiO4)6O2 phosphors were developed. The single-phase samples were confirmed by XRD patterns. The morphology characteristics were studied via SEM and TEM techniques. When excited by 980 nm, the optimal doping concentrations for Er3+/Ho3+/Tm3+ were determined in the UC emission spectra and their characteristic emission peaks were attributed. The temperature-dependence of the UC spectra was investigated by using different strategies. The maximum absolute sensitivities were calculated to be 4.77 × 10–3 K–1 for I522/I548 (Er3+), 0.034 K–1 for I661/I522 (Er3+), 0.034 K–1 for I660/I548 (Ho3+), and 2.74 × 10–4 K–1 for I695/I789 (Tm3+), which show high sensitivity values. Among these activator ions, the Tm3+ activated sample demonstrates the largest relative sensitivity. Compared with some previous lanthanide ions activated temperature-sensing luminescence materials, the present phosphors exhibit improved sensitivities and could show potential applications for temperature sensors.

Synthesis and Upconversion Luminescence of LiY9(SiO4)6O2 Phosphor Doped with Pr3+

“…In this work, the results of investigations of apatite-type silicate LiY 9 (SiO 4 ) 6 O 2 :Pr 3+ are present. Recently, LiY 9 (SiO 4 ) 6 O 2 activated by Ce 3+ , Eu 3+ , Yb 3+ , Er 3+ , Ho 3+ , and Tm 3+ has garnered significant attention due to its excellent luminescent characteristics. − Among its various applications, LiY 9 (SiO 4 ) 6 O 2 :Eu 3+ phosphor shows great promise in the field of white light-emitting diodes . In addition, LiY 9 (SiO 4 ) 6 O 2 doped with Dy 3+ and Ce 3+ has been established as an efficient luminescent ratiometric thermometer .…”

High-Gravity-Assisted Intensified Preparation of Er-Doped and Yb/Er-Codoped CaF2 Upconversion Nanophosphors for Noncontact Temperature Measurement

“…Rare earth doped upconversion (UC) luminescent nanoparticles (NPs) have sparked considerable interest for their large range of applications, especially in noncontact optical temperature measurements. − Based on the fluorescence intensity ratio (FIR) technique, optical temperature sensing is regarded as the most promising thermal-sensing method owing to its high thermal resolution, increased sensitivity, noninvasive operation, and reduced measurement conditions dependence. − This technique is implemented by measuring the photoluminescence intensities from two thermally coupled energy levels (TCLs), of which the energy gap (Δ E ) should be larger than 200 cm –1 but lower than 2000 cm –1 . , The TCLs are provided by the rare earth ions, among which Er 3+ is often selected for noncontact thermometry application owing to its TCLs of 2 H 11/2 and 4 S 3/2 because the Δ E between them is normally 500–800 cm –1 . , This avoids strong overlapping of the two emission bands. , Usually, Yb 3+ is combined and used as a sensitizer because of the large absorption cross section around 980 nm wavelength and efficient energy transfer to Er 3+ . , Besides the rare earth ions, the host matrixes are also crucial parts of the UC luminescent nanophosphors …”

The thermo-optic relevance of Ho3+in fluoride microcrystals embedded in electrospun fibers

“…[3][4][5][6][7] A suitable choice for non-contact temperature measurement is the temperature measurement feedback method based on the uorescence intensity ratio (FIR), which avoids spectral loss and excitation source uctuation, and its sensitivity and accuracy are higher than traditional ways of measuring temperature. [8][9][10][11][12][13][14][15] Rare Earth (RE) ion doped materials are widely applied in non-contact temperature control measurement because their thermal coupling energy levels respond to changes in laser power and temperature. [16][17][18][19][20][21][22][23] By measuring the uorescence intensity ratio of the thermal coupling energy levels of the RE doped materials, the temperature changes around the uorescent probe can be monitored.…”