Investigation on luminescence properties of BaY2Si3O10:Er3+/Ho3+–Yb3+ for optical temperature sensing

Upconversion luminescence and favorable temperature sensing performance of eulytite-type Sr3Y(PO4)3:Yb3+/Ln3+ phosphors (Ln=Ho, Er, Tm)

“…Figure 9(a) presents the temperature-dependent UC spectra of Sr 3 Y 0.88 (PO 4 ) 3 :0.10Yb 3+ ,0.02Ho 3+ under 1.00 W of 978 nm laser pumping, where it is seen that the green (543 nm; 5 Though the S A of I 801 /I 656 and I 801 /I 543 FIRs steadily increased from~0.056 × 10 −3 to 0.46 × 10 −3 K −1 and from~1.68 × 10 −3 to 9.39 × 10 −3 K −1 with the temperature increasing from 298 to 573 K (Figure 9(d)), respectively, the maximum values are yet lower than that of I 656 /I 543 FIR (~0.019 K −1 , Figure 9(b)). Accordingly, the maximum S A is~0.019 K −1 for the Sr 3 Y 0.88 (PO 4 ) 3 : 0.10Yb 3+ ,0.02Ho 3+ phosphor in the tested temperature range, which is lower than the values of K 3 Y(PO 4 ) 2 :Yb/Ho [11], BaY 2 Si 3 O 10 :Yb/Ho [16] and Ca 3 La 6 Si 6 O 24 :Yb/Ho [18] but is higher than those of Y 2 O 3 :Yb/Ho [8] and CaMoO 4 :Yb/Ho [54] (Table 1). FIR gradually decreased from~0.16% to 0.12% K −1 , those of I 801 /I 656 and I 801 /I 543 FIRs monotonically increased from~0.059% to 0.35% K −1 and from 0.19% to 0.42% K −1 , respectively.…”

“…The short fluorescence lifetime would be beneficial to temporal and spatial resolution of temperature measurement. [16][17][18], while intensity loss of the red emission is mostly due to enhanced nonradiative relaxation from the 4 F 9/2 level by intensified lattice vibration at a higher temperature. 16 The fluorescence intensity ratio (FIR) of thermally coupled 2 H 11/2 / 4 S 3/2 levels follows Boltzmann distribution, and can be described as [11,[16][17][18][19]44,52]…”

“…Optical temperature sensing with UC phosphor, most frequently investigated in the range of~293-573 K, gained increasing research interest during recent years, which utilizes the fluorescence intensity ratio (FIR) of two emission bands that involve either thermally coupled or non-thermally coupled energy levels of the luminescent ion [4,16]. The FIR technique is usually independent of spectrum loss and excitation-power fluctuation, and may thus provide a high detection resolution and excellent sensitivity [17][18][19].…”

“…The FIR of thermally coupled emission levels is a function of temperature and obeys the Boltzmann distribution of electrons [11]. Since the energy separation ΔE of such levels is usually restricted to 200-2000 cm −1 to avoid strong overlapping of two emission bands [16][17][18][19], the sensitivity of temperature sensing, which is proportional to ΔE, can hardly be further improved to a higher level according to the Boltzmann distribution. For this reason, the use of non-thermally coupled energy levels is being considered as an effective complement to a better sensitivity of FIR.…”

Na(Gd,RE)(WO4)2 double tungstates (RE=Eu/Yb-Er): crystallization from a novel layered hydroxide precursor and favorable luminescence for optical thermometry

“…At the highest measurement temperature of 548 K (275°C), the intensity of 524, 520, 530 nm drops to 67.7%, 87.9%, and 58.6% of the initial value, respectively. While the 4 right after the temperature increased and the intensity loss of the emission is mostly due to enhanced nonradiative relaxation by intensified lattice vibration at a higher temperature [8,39]. At the highest measurement temperature of 548 K (275°C), the intensity of 543, 552, 656, and 670 nm drops to 17.1%, 14.4%, 28.8%, and 26.3% of the initial value, respectively.…”