Boosting the Temperature Detection Accuracy of Luminescent Ratiometric Thermometry via a Multifunction Fit Strategy

Abstract

The influence of fit strategy on the temperature detection accuracy of luminescence ratiometric thermometry is investigated here. In the range of 303–783 K, the typical 2H11/2/4S3/2–4I15/2 upconversion emission lines of Er3+ embedded in calcium tungstate are investigated as a function of temperature. It is found that using the conventional one-function fit method over the whole temperature range leads to a mean error of 3.47 K. By contrast, the strategy, namely, dividing the whole board temperature range into several narrow ones and using several fit functions over separate temperature scopes, is proposed and studied. It is demonstrated that as the number of the divided temperature scopes is increased, the measured temperature readout gradually approaches to the true value of the temperature. When the number is set to be six, the temperature error sharply goes down to 0.41 K, suggesting that the newly proposed multi-function fit strategy is superior to the traditional one-function fit method, especially when a board temperature scope is involved. The reason responsible for this phenomenon is also discussed.

Ratiometric upconversion luminescence nanoprobes from construction to sensing, imaging, and phototherapeutics

“…[163][164][165] Besides, U 1 and U 2 intensities are derived from the accumulation of two UCL emissions centered at respective wavelengths, 44,69,87 such as "U 520+527nm ↑/U 540+547nm ↓". 69 Previous studies on ratiometric UCL nanoprobes probably do not provide peak wavelengths of U 1 and U 2 but indicate the related electron transitions, 31,37,38,44,60,66,69,75,80 UCL visible color changes, 39,53,93,97,98,141,161 the respective excitation wavelengths, [108][109][110]130 or the intervals of emission bands, 80,92 such as…”

“…As summarized in Table 1, previous studies have largely reported various types of ratiometric UCL nanoprobes for temperature sensing. [168][169][170][171][172][173][174][175][176]193,194 Most of the nanoprobe systems consist of lanthanide-doped UCNPs, other upconverting luminescent inorganic materials, 29,36,40,43,45,47,48,54,[56][57][58][59][60][61]65,[73][74][75][76] and the derivatives with functional modifications, including the core@shell, 37,38,41,68,72,78,79 hollow/porous, 38 complexes, 46,49,51 hybrid, 32,52 mixture, 33,35 assembly, 34,55 or engineering structures.…”

“…This review systematically summarizes various types of ratiometric UCL nanoprobes, referring to the primary structures and compositions of the nanoprobe systems, dual-signal ratiometric modes, sensing mechanisms, and application performances. For convenient mastering, previous studies on ratiometric UCL nanoprobes are appropriately classified and regularly arranged based on specific targets and characters, including temperature (Table 1), 28–84 pH (Table 2), 85–99 inorganic anions, cations, free radicals (Table 3), 100–126 gases, small common molecules, biological small molecules and biomacromolecules (Table 4). 127–162 For a better understanding of construction strategies, the following sections provide principle construction methods and ratiometric dual-signal modes of ratiometric UCL nanoprobes by discussing the state-of-the-art related studies.…”

“…Besides, U 1 and U 2 intensities are derived from the accumulation of two UCL emissions centered at respective wavelengths, 44,69,87 such as “ U 520+527nm ↑/ U 540+547nm ↓”. 69 Previous studies on ratiometric UCL nanoprobes probably do not provide peak wavelengths of U 1 and U 2 but indicate the related electron transitions, 31,37,38,44,60,66,69,75,80 UCL visible color changes, 39,53,93,97,98,141,161 the respective excitation wavelengths, 108–110,130 or the intervals of emission bands, 80,92 such as “ U 3 F 2,3 → 3 H 6 ↑/ U 1 G 4 → 3 F 4 ↓”, 38 “ U red ↑/ U green ↓”, 39 “ U ex 980nm ↔/ U ex 808nm ↓”, 108 and “ U 520–660 ↑/ U 780–820 ↔”. 92 In general, U 1 and U 2 originate from multiple up-conversion emissions of the inorganic upconverting luminescent materials.…”

“…Different types of the UCL ratiometric nanoprobes summarized in table format Ti 3 O 12 :Yb 3+ /Ho 3+ ,83 Gd 2 Mo 4 O 15 :Yb 3+ /Ho 3+ ,65 Gd 4.67 Si 3 O 13 :Eu 3+ /Yb 3+ /Tm 3+ ,58 GdVO 4 :Er 3+ ,84 Gd 2 (WO 4 ) 3 : Ho 3+ /Tm 3+ /Yb 3+ ,[73][74][75] MgMoO 4 :Er 3+ /Yb 3+ ,59 NaNbO 3 :Tm 3+ ,30 NaYF 4 :Yb 3+ /Er 3+ ,47,61,69 Y 2−x MoO 6 :xEr 3+ , 71 Y 2 O 3 :Er 3+ /Yb 3+ , 76 YVO 4 :Yb 3+ /Tm 3+ , 48 etc.…”