Ratiometric fluorescence temperature-sensing properties of Eu3+ and Tm3+ in Gd4.67Si3O13 oxide host

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

“…120 Due to Hg 2+ -responsive ruthenium complex N719, Hg 2+ induces regular changes in the absorption spectra (absorbance is abbreviated as A) and UCL spectra, showing both ratiometric colorimetric (A 485nm /A 541nm ) and ratiometric UCL (U 541nm /U 801nm , λ ex : 980 nm) modes for naked-eye visual detection of Hg 2+ . In addition, previous studies of ratiometric UCL nanoprobe systems usually involve investigation studies of UCL lifetime, 32,36,39,47,58,60,65,72,80,86,87,93,109,116,132,134,148,161 and NIR laser pump power-dependent UCL spectral properties. 39,44,47,50,57,58,64,73 Auxiliary methods are widely used to further investigate the UCL emission behaviors of upconverting luminescence components in nanoprobe systems, aiming to yield high UCL quantum yield, bright, long-term stable, photostable, and long-lifetime UCL for sensing.…”

“…In the presence of specific targets, the emission-peak intensities of UCL 1 and UCL 2 can produce regularly and remarkably increased (↑), decreased (↓), or almost unchanged (↔) responses as the signal outputs. As clearly summarized in Tables 1-4, various types of UCL 1 /UCL 2 (abbreviated as U 1 /U 2 ) ratios have been used to form ratiometric dual-UCL outputs, extensively including 46,55,58,67,69,84 such as "increase first and then decrease of U 1 " (U 697nm ↑↓/U 789nm ↓). 58 During the construction of a functional relationship between U 1 /U 2 and the target, the common ratiometric value of U 1 /U 2 is occasionally converted into a modified form "(U 1 /U 2 ) 0 /(U 1 /U 2 )" or "(U 1 /U 2 )/ (U 1 /U 2 ) 0 ", where (U 1 /U 2 ) 0 and (U 1 /U 2 ), respectively, indicate the modified ratiometric value before and after the addition of specific targets, 147 such as "(U 487nm /U 668nm ) 0 /(U 487nm / U 668nm )".…”

“…As clearly summarized in Tables 1-4, various types of UCL 1 /UCL 2 (abbreviated as U 1 /U 2 ) ratios have been used to form ratiometric dual-UCL outputs, extensively including 46,55,58,67,69,84 such as "increase first and then decrease of U 1 " (U 697nm ↑↓/U 789nm ↓). 58 During the construction of a functional relationship between U 1 /U 2 and the target, the common ratiometric value of U 1 /U 2 is occasionally converted into a modified form "(U 1 /U 2 ) 0 /(U 1 /U 2 )" or "(U 1 /U 2 )/ (U 1 /U 2 ) 0 ", where (U 1 /U 2 ) 0 and (U 1 /U 2 ), respectively, indicate the modified ratiometric value before and after the addition of specific targets, 147 such as "(U 487nm /U 668nm ) 0 /(U 487nm / U 668nm )". 139 Of course, the so-called ratiometric UCL probe based on single UCL signal, such as the use of U 1 to construct the ratiometric signal outputs of "(U 1 ) 0 /(U 1 )", "(U 1 )/(U 1 ) 0 " or "[(U 1 ) − (U 1 ) 0 ]/(U 1 ) 0 ", where (U 1 ) 0 and (U 1 ) are U 1 peak intensi-ties without and with the targets, respectively, is not in the scope of this review.…”

“…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.…”

Luminescence thermometry based on downshifting and upconversion photoluminescence of Bi4Ti3O12:Yb3+/Pr3+ ceramic

“…Among these parameters, the utilizing of fluorescence intensity ratio can reduce the effects of unwanted fluctuations of excitation light source power on accurate measurement. Various luminescent active rare earths ions have been introduced for achieving temperature sensing based on their steady-state upconversion or downshifting photoluminescence upon appropriate wavelength excitation [8][9][10][11][12]. Trivalent praseodymium (Pr 3+ ) ions are attractive due to the green and red emissions can be generally obtained when excited by low-cost commercial blue LEDs (450 nm-470 nm) [13].…”