A 1532 nm laser-excited upconversion luminescent NaLuF4:Er microcrystals for optical thermometers

Achieving ultrasensitive temperature sensing through non-thermally coupled energy levels to overcome energy gap constraints

“…Under the sensitization of Yb 3+ ions, thermally quenched red UC emission originating from the Er 3+ : 4 F 9/2 → 4 I 15/2 transition around 660 nm and thermally enhanced near-infrared (NIR) light assigned to the Nd 3+ : 4 F 5/2 → 4 I 9/2 transition around 800 nm can be simultaneously obtained. [19][20][21] The huge difference in the temperature dependent behaviors along with the ideal emission wavelength located in the BWs makes the two NTCLs appropriate for accomplishing ultrasensitive optical thermometry in deep biological tissues. Nevertheless, as far as we know, investigations concerning temperature sensing through the NTCLs of Er 3+ and Nd 3+ ions have been seldom reported.…”

Upconversion enhancement through engineering the local crystal field in Yb3+ and Er3+ codoped BaWO4 along with excellent temperature sensing performance

“…Up to now, fluorides are the most commonly used matrixes for UC studies in the previous literature reports, especially hexagonal NaYF 4 and NaLuF 4 , which are deemed as the optimal UC hosts because of their extremely low phonon energy (∼360 cm −1 ). 3–11…”

“…Up to now, fluorides are the most commonly used matrixes for UC studies in the previous literature reports, especially hexagonal NaYF 4 and NaLuF 4 , which are deemed as the optimal UC hosts because of their extremely low phonon energy (B360 cm À1 ). [3][4][5][6][7][8][9][10][11] However, the poor chemical stability makes fluorides difficult to afford the further applications. By contrast, as an essential member of oxide family, tungstates AWO 4 (A = Ca, Sr, and Ba) with the scheelite crystal structure present remarkable optical properties along with excellent thermal and chemical stability, which makes them potential candidates for UC studies.…”