Enhanced Tm3+ blue emission in Tm, Yb, co-doped fluorophosphate glasses due to back energy transfer processes

Abstract

Up-conversion emission spectra of fluorophosphate glasses doped with Tm3+ and co-doped with Tm3+ and Yb3+ ions were obtained under two different excitation wavelengths (657 and 683 nm). Both samples show a stronger emission centered at 450 nm than the ones centered at 478 and 363 nm when 3F2 level of Tm3+ is excited at 657 nm. If 3F3 level of Tm3+ is excited with the 683 nm light the 478 nm emission of the double doped sample becomes much stronger (about 200 times) than the same emission of the single doped sample. We propose an up-conversion mechanism to explain the spectra which is in agreement with quadratic dependence of the emission intensities on the excitation power under both excitations.

Red to UV and blue up-conversion in alumina sol containing only Tm 3+ or both Tm 3+ and Yb 3+ ions via low energy pumping

“…Therefore, the blue up-conversion emissions corresponding to 1 D 2 e 3 F 4 and 1 I 6 e 3 H 4 transitions are weakened. The population of 3 F 4 level is affected by the following processes as Yb 3þ ion exist: ① The back energy transfer process: 2 F 5/2 (Yb 3þ ion) e 3 H 5 (Tm 3þ ion) increases the 3 H 5 level population, and then increases the 3 F 4 level population by the nonradiative relaxation from 3 H 5 level to 3 F 4 level [33]; ② The 3 F 4 population decreases for the cross relaxations: 1 D 2 e 3 F 4~3 H 4 e 1 I 6 and 3 H 4 e 3 F 4~3 H 6 e 3 F 4 are weakened by energy transfer from Tm 3þ ion to Yb 3þ ion. In general, the population of 3 F 4 level is less sensitive to Yb 3þ ion concentration compared to that of 3 H 4 level.…”

Tunable and white light generation in lanthanide doped novel fluorophosphate glasses

“…The Judd-Ofelt analysis has been carried out and it is concluded that glasses containing NaF have stronger optical intensities. The upconversion emission of Tm 3+ /Yb 3+ ions co-doped fluorophosphate glasses is also investigated and a strong emission line at 480 nm is observed [77]. It is concluded that the addition of Yb 3+ ions to the singly doped Tm 3+ glasses increases the upconversion intensity up to 200 times.…”

Multicolor (Vis-NIR) mesoporous silica nanospheres linked with lanthanide complexes using 2-(5-bromothiophen)imidazo[4,5-f][1,10]phenanthroline for in vitro bioimaging

“…26 The Yb 3+ ion can also transfer energy to other lanthanide ions, such as Ho 3+ ions, 50 Er 3+ ions, 51 and Tm 3+ ions. 52 Furthermore, the NIR emission band (around 980 nm) of Yb-Tip-MSS under the visible excitation is located in the biological transparent window (700-1000 nm), 9 and the emissive (around 1000 nm, see Fig. S6 †) protein conjugate has been applied in medical diagnostics.…”