Ultraviolet upconversion fluorescence from ^6D_J of Gd^3+ induced by 980 nm excitation

Abstract

Ultraviolet upconversion emissions of 246.2 and 252.8 nm from (6)D(J) levels of Gd(3+) ions were observed in GdF(3): 10% Yb(3+), 0.7% Tm(3+) nanocrystals under 980 nm excitation from a laser diode. The (6)D(J) levels of Gd(3+) ions can be efficiently populated by energy transfer processes of Yb-->Tm-->Gd and Yb-->Gd. A six-photon upconversion process was confirmed by the dependence of 252.8 nm emission intensity on the pumping power. The upconversion mechanism in the six-photon process was discussed based on excited state absorption of Gd(3+) ions, cross relaxation energy transfer between two excited Gd(3+) ions, and energy transfer between Gd(3+) and Yb(3+) or Tm(3+) ions.

Sensitized high-order ultraviolet upconversion emissions of Gd3+ by Er3+ in NaYF4 microcrystals

“…In addition, unlike Er 3+ , Tm 3+ , and Ho 3+ ions, UC emissions based on Gd 3+ ions have rarely been reported. As far as we know, there were only four papers reported by Gharavi [13,[17][18][19]. The first author found 281 and 313 nm UC emissions from 6 I J and 6 P J levels of Gd 3+ , respectively.…”

Spectroscopic properties Eu3+ doped and Tm3+/Yb3+ codoped oxyfluoride glass ceramics containing Ba2GdF7 nanocrystals

“…3 H 6 in NaYF 4 [15] and YF 3 [18] nanocrystals. Thus, the energy was mainly transferred to 6 I J level of Gd 3+ ions, as the case in the Tm 3+ /Yb 3+ codoped GdF 3 system [19]. In a Tm 3+ -Yb 3+ -Gd 3+ codoped system, the excited states 6 I J of Gd 3+ can be populated through the energy transfer 3 P 2 !…”

Ultraviolet and blue up-conversion fluorescence of NaY0.793−xTm0.007Yb0.2GdxF4 phosphors

“…The intensity is magnified 5 times in the wavelength range of 240-270 nm for the fluorescence is relatively weak. The emissions which peaked at 246.4 and 252.8 nm are assigned to transitions from 6 D 7/2 , 6 D 9/2 → 8 S 7/2 of Gd 3+ , respectively [12]. The emission that centered at 264.6 nm comes from 3 P 2 → 3 H 6 transition of Tm 3+ .…”

“…As reported in Ref. [12], three mechanisms should be considered in populating the 6 D J levels, viz. excited state absorption (ESA), CRET, and ET.…”

“…Cao et al reported the 6 I J and 6 P J states to the ground state 8 S 7/2 emissions of Gd 3+ in YF 3 with a 980-nm LD as excitation source in 2008 [11]. Later, Qin et al observed the 6 D J levels to the 8 S 7/2 level emissions in GdF 3 under the same measurement conditions [12]. Subsequently, Chen et al reported the near vacuum UV (VUV) UC fluorescence of Gd 3+ in NaGdF 4 powders under a 974-nm LD excitation [13].…”