Red, green, blue and white light upconversion emission in Yb³⁺/Tm³⁺/Ho³⁺ co-doped tellurite glasses

Abstract

Several Yb3+/Tm3+/Ho3+ co-doped transparent TeO2–ZnO–Na2O–Yb2O3–Ho2O3–Tm2O3 glasses were prepared and luminescence properties were characterized. Simultaneous red, green and blue (RGB) emission were obtained after excitation at 970 nm. Colour emission was tuned from multicolour to white light with colour coordinate (0.32, 0.33) matching very well with the white reference (0.33, 0.33). Changes in colour emission were obtained by varying the intensity ratios between RGB bands that are strongly concentration dependent because of the interaction of co-dopants. The colour tunability, high quality of white light and high intensity of the emitted signal make these transparent glasses excellent candidates for applications in solid-state lighting.

Nanoparticulate Coatings with Efficient Up-Conversion Properties

“…YVO 4 :Yb,Er powders in KBr pellets were excited at 975 nm using a 1 W laser diode (L975P1WJ Thorlabs) and their UC emission was detected with an Ocean Optics spectrometer (QE 65 000). To compare the efficiency of the different samples, green and red emissions were integrated between 500 and 600 nm and 600 and 700 nm, respectively, and normalized in acquisition time.…”

Switching green to red emission in tridoped ZrO2:Yb3+–Er3+–Bi3+ nanocrystals

“…For example, in the case of UC process, Yb 3+ is a well-known sensitizer ion for Er 3+ , Ho 3+ , Tm 3+ , and Pr 3+ , which makes it possible to obtain strong emissions while in its absence it is impossible [4,[14][15][16]. In addition, it has been reported that the use of Li 2+ and Gd 3+ enhances the visible emission from Eu 3+ and Er 3+ , respectively.…”

Upconversion white luminescence of TeO2:Tm3+/Er3+/Yb3+ nanoparticles

“…Sources of white light has been wide studied since it find applications in many fields, such as three dimensional displays, long lifetime, low-energy light sources, back light and so on [1][2][3][4][5][6][7][8][9][10][11]. One of the effective ways of generating white light is the upconversion in which near-infrared excitation is converted into a visible emission through lanthanide doping.…”

“…The excitation source of upconversion is an infrared laser, which is compact, power-rich, inexpensive, and can be commercially available. Up to now, there have been several reports on upconversion white luminescence from Tm 3+ /Er 3+ /Yb 3+ or Tm 3+ /Ho 3+ /Yb 3+ doped glasses/powders/ceramic/nanocrystals, such as tellurite glasses [9,10], Y 2 O 3 nanocrystals [11], Y 2 O 3 transparent ceramic [12], Lu 2 O 3 nanocrystals [13], GdVO 4 nanocrystals [14], KY 3 F 10 nanocrystals [4], CaSnO 3 powders [15], Gd 4 O 3 F 6 nanocrystals [16], NaYF 4 nanorods [17] and fluoride glasses [18,19]. For example, Zhang's group studied color control and white light generation of upconversion luminescence by operating dopant concentrations and pump densities in Tm 3+ /Er 3+ /Yb 3+ tri-doped Lu 2 O 3 nanocrystals [13].…”

“…It is well known that TeO 2 (optical fibers, crystals and glassy) are suitable host materials due to their lower phonon frequency, chemical durability and thermal stability [20][21][22][23][24][25][26][27][28][29]. The conventional processing is using bulk TeO 2 or TeO 2 glasses as the host materials for preparing upconversion luminescent materials [9,30,31] [31]. Nanoscale upconversion luminescent materials prepared using nanoparticles as the host materials have attracted much interest because their optical properties, such as lifetime improvement and spectral stability, are different from those of the bulk samples.…”