White light generation from Dy3+-doped ZnO–B2O3–P2O5 glasses

Abstract

Dysprosium doped ZnO–B2O3–P2O5 (ZBP) glasses were prepared by a conventional melt quenching technique in order to study the luminescent properties and their utility for white light emitting diodes (LEDs). X-ray diffraction spectra revealed the amorphous nature of the glass sample. The present glasses were characterized by infrared and Raman spectra to evaluate the vibrational features of the samples. The emission and excitation spectra were reported for the ZBP glasses. Strong blue (484 nm) and yellow (574 nm) emission bands were observed upon various excitations. These two emissions correspond to the F49/2→H615/2 and F49/2→H613/2 transitions of Dy3+ ions, respectively. Combination of these blue and yellow bands gives white light to the naked eye. First time, it was found that ZnO–B2O3–P2O5 glasses efficiently emit white light under 400 and 454 nm excitations, which are nearly match with the emissions of commercial GaN blue LEDs and InGaN LED, respectively. CIE chromaticity coordinates also calculated for Dy3+: ZBP glasses to evaluate the white light emission.

New Single-Phase, White-Light-Emitting Phosphors Based on δ-Gd2Si2O7 for Solid-State Lighting

“…32 The CCT values, calculated using the empiric formula given by McCamy 23 were 7077 K, 7111 K, and 6721 K for the 0.5, 1.0 and 2% Dy doped samples, respectively. This temperature is some 1000 K higher than the highest CCT reported in the literature for Dy 3+ -based phosphors, 33,34,35 which makes this phosphor very useful for inside illumination of offices, classrooms, etc., where a cold lighting (higher CCT) is used to enhance concentration. In order to synthesize a single-phase phosphor, which emits white light with broad spectral dispersion, we have codoped the δ- and Eu 3+ at 273 nm, as well as to the low concentration of Tb, which allows observation of the blue emission, as explained above.…”

“…30, y=0. 33 and CCT values between 7077 K and 6721 K. The decay curves of the main transitions of Dy 3+ showed a maximum lifetime value for δ-Gd 2 Si 2 O 7 :0.5%Dy, which is, therefore, the most efficient doping level. Secondly, a broad spectral range, single-phase, WL-emitting phosphor was generated by co-doping δ-Gd 2 Si 2 O 7 with Tb Keywords: rare earth silicates, luminescence, LEDs, energy transfer…”

Photoluminescence properties of LiBaPO4:M3+ phosphor for near‐UV light‐emitting diode (M = Eu and Dy)

“…The yellow-to-blue ratio, known as the asymmetry ratio of the Dy 3+ ion, varies while locating in different host lattices (14). In LiBaPO 4 :Dy 3+ , predominant emission is around 574 nm, which suggests that the ligand field is towards its inversion symmetry.…”

“…Thus, the several Dy 3+ -doped phosphors have been studied to obtain two primary color luminescent materials as well as white-light-emitting material (12,13). The intensities of hypersensitive ( 4 F 9/2 → 6 H 13/2 ) and non-hypersensitive ( 4 F 9/2 → 6 H 15/2 ) transitions depend on the coordination environment of the host material and the yellow-to-blue luminescence intensity ratio (Y/B), which can be modulated by varying the composition of host matrix and heat treatment for the generation of white light (14). The blue and yellow color light emissions can produce white light through an appropriate combination of Dy 3+ -doped materials.…”

Luminescence properties of Dy3+ doped zinc–aluminum–sodium–phosphate (ZANP) glasses for white light applications

“…The band at ~735 cm -1 is attributed to the symmetric stretching vibrations of P-O-P rings [18]. The band at 899 cm -1 is owing to asymmetric stretching vibrations of P-O-P groups linked with linear meta phosphate chain [19,20]. At ~1103 cm -1 , the spectrum consists of a band, which is due to asymmetric stretching of PO 2 -group, υ as (PO 2 -) modes [14,15].…”