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Abnormal Anti-Quenching and Controllable Multi-Transitions of Bi3+ Luminescence by Temperature in a Yellow-Emitting LuVO4:Bi3+ Phosphor for UV-Converted White LEDs.
- Source :
- Chemistry - A European Journal; Sep2014, Vol. 20 Issue 36, p11522-11530, 9p
- Publication Year :
- 2014
-
Abstract
- Phosphors with an efficient yellow-emitting color play a crucial role in phosphor-converted white LEDs (pc-WLEDs), but popular yellow phosphors such as YAG:Ce or Eu<superscript>2+</superscript>-doped (oxy)nitrides cannot smoothly meet this seemingly simple requirement due to their strong absorptions in the visible range. Herein, we report a novel yellow-emitting LuVO<subscript>4</subscript>:Bi<superscript>3+</superscript> phosphor that can solve this shortcoming. The emission from LuVO<subscript>4</subscript>:Bi<superscript>3+</superscript> shows a peak at 576 nm with a quantum efficiency (QE) of up to 68 %, good resistance to thermal quenching ( T<subscript>50 %</subscript>=573 K), and no severe thermal degradation after heating-cooling cycles upon UV excitation. The yellow emission, as verified by X-ray photoelectron spectra (XPS), originates from the (<superscript>3</superscript>P<subscript>0</subscript>,<superscript>3</superscript>P<subscript>1</subscript>)→<superscript>1</superscript>S<subscript>0</subscript> transitions of Bi<superscript>3+</superscript>. Increasing the temperature from 10 to 300 K produces a temperature-dependent energy-transfer process between VO<subscript>4</subscript><superscript>3−</superscript> groups and Bi<superscript>3+</superscript>, and further heating of the samples to 573 K intensifies the emission. However, it subsequently weakens, accompanied by blueshifts of the emission peaks. This abnormal anti-thermal quenching can be ascribed to temperature-dependent energy transfer from VO<subscript>4</subscript><superscript>3−</superscript> groups to Bi<superscript>3+</superscript>, a population redistribution between the excited states of <superscript>3</superscript>P<subscript>0</subscript> and <superscript>3</superscript>P<subscript>1</subscript> upon thermal stimulation, and discharge of electrons trapped in defects with a trap depth of 359 K. Device fabrication with the as-prepared phosphor LuVO<subscript>4</subscript>:Bi<superscript>3+</superscript> has proved that it can act as a good yellow phosphor for pc-WLEDs. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09476539
- Volume :
- 20
- Issue :
- 36
- Database :
- Complementary Index
- Journal :
- Chemistry - A European Journal
- Publication Type :
- Academic Journal
- Accession number :
- 97730959
- Full Text :
- https://doi.org/10.1002/chem.201402081