Currently, white light-emitting diodes (WLEDs) have drawn worldwide attention because of the compactness, high efficiency, good stability in physical and chemical properties, long operational lifetime, as well as energy saving and environmental protection.1,2 WLEDs are widely used in the field of lighting and backlit lamps.
3,4 Moreover, the enormous progress made in the commercial LED chips with the near-UV light ranging from 350 to 420 nm has greatly boosted the research interest in phosphors excited efficiently within this range.
Nowadays, the most prevalent way of fabricating WLEDs is to combine yellow-emission Y3Al5O12:Ce3+ phosphors with commercial blue LED chips.
5 The characters of the simple combination have been shown by Jang et al.6 Obviously, there
exists a notable deficiency based on the tricolor theory.
The drawback in red spectral region restricts the range of their application in several significant practical fields, especially as alternatives for the fields with lower color temperatures that dominate the lighting markets.
In order to match well with the color requirements of lighting fields, novel red-emitting
phosphors have been synthesized to improve the properties of the color temperatures and color rendering index (CRI).
These near-UV light excited red-emitting phosphors are synthesized on the basis of Eu3+-activated host, such as CaYAl3O7:Eu3+7 and La2O2S:Eu3+.8 Whereas some defects for