At present,with the increasingly serious environment and energy,the research and development of green and low energy consumption technology has attracted extensive attention. In the field of lighting, as a green light source in the 21st century,phosphor-converted White Light-Emitting Diodes(WLEDs) are expected to become an indispensable generation of comfortable and healthy lighting system due to its obvious advantages of high luminous efficiency,low environmental pollution and low energy consumption. The two key materials for commercially available WLEDs are yellow YAG:Ce phosphors and blue LED chips. In this scheme,the lack of red component results in only a low color rendering index(< 80),high related color temperature (> 4 500 K) cold white light,which are not conducive to the application of indoor lighting. Generally speaking,adding efficient red phosphors on this basis can obtain a higher color rendering index and a lower color temperature. However,one of the costs of adding such phosphors is that the device becomes significantly less efficient. From a more comprehensive and humanized perspective,the combination of ultraviolet LED chip with red,blue and green phosphors has undoubtedly attracted the attention of the majority of scientific researchers. As far as we know,rare earth ions(such as Eu2+ and Ce3+) are used as activators for most of the phosphors that can be excited by ultraviolet LED chips and tricolor phosphors in the lighting scheme. However,the mixture of three primary phosphors can easily cause spectral reabsorption. In addition, an imbalance between supply and demand makes rare earths expensive,which is a major impediment to their commercialization. In view of this situation,choosing phosphors with non- rare earth ions as activators can effectively solve the above problems of rare earth doped phosphors. Nowadays,as another type of activator,bismuth(Bi),has been extensively studied and reported because of the potential optical properties related to the strong interaction with surrounding coordination environments and abundant valence states. In this paper,a series of BaLa1-xGa3O7:xBi(3+)(0.01 <= x <= 0.13)phosphors were synthesized through traditionnal high temperature solid state method. The Xray diffraction patterns and rietveld refinement results indicate the pyrite structure of above samples. Scanning electron microscope images show that the phosphor particles are irregular in shape with the size of 5 similar to 30 mu m. Diffuse reflectance spectra of BaLaGa3O7 matrix indicate a suitable optical band gap for Bi3+ luminescence. When Bi3+ substitutes La3+,the excitation wavelength has a red shift from 340 to 350 nm. Under the excitation of 348 nm ultraviolet light, BaLa1-xGa3O7:xBi(3+) phosphors exhibit one evident emission peak at 475 nm. With the increase of Bi3+ concentration,the emission intensity firstly increased and then decreased,and this optical phenomenon is generally considered to be related to the concentration quenching. Among them, the emission intensity of BaLa0.89Ga3O7:0.11Bi3+ phosphor reaches the maximum with a quantum yield of 19.2%,and the emission intensity at 150. still maintains 69.2% of that at 25.. It indicates that the BaLa1-xGa3O7:xBi(3+) phosphors have potential application value in the field of near ultraviolet excitied white LEDs.
