Phosphor-SiO2 composite films suitable for white laser lighting with excellent color rendering

Currently, phosphor composite films draw much attention in white laser lighting. In this work, we developed a novel phosphor-SiO2 film via a mild method, which avoiding the phosphor degradation. Commercial colloidal silica was elected as the source of SiO2 and acted as an inorganic binder, gap filler and a protective coating layer. Composite films comprised of mixed Lu3Al5O12:Ce3+ and CaAlSiN3:Eu2+ phosphors exhibit a uniform dense strucure and strong adhesion to the substrate. When excited by blue diodes laser, the optimal film exhibits excellent thermal stability (it maintains 89.1 % of the room-temperature intensity at 200 degrees C), super resistance against laser irradiation (12.9 W/mm(2)), a broad emission spectra with a full width at half maximum of 180 nm and a high luminous efficiency (183 lm/W). The color rendering index of the film was improved to 85. These outstanding properties indicate that the derived films are a promising candidate for white laser lighting.