Improved optical properties of Dy3+ doped phosphors by spherical SiO2 particles

Abstract

In this research YVO4:Dy 3+ luminescent material was synthesized via a facile and one-step solid state method at 1100 °C. Then the effects of spherical and irregular SiO2 particles on microstructure and photoluminescence properties of the phosphors were investigated in details. To study about the microstructure and characteristics of these composites, XRD, SEM, TEM, HRTEM, XPS and PL equipment were employed. The XPS results proved that via the addition of SiO2, strong bonding is produced between SiO2 particles and YVO4:Dy3+ phosphors and based on the stronger electronegativity of Si 2p compared to Y 3d and V 2p elements, the increase of binding energy has occurred. Moreover, this research showed that the addition of 7 wt% spherical SiO2 particles provides strongest excitation and emission luminescence properties. Interestingly, further increase of SiO2 results in the suppression of emission intensity. Also, it was found that the emission intensities of the phosphors including SiO2 spheres are significantly stronger than the phosphors consisting irregular shape SiO2 which can be interpreted by the light scattering phenomenon. Via finite difference time domain (FDTD) simulation, it was revealed that the scattering cross section of the phosphors consisting spherical SiO2 is significantly smaller than that of the phosphors consisting irregular SiO2. In addition, the reflection of the former is less than that of the latter since SiO2 spheres cover more empty spaces among YVO4 particles.