Preparation, structure, and luminescent properties of Dy3+-doped borate Ca3La3(BO3)5: Dy3+ for potential application in UV-LEDs

A single-phase white light-emitting phosphor Ca3La3(BO3)(5): Dy3+ (CLBD) was prepared via a solid-state reaction. The introduction of Dy3+ in Ca3La3(BO3)(5) with a preferred location on La3+ was confirmed by x-ray diffraction and Rietveld structural refinement studies. The micrograph observed by scanning electron microscopy reveals an inhomogeneous and uneven dense morphology in the micrometer range. The optical spectra analysis shows that the CLBD can be efficiently excited by ultraviolet (UV) light and emitted intense white light due to the combination of blue F-4(9/2)-> H-6(15/2) (similar to 485nm) and yellow F-4(9/2)-> H-6(13/2) (similar to 575nm) emissions originated from 4f-4f transitions of Dy3+. The critical concentration is determined to be similar to 12mol.%, and the dipole-dipole (d-d) interaction is responsible for the quenching mechanism. In additional, the CLBD has high thermal stability. By incorporating the CLBD with a phosphor-capping method on AlInGaN LED, we obtain the white light that meets the spectral and efficiency requirements for high-efficacy solid-state white lighting lamps. The Commission Internationale de I'Eclairage chromaticity coordinates and color correlated temperature with optimal electroluminescence intensity are calculated to be similar to (0.338, 0.342) and 5950K, respectively. All results indicate the CLBD could serve as a promising candidate for white UV-LEDs.