A novel blue-emitting Tm3+ and Tb3+ co-doped Ca9Nd(PO4)7 phosphor for white light-emitting diodes

White light-emitting diodes (WLEDs) are of paramount importance in the development of lighting and display in replace of inefficient fluorescence as well as incandescent lamps. In this work, Tb 3+ , and Tm 3+ were both introduced into a novel phosphate host Ca 9 Nd(PO 4 ) 7 . The X-ray diffraction (XRD) analyses make sure that the materials have been synthesized successfully. Further XRD Rietveld refinements were used to shed light on the site preference and the variations of crystal lattice parameters. Strong blue light emission was observed after careful optimization of the doping concentration. Theoretical computation on the basis of density functional theory checks the reliability of the phosphate host for doping luminescent centers. At last, a near-ultraviolet commercial LED chip was used with these materials to make a prototype WLED device. They possess a highly stable warm white light emission upon various driving currents (color temperature is constant 4000 K). The work has shown intriguing prospects of Ca 9 Nd(PO 4 ) 7 : Tm 3+ , Tb 3+ in lighting and display applications.