Synthesis and luminescent properties of Zn0.890Nb2O6:Eu0.053+, Bi0.0053+, M0.055+ (M = Li, Na, K) phosphors

Zn1–xNb2O6: Eu x 3 + , Zn0.95−yNb2O6: Eu 0.05 3 + , Bi y 3 + , and Zn0.890Nb2O6: Eu 0.05 3 + , Bi 0.005 3 + , M 0.055 + (M = Li, Na, K) red-emitting phosphors were synthesized via sol–gel method. X-ray power diffraction, scanning electron microscopy, photoluminescence excitation, and emission spectra (PL) were used to characterize the phosphors. The obtained Zn1−xNb2O6: Eu x 3 + phosphor showed a stronger excitation band near 400 nm. When Eu3+ and Bi3+ were incorporated into the ZnNb2O6 lattice, a broad band from 300 nm to 350 nm with the center at 329 nm appeared. Taking the ion size difference of Li+ (59 pm), Na+ (99 pm), K+ (137 pm), Eu3+ (95 pm), and Zn2+ (60 pm), the emitting intensity of the phosphor increased observably by adding Li+ and Na+ as charge compensators. The PL intensity of the K+-doped in Zn0.945Nb2O6: Eu 0.05 3 + , Bi 0.005 3 + was slightly less than those of Zn0.945Nb2O6: Eu 0.05 3 + , Bi 0.005 3 + . The chromaticity coordinates of Zn0.890Nb2O6: Eu 0 . 05 3 + , Bi 0 . 005 3 + , Li 0 . 055 + (x = 0.67, y = 0.34) were close to the standard of National Television Standard Committee values (x = 0.670, y = 0.330). The fabricated light-emitting diode (LED) further confirmed that the Zn0.890Nb2O6: Eu 0 . 05 3 + , Bi 0 . 005 3 + , Li 0 . 055 + phosphors can efficiently absorb up to 400 nm irradiation and emit red light, and are potential candidates as red-emitting components for white LED.