Synthesis and luminescent properties of Zn0.890Nb2O6:Eu3+0.05, Bi3+0.005, M+0.055(M = Li, Na, K) phosphors

Zn1exNb2O6:Eu3+ x , Zn0.95-yNb2O6:Eu3+ 0:05, Bi3+ y , and Zn0.890Nb2O6:Eu3+ 0:05, Bi3þ 0:005, M+ 0:055 (M ¼ Li, Na, K) redemitting phosphors were synthesized via solegel method. X-ray power diffraction, scanning electron microscopy, photoluminescence excitation, and emission spectra (PL) were used to characterize the phosphors. The obtained Zn1-xNb2O6:Eu3+ x 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 Liþ (59 pm), Naþ (99 pm), Kv (137 pm), Eu3+ (95 pm), and Zn2+ (60 pm), the emitting intensity of the phosphor increased observably by adding Liþ and Naþ as charge compensators. The PL intensity of the Kþ-doped in Zn0.945Nb2O6:Eu3+ 0:05, Bi3+ 0:005 was slightly less than those of Zn0.945Nb2O6:Eu3þ 0:05, Bi3 þ 0:005. The chromaticity coordinates of Zn0.890Nb2O6:Eu3+ 0:05, Bi3+ 0:005, Li+ 0:055 (x ¼ 0.67, y ¼ 0.34) were close to the standard of National Television Standard Committee values (x ¼ 0.670, y ¼ 0.330). The fabricated light-emitting diode (LED) further confirmed that the Zn0.890Nb2O6:Eu3+ 0:05, Bi3+ 0:005, Liþ 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.