title: Self-assembled peanut-like Ln3+ (Ln = Tb, Sm, Eu) doped NaLa(WO4)2: phase control and its relevance to luminescence modification.
abstract: Ln3+ (Ln = Tb, Sm, Eu) doped NaLa(WO4)2 peanuts were successfully self-assembled by a facile EDTA assisted hydrothermal treatment. EDTA played critical roles in the phase and morphology control, which regulated the phase transformation from monoclinic La2(WO4)3 flowers to tetrahedral NaLa(WO4)2 peanuts. La2(WO4)3:Tb3+ exhibited two broad excitation bands at 280 and 340 nm, which are related to the normal and perturb sites of WO4(2-). However, the excitation band for NaLa(WO4)2:Tb3+ shifted to near ultraviolet region and showed only one broad excitation band originating from perturb sites. Under ultraviolet excitation, La2(WO4)3:Tb3+ displayed green light and NaLa(WO4)2:Tb3+ showed blue-green light consisting of WO4(2-) self-activated blue emission and the characteristic Tb3+ emission. It can be clearly seen that the blue emission of WO4(2-) was not sufficiently quenched in NaLa(WO4)2 as that in La2(WO4)3, because the distortions of crystalline lattice for NaLa(WO4)2 may alter the energy migration processes. When doping with Sm3+ and Eu3+, NaLa(WO4)2 peanuts exhibited white color emission which may find practical applications in solid state lighting devices.
authors.affiliation: College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, Inner Mongolia 010021, P. R. China.
authors.forename: Yiguo
authors.initials: Y
authors.lastname: Su
authors.forename: Chunfang
authors.initials: C
authors.lastname: Du
authors.forename: Qingyue
authors.initials: Q
authors.lastname: Jia
authors.forename: Li
authors.initials: L
authors.lastname: Lv
authors.forename: Qinglong
authors.initials: Q
authors.lastname: Liu
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Wang