title: Energy transfer between Ce³⁺  → Gd³⁺ or Tb³⁺ in KNaSO₄ microphosphor.
abstract: KNaSO4 microphosphor doped with Ce,Gd and Ce,Tb and prepared by a wet chemical method was studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) characterization. KNaSO4 has a 5-µm particle size detected by SEM. KNaSO4:Ce(3+),Tb(3+) showed blue and green emission (at 494 nm, 557 nm, 590 nm) of Tb(3+) due to (5)D(4)  → (7)F(J) (J = 4, 5, 6) transitions. KNaSO4:Ce(3+),Gd(3+) showed luminescence in the ultraviolet (UV) light region at 314 nm for an excitation at 271 nm wavelength. It was observed that efficient energy transfer took place from Ce(3+)  → Gd(3+) and Ce(3+)  → Tb(3+) sublattices indicating that Ce(3+) could effectively sensitize Gd(3+) or Tb(3+) (green emission). Ce(3+) emission weakened and Gd(3+) or Tb(3+) enhanced the emission significantly in KNaSO4. This paper discusses the development and understanding of photoluminescence and the effect of Tb(3+) and Gd(3+) on KNaSO4:Ce(3+).
authors.affiliation: Department of Physics, Sardar Patel Mahavidyalaya, Chandrapur, 442402, India.
authors.forename: Urvashi
authors.initials: U
authors.lastname: Manik
authors.affiliation: Department of Physics, K.Z.S. Science College, Kalmeshwar, Nagpur, 441501, India.
authors.forename: S C
authors.initials: SC
authors.lastname: Gedam
authors.affiliation: Department of Physics, R.T.M. Nagpur University, Nagpur, 440033, India.
authors.forename: S J
authors.initials: SJ
authors.lastname: Dhoble
mesh_terms: D002563:Cerium / Q000737:chemistry*; D004735:Energy Transfer; D005682:Gadolinium / Q000737:chemistry*; D049449:Luminescence; D011188:Potassium / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D013725:Terbium / Q000737:chemistry*
chemical_list: D013431:Sulfates; D013725:Terbium; D002563:Cerium; D012964:Sodium; D005682:Gadolinium; D011188:Potassium
keywords: energy transfer; luminescence; phosphor; sensitizer and activator; spectroscopy; wet chemical method