title: Site-Dependent Luminescence and Thermal Stability of Eu(2+) Doped Fluorophosphate toward White LEDs for Plant Growth.
abstract: Eu(2+) activated fluorophosphate Ba3GdNa(PO4)3F (BGNPF) with blue and red double-color emitting samples were prepared via a solid-state method in a reductive atmosphere. Their crystal structure and cationic sites were identified in light of X-ray diffraction pattern Rietveld refinement. Three different Ba(2+) sites, coordinated by six O atoms referred to as Ba1, two F and five O atoms as Ba2, and two F and six O atoms as Ba3, were partially substituted by Eu(2+). Photoluminescence emission (PL) and excitation (PLE) spectra of phosphor BGNPF:Eu(2+) along with the lifetimes were characterized at the liquid helium temperature (LHT), which further confirm the existence of three Eu(2+) emitting centers resulting in 436, 480, and 640 nm emission from the 5d → 4f transitions of Eu(2+) in three different Ba(2+) crystallographic sites. These emissions overlap with the absorption spectra of carotenoids and chlorophylls from plants, which could directly promote the photosynthesis. Temperature-dependent PL spectra were used to investigate the thermal stability of phosphor, which indicates that the PL intensity of BGNPF:0.9% Eu(2+) with optimal composition at 150 °C still keeps 60% of its PL intensity at room temperature, in which blue emission has higher thermal-stability than the red emission. Furthermore, the approaching white LED devices have also been manufactured with a 365 nm n-UV LED chip and present phosphor, which make operators more comfortable than that of the plant growth purple emitting LEDs system composed of blue and red light. Results indicate that this phosphor is an attractive dual-responsive candidate phosphor in the application n-UV light-excited white LEDs for plant growth.
authors.affiliation: National Key Laboratory of Photoelectric Technology and Functional Materials in Shaanxi Province, National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Institute of Photonics & Photon-Technology and Department of Physics, Northwest University , Xi'an 710069, China.
authors.forename: Jiayu
authors.initials: J
authors.lastname: Chen
authors.affiliation: National Key Laboratory of Photoelectric Technology and Functional Materials in Shaanxi Province, National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Institute of Photonics & Photon-Technology and Department of Physics, Northwest University , Xi'an 710069, China.
authors.forename: Niumiao
authors.initials: N
authors.lastname: Zhang
authors.affiliation: National Key Laboratory of Photoelectric Technology and Functional Materials in Shaanxi Province, National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Institute of Photonics & Photon-Technology and Department of Physics, Northwest University , Xi'an 710069, China.|ARC Centre of Excellence for Nanoscale Biophotonics (CNBP), Macquarie University , North Ryde 2109, Australia.
authors.forename: Chongfeng
authors.initials: C
authors.lastname: Guo
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-Sen University , Guangzhou 510275, China.
authors.forename: Fengjuan
authors.initials: F
authors.lastname: Pan
authors.affiliation: School of Science, Chongqing University of Posts and Telecommunications , Chongqing, 400065, P. R. China.
authors.forename: Xianju
authors.initials: X
authors.lastname: Zhou
authors.affiliation: National Key Laboratory of Photoelectric Technology and Functional Materials in Shaanxi Province, National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Institute of Photonics & Photon-Technology and Department of Physics, Northwest University , Xi'an 710069, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Suo
authors.affiliation: National Key Laboratory of Photoelectric Technology and Functional Materials in Shaanxi Province, National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Institute of Photonics & Photon-Technology and Department of Physics, Northwest University , Xi'an 710069, China.
authors.forename: Xiaoqi
authors.initials: X
authors.lastname: Zhao
authors.affiliation: ARC Centre of Excellence for Nanoscale Biophotonics (CNBP), Macquarie University , North Ryde 2109, Australia.
authors.forename: Ewa M
authors.initials: EM
authors.lastname: Goldys
mesh_terms: D005063:Europium; D005459:Fluorides / Q000737:chemistry*; D049449:Luminescence; D049408:Luminescent Agents; D010710:Phosphates / Q000737:chemistry*
chemical_list: D049408:Luminescent Agents; D010710:Phosphates; C012980:fluorophosphate; D005063:Europium; D005459:Fluorides
keywords: LEDs; phosphor; plant growth; site-dependent luminescence; thermal stability