title: Infrared to infrared upconversion emission in Pr(3+)/Yb(3+) co-doped La2O3 and La(OH)3 nano-phosphors: a comparative study.
abstract: The Pr(3+)/Yb(3+) co-doped La2O3 and La(OH)3 nano-phosphors have been synthesized through solution combustion method. The structure and morphology of the samples have been studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The physical and optical properties of the samples have been measured and compared. A broad intense infrared emission centered at 850nm due to (1)I6→(1)G4 transition along with sharp green emission centerd at 513nm due to (3)P0→(3)H4 transition are observed on excitation with 976nm laser. The emission intensity of Pr(3+) is optimized with concentration and it is maximum at 0.08mol%. The annealed samples are found to be more crystalline and emit larger photoluminescence due to removal of quenching centers. The power dependent study of green upconversion emission indicates the involvement of two photons. The phosphor in La(OH)3 phase is more stable though the photoluminescence emission is slightly weak. La(OH)3 is less toxic compared to La2O3 and is biocompatible. It generates more heat and can be used in biothermal treatment.
authors.affiliation: Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India.
authors.forename: R S
authors.initials: RS
authors.lastname: Yadav
authors.affiliation: Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Verma
authors.affiliation: Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India.
authors.forename: A
authors.initials: A
authors.lastname: Bahadur
authors.affiliation: Laser & Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India. Electronic address: sbrai49@yahoo.co.in.
authors.forename: S B
authors.initials: SB
authors.lastname: Rai
mesh_terms: D007259:Infrared Rays; D007811:Lanthanum / Q000737:chemistry*; D049449:Luminescence; D049408:Luminescent Agents / Q000737:chemistry*; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D011221:Praseodymium / Q000737:chemistry*; D014961:X-Ray Diffraction; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D049408:Luminescent Agents; D010087:Oxides; C033562:lanthanum hydroxide; C103829:lanthanum oxide; D007811:Lanthanum; D015018:Ytterbium; D011221:Praseodymium
keywords: Infrared emission; Lanthanum hydroxide; Lanthanum oxide; Nano-phosphors; Upconversion