title: Near-infrared down-conversion and energy transfer mechanism in Yb(3+)-doped Ba2LaV3O11 phosphors.
abstract: Yb(3+)-doped Ba2LaV3O11 vanadate phosphors with near-infrared (NIR) emission are synthesized via the sol-gel method. The phase purity and structure of samples are characterized by X-ray diffraction (XRD). The electronic structure of the self-activated phosphor host Ba2LaV3O11 is estimated by density functional theory (DFT) calculation, and the host absorption is mainly ascribed to the charge transition from the O-2p to V-3d states. Photoluminescence emission (PL) and excitation (PLE) spectra, decay curves, absorption spectra and theoretical quantum yields of samples are also investigated. Results indicate that Ba2LaV3O11:Yb(3+) phosphors have strong broad band absorption and efficient NIR emission, which matches well with the spectral response of the Si-based solar cells. The energy transfer processes from [VO4](3-) to Yb(3+) and possible transfer models are proposed based on the concentration of Yb(3+) ions. Results demonstrate that Ba2LaV3O11:Yb(3+) phosphors might act as a promising NIR DC solar spectral converter to enhance the efficiency of the silicon solar cells by utilizing broad band absorption of the solar spectrum.
authors.affiliation: National Key Laboratory of Photoelectric Technology and Functional Materials (Culture Base) in Shaanxi Province, National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Institute of Photonics & Photon-Technology, Northwest University, Xi'an 710069, China. guocf@nwu.edu.cn.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhao
authors.forename: Chongfeng
authors.initials: C
authors.lastname: Guo
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.forename: Dan
authors.initials: D
authors.lastname: Song
authors.forename: Xiangying
authors.initials: X
authors.lastname: Su