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Title: Increased fluorescence intensity in CaTiO 3:Pr 3+ phosphor due to NH 3 treatment and Nb Co-doping

Abstract

Development of next generation red phosphors for commercial lighting requires understanding of how increased luminescence is achieved by various treatment strategies. In our work, we compare co-doping with Nb to NH 3 treatment of CaTiO 3:Pr phosphors to reveal a general mechanism responsible for the increased luminescence. The phosphors were synthesized using standard solid-state synthesis techniques and the fluorescence was characterized for potential use in fluorescent lighting, with 254 nm excitation. The lifetime of the fluorescence was determined and used to identify a change in a trap state by the co-doping of Nb 5+ in the phosphor. Furthermore, the oxidation state of the Pr was probed by NEXAFS and revealed that both Nb 5+ co-doping and NH 3 treatment reduced the number of non-fluorescing Pr 4+ centers. We performed calculations in order to determine the energetically favorable defects. Vacuum annealing was also used to further probe the nature of the trap state. It was determined that NH 3 treatments reduce the number of Pr 4+ non-fluorescing centers, while Nb 5+ co-doping additionally reduces the number of excess oxygen trap states that quench the fluorescence.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [2];  [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. GE Global Research, Niskayuna, New York (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1336996
Report Number(s):
LLNL-JRNL-703658
Journal ID: ISSN 0925-3467
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Optical Materials
Additional Journal Information:
Journal Volume: 60; Journal Issue: C; Journal ID: ISSN 0925-3467
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Red phosphor; Calcium titanate; Praseodymium emission; Lighting phosphor

Citation Formats

Holliday, K. S., Kohlgruber, T. A., Tran, I. C., Åberg, D., Seeley, Z. M., Bagge-Hansen, M., Srivastava, A. M., Cherepy, N. J., and Payne, S. A.. Increased fluorescence intensity in CaTiO3:Pr3+ phosphor due to NH3 treatment and Nb Co-doping. United States: N. p., 2016. Web. doi:10.1016/j.optmat.2016.08.016.
Holliday, K. S., Kohlgruber, T. A., Tran, I. C., Åberg, D., Seeley, Z. M., Bagge-Hansen, M., Srivastava, A. M., Cherepy, N. J., & Payne, S. A.. Increased fluorescence intensity in CaTiO3:Pr3+ phosphor due to NH3 treatment and Nb Co-doping. United States. doi:10.1016/j.optmat.2016.08.016.
Holliday, K. S., Kohlgruber, T. A., Tran, I. C., Åberg, D., Seeley, Z. M., Bagge-Hansen, M., Srivastava, A. M., Cherepy, N. J., and Payne, S. A.. 2016. "Increased fluorescence intensity in CaTiO3:Pr3+ phosphor due to NH3 treatment and Nb Co-doping". United States. doi:10.1016/j.optmat.2016.08.016. https://www.osti.gov/servlets/purl/1336996.
@article{osti_1336996,
title = {Increased fluorescence intensity in CaTiO3:Pr3+ phosphor due to NH3 treatment and Nb Co-doping},
author = {Holliday, K. S. and Kohlgruber, T. A. and Tran, I. C. and Åberg, D. and Seeley, Z. M. and Bagge-Hansen, M. and Srivastava, A. M. and Cherepy, N. J. and Payne, S. A.},
abstractNote = {Development of next generation red phosphors for commercial lighting requires understanding of how increased luminescence is achieved by various treatment strategies. In our work, we compare co-doping with Nb to NH3 treatment of CaTiO3:Pr phosphors to reveal a general mechanism responsible for the increased luminescence. The phosphors were synthesized using standard solid-state synthesis techniques and the fluorescence was characterized for potential use in fluorescent lighting, with 254 nm excitation. The lifetime of the fluorescence was determined and used to identify a change in a trap state by the co-doping of Nb5+ in the phosphor. Furthermore, the oxidation state of the Pr was probed by NEXAFS and revealed that both Nb5+ co-doping and NH3 treatment reduced the number of non-fluorescing Pr4+ centers. We performed calculations in order to determine the energetically favorable defects. Vacuum annealing was also used to further probe the nature of the trap state. It was determined that NH3 treatments reduce the number of Pr4+ non-fluorescing centers, while Nb5+ co-doping additionally reduces the number of excess oxygen trap states that quench the fluorescence.},
doi = {10.1016/j.optmat.2016.08.016},
journal = {Optical Materials},
number = C,
volume = 60,
place = {United States},
year = 2016,
month = 8
}

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