High quantum-yield phosphors via quantum splitting and upconversion Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/rv042w959

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • The Gd3+ ion has been used to induce quantum splitting in luminescent materials by using cross-relaxation energy transfer (CRET). In Nd:LiGdF4, quantum splitting results from a two-step CRET between Gd3+ and Nd3+, first involving a transition 6G→6I on Gd3+ and an excitation within the 4f3 configuration of Nd3+ followed by a second CRET that brings Gd3+ to 6P7/2. The excited Nd3+ ion rapidly relaxes nonradiatively to the emitting 4F3/2. The excited Gd3+ ion then transfers its energy back to Nd3+, which gives rise to the second photon. The result is a quantum yield of 1.05 ± 0.35 with emission in the NIR following excitation at 175 nm. GdF3:Pr3+, Eu3+ also exhibits quantum splitting, but only at very low concentration of Pr3+ (0.3%) and Eu3+ (0.2%), resulting in a quantum yield of approximately 20% under 160-nm excitation. Host intrinsic emission via a self-trapped exciton (STE) was also examined as a means to sensitize Gd3+ emission. The material ScPO4:Gd3+ exhibits a high absolute quantum yield of 0.9 ± 0.2 under 170-nm excitation, demonstrating a potentially new and efficient pathway for exciting quantum splitting phosphors. Single crystals of the material GdZrF7 were grown, and its structure was established via single-crystal X-ray diffraction methods. Doped samples of GdZrF7:Yb3+, Er3+ exhibit bright up-conversion luminescence with light output that is up to twice that of a commercial material based on the host Gd2O2S. When doped with Eu3+, the fluoride also emits a nearly white color under vacuum ultraviolet excitation with an absolute quantum yield near 0.9. The new compound Gd4.67(SiO4)3S was synthesized and studied. The structure was established via single-crystal X-ray methods, and the luminescence of Tb3+ samples was investigated.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Keyword
Subject
Rights Statement
Language
File Format
File Extent
  • 4623969 bytes
Replaces
Additional Information
  • description.provenance : Submitted by Joa-young Jeong (jeongjo@onid.orst.edu) on 2007-12-31T21:23:46Z No. of bitstreams: 1 Jeong_thesis.pdf: 4623969 bytes, checksum: 9f0735eda6289c55d6ba5ff1a63bf93d (MD5)
  • description.provenance : Approved for entry into archive by Linda Kathman(linda.kathman@oregonstate.edu) on 2008-01-10T14:46:16Z (GMT) No. of bitstreams: 1 Jeong_thesis.pdf: 4623969 bytes, checksum: 9f0735eda6289c55d6ba5ff1a63bf93d (MD5)
  • description.provenance : Approved for entry into archive by Julie Kurtz(julie.kurtz@oregonstate.edu) on 2008-01-02T16:26:37Z (GMT) No. of bitstreams: 1 Jeong_thesis.pdf: 4623969 bytes, checksum: 9f0735eda6289c55d6ba5ff1a63bf93d (MD5)
  • description.provenance : Made available in DSpace on 2008-01-10T14:46:17Z (GMT). No. of bitstreams: 1 Jeong_thesis.pdf: 4623969 bytes, checksum: 9f0735eda6289c55d6ba5ff1a63bf93d (MD5)

Relationships

In Administrative Set:
Last modified: 08/14/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items