To view this presentation:

  • If you have an MRS account, click the Login button above.
  • New to MRS?  Create a free account here



  0       0

2014 MRS Spring Meeting


QQ5.05 - Surface Effects on the Upconversion Dynamics in NaYF:Yb:Er Nanoparticles


Apr 23, 2014 2:45pm ‐ Apr 23, 2014 3:00pm

Description

Upconversion luminescence for NaYF:Yb:Er nanoparticles shows a marked decrease in quantum efficiency and much faster rates in the rise and fall of the luminescence decay curves as compared to bulk NaYF:Yb:Er. We propose that in moving from µm-sized to nm-sized β-NaYF:Yb:Er particles, the effects observed in the decay curves can be mostly accounted for by the changes in only three rate constants, namely the non-radiative rate constant of Yb (kYb), the non-radiative rate constant for Er from I to I (k) and the non-radiative rate constant for Er from I to I (k). The increase in the effective values for kYb and k occurs because rapid energy migration among the levels emitting near 1 µm leads to equilibration between interior and surface sites, with a consequent increase over bulk values in the two rate constants relating to the non-radiative decay of these levels. The increase in k also results from this rapid energy migration, since most of the Er: I to I emission comes from surface sites where I is rapidly quenched to I. The changes that occur in the visible upconversion luminescence (red, green, and blue) are simply a reflection of the faster quenching at 1 µm. Computational analysis through a non-linear rate equation model of the upconversion process supports this hypothesis.

Speaker(s):

  • Amy Hor, South Dakota School of Mines and Technology, University of South Dakota

You must be logged in and own this session in order to post comments.

Print Certificate
Review Answers
Print Transcript
Completed on: token-completed_on
Review Answers
Please select the appropriate credit type:
/
test_id: 
credits: 
completed on: 
rendered in: 
* - Indicates answer is required.
token-content

token-speaker-name
token-index
token-content
token-index
token-content
token-index
token-content
token-index
token-content
token-index
token-content
token-index
token-content
/
/
token-index
token-content
token-index
token-content