Revisiting the NIR-to-Visible Upconversion Mechanism in β-NaYF4:Yb(3+),Er(3.).
Here, we show that the long-accepted mechanism for the production of red and blue emission through upconversion (UC) of 1 μm excitation in Yb(3+)/Er(3+)-doped materials does not apply in the popular β-NaYF4 host. We propose a new mechanism involving Yb(3+)-to-Er(3+) energy-transfer UC out of the green-emitting (2)H11/2,(4)S3/2 states that quantitatively accounts for all of the observed optical behavior. Rate constants for the relevant radiative and nonradiative processes are reported along with a prediction of the power dependence of the pulsed and continuous-wave UC quantum efficiency.
†Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, 501 East Saint Joseph Street, Rapid City, South Dakota 57701, United States.
Robert B
RB
Anderson
†Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, 501 East Saint Joseph Street, Rapid City, South Dakota 57701, United States.
Steve J
SJ
Smith
‡Department of Chemistry, University of South Dakota, 414 East Clark Street, Vermillion, South Dakota 57069, United States.
P Stanley
PS
May
‡Department of Chemistry, University of South Dakota, 414 East Clark Street, Vermillion, South Dakota 57069, United States.
Mary T
MT
Berry
energy-transfer upconversion; erbium; lanthanide; mechanism; ytterbium