# Up-conversion Luminescence Characterization of CeO2:Ho3+/Yb3+ Particles Prepared by Spray Pyrolysis

Jung, Kyeong Youl;Min, Byeong Ho;Kim, Dae Sung;Choi, Byung-Ki

• Accepted : 2019.02.28
• Published : 2019.06.25
• 14 3

#### Abstract

Spherical $CeO_2:Ho^{3+}/Yb^{3+}$ particles were synthesized using spray pyrolysis, and the upconversion (UC) properties were investigated with changing the preparation conditions and the infrared pumping power. The resulting particles had a size of about $1{\mu}m$ and hollow structure. The prepared $CeO_2:Ho^{3+}/Yb^{3+}$ particles exhibited intense green emission due to the $^5F_4/^5S_2{\rightarrow}^5I_8$ transition of $Ho^{3+}$ and showed weak red or near-IR peaks. In terms of achieving the highest UC emission, the optimal concentrations of $Ho^{3+}$ and $Yb^{3+}$ were 0.3% and 2.0%, respectively. The UC emission intensity of prepared $CeO_2:Ho^{3+}/Yb^{3+}$ particles had a linear relationship with crystallite size and concentration quenching was caused by dipole-dipole interaction between the same ions. Based on the dependency of UC emission on the pumping power, the observed green upconversion was achieved through a typical two-photon process and concluded that the main energy transfer from $Yb^{3+}$ to $Ho^{3+}$ was involved in the ground-state adsorption (GSA) process.

#### Keywords

Spray pyrolysis;Phosphor;Upconversion;Energy transfer

#### Acknowledgement

Supported by : Ministry of Trade, Industry & Energy