Gd³⁺-Doping Effect on Upconversion Emission of NaYF₄: Yb³⁺, Er³⁺/Tm³⁺ Microparticles

• Main Authors: Aleksandra A. Vidyakina, Ilya E. Kolesnikov, Nikita A. Bogachev, Mikhail Y. Skripkin, Ilya I. Tumkin, Erkki Lähderanta, Andrey S. Mereshchenko
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Materials
• Subjects: upconversion; luminescence; microcrystals; hydrothermal synthesis; rare earth
• Online Access: https://www.mdpi.com/1996-1944/13/15/3397
• ISSN: 1996-1944

β-NaYF₄ microcrystals co-doped with Yb³⁺, Er³⁺/Tm³⁺, and Gd<b>³⁺</b>ions were synthesized via a hydrothermal method using rare-earth chlorides as the precursors. The SEM and XRD data show that the doped β-NaYF₄ form uniform hexagonal prisms with an approximate size of 600–800 nm. The partial substitution of Y by Gd results in size reduction of microcrystals. Upconversion luminescence spectra of microcrystals upon 980 nm excitation contain characteristic intra-configurational ff bands of Er³⁺/Tm³⁺ ions. An addition of Gd³⁺ ions leads to a significant enhancement of upconversion luminescence intensity with maxima at 5 mol % of dopant.