Spectroscopic studies of K2GdF5:Nd3+ single crystals for incredibly strong NIR emission at 864 nm

• Published in: The Journal of physics and chemistry of solids 2022-02, Vol.161, p.110454, Article 110454
• Main Authors: Van Tuyen, Ho, Khaidukov, Nicholas M., Quang, Vu Xuan, Thuy, Nguyen Thi Minh, Ca, Nguyen Xuan, Thanh, Luong Duy, Hung, Nguyen Manh, Du, Pham Tien, Van Do, Phan
• Format: Article
• Language: English
• Subjects: Judd-Ofelt theory; K2GdF5 single crystal; Yokota-Tamimoto model
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/j.jpcs.2021.110454

K2GdF5 single crystals doped with 5.0 at.% of Nd3+ ions (K2GdF5:Nd3+) were synthesized by the hydrothermal technique. The identification and control of the phase purity of synthesized crystals were performed using powder X-ray diffraction analysis. The spectroscopic characteristics of Nd3+ ions in K2GdF5 were analyzed through the absorption and luminescence spectra as well as decay curves. Upconversion luminescence spectra of K2GdF5:Nd3+ in the visible region were recorded under excitation by laser radiation with a wavelength of 785 nm. The nature of the Nd3+- ligand bonding and Judd-Ofelt intensity parameters were estimated using the absorption spectrum. The Ω4/Ω6 ratio was used to predict the structure of the emission spectrum of the K2GdF5:Nd3+ crystal. The application capability of the 4F3/2 → 4I9/2 emission band (864 nm) for laser action in K2GdF5:Nd3+ is proposed based on the radiative parameters such as the experimental branching ratio (βexp), integrated emission cross-section (ΣJJ’) and stimulated emission cross-sections (σλp). The nonradiative energy transfer process between Nd3+ ions in K2GdF5:Nd3+ is also discussed in detail using the Inokuti-Hirayama and Yokota-Tamimoto models. •+ K2GdF5:Nd3+ single crystals are prepared by hydrothermal method at temperature of 750 K and pressure of 1500 MPa.•+ Luminescence spectra of the K2GdF5:Nd3+ indicate an incredibly strong band at 864 nm.•+ Judd-Ofelt analysis shows the high application ability of K2GdF5:Nd3+ in laser action.•+ Upconversion luminescence of K2GdF5:Nd3+ is observed under excitation by 785 nm laser.•+ Energy transfer in K2GdF5:Nd3+ relates mainly to the energy migration mechanism.