Multi-site occupancies of Dy3+ in Ca3Gd(AlO)3(BO3)4 and their optical thermometric applications

Lanthanide-doped Ca 3 Ln(AlO) 3 (BO 3 ) 4 phosphors are adopted for numerous new types of applications with outstanding optical properties. Herein, the novel Ca 3 Gd(AlO) 3 (BO 3 ) 4 :Dy 3+ phosphors were synthesized by the high-temperature solid-state method. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, diffuse reflection spectroscopy, and as well as photoluminescence (PL) spectra and lifetime curves are used to exemplify the resulting samples. This research explores the samples microstructure and the influence of Dy 3+ doping at the Ca and Gd sites. The PL spectrum results indicated that Ca 3 Gd(AlO) 3 (BO 3 ) 4 :Dy 3+ can be effectively excited by 349 nm UV light and emits bright white light results of Dy 3+ ions with the 4f–4f transition. The optimum doping content of the Dy 3+ in the Ca 3 Gd(AlO) 3 (BO 3 ) 4 host samples were 7 mol%, and the concentration quenching (CQ) mechanism was mainly owing to dipole–dipole interaction. Interestingly, the Ca 3 Gd 0.93 (AlO) 3 (BO 3 ) 4 :0.07Dy 3+ showed exceptional thermal-quenching resistance of > 87.3% intensity at 350 K. The temperature-sensing properties of Ca 3 Gd 0.93 (AlO) 3 (BO 3 ) 4 :0.07Dy 3+ ranging from 300 to 500 K were analyzed and had shown a decent maximum S A value about 1.35% K −1 at 500 K between 455 and 669 nm fluorescence intensity ratio. Hence, the novel Ca 3 Gd 0.93 (AlO) 3 (BO 3 ) 4 :0.07Dy 3+ materials could be a competent candidate for low-cost and non-contact optical thermometry in a high-temperature environment.