Down-and upconversion luminescence in Er3+doped CaYAl3O7

The Er3+-doped materials have been intensively studied for applications in lighting, communication technologies, luminescence thermometry, anti-counterfeiting, solid-state lasers, etc. Er3+-doped materials demonstrate multi-mode luminescence excited with UV, Vis, and NIR radiation, opening a diverse field of applications in anti-counterfeiting, luminescence thermometry, etc. The properties of melilite-Type phosphor CaYAl3O7 doped with Er3+ ions have been studied for optical and optoelectronic applications. The samples were synthesized using the high-Temperature solid-state method and analysed by X-ray diffraction and optical spectroscopy techniques in the 8.5-300 K temperature range. The down-conversion and upconversion luminescence in Er3+-doped CaYAl3O7 was observed. At 8.5 K, the green emission at 552.4 nm increased 7.4 times in intensity compared to the room temperature, and the fluorescence intensity ratio (FIR) of 552.5nm/525.1 nm bands increased from 1.4 to 293.5 at 8.5 K offering applications of CYA:Er3+ in luminescence thermometry. The dominating mechanism of upconversion luminescence in the studied CYA:Er3+ powders is the excited-state absorption (ESA). The contribution of cross-relaxation processes in the Er3+ emission in the red spectral range (at 645-690 nm) was detected. The possibility of exciting CYA:Er3+ luminescence by UV, VIS, and NIR radiation makes CYA:Er3+ a promising component in technologies for anti-counterfeiting applications.