A multifunctional phosphor CaLaAl3O7: Eu2+, Eu3+ capable of achieving high sensitivity thermometry and wide color gamut ‘temperature mapping’

This study successfully synthesized a melilite-structured multifunctional phosphor, CaLaAl 3 O 7 : Eu 2+ , Eu 3+ , through solid-state reaction under reducing atmosphere. The phosphor demonstrates dual-band emission with contrasting temperature-dependent luminescence behaviors: the blue emission (Eu 2+ , 443 nm) exhibits a sharp intensity decline with rising temperature, whereas the red emission (Eu 3+ , 616 nm) shows only a slight decrease in intensity under the same conditions. This unique property enables high-sensitivity fluorescence thermometry, achieving a maximum relative thermometric sensitivity (S r ) of 2.59 % K −1 at 303 K. Moreover, by utilizing the significant luminescence color changes induced by temperature variations, we have achieved wide-gamut visualization of surface temperature distributions on objects. Under 365 nm UV excitation, the phosphor demonstrates persistent blue luminescence lasting 180 s due to defect energy levels. By integrating multi-wavelength selective excitation, long afterglow, wide color gamut emission, and high sensitivity temperature response, CaLaAl 3 O 7 : Eu 2+ , Eu 3+ demonstrates promising applications in visual temperature detection and information encryption/anti-counterfeiting.