Multicolor and multimodal luminescence in an Er 3+ single-doped double perovskite for advanced anti-counterfeiting and encryption

The Er 3+ single-doped NaGdTi 1.8 Al 0.2 O 6 double perovskite material achieves multicolor luminescence, afterglow, and upconversion emission by responding to several types of excitation ranging from UV to NIR and thermal disturbance.