Excellent thermal stability of Y2.94Al4−xSixGaO12: 0.06Ce3+ phosphor for optical storage

Highlights: • A new type of Y_2.94Al_4−xSi_xGaO₁₂: 0.06Ce³⁺ phosphors with weak thermal quenching and long afterglow were synthesized by the conventional solid-state reaction route. • 88% of the room-temperature emission intensity is still maintained at 453 K, indicating a good thermal stability and practicality. • It should be noted that the encoding process does not require a specific wavelength light source, but ordinary sunlight. -- Abstract: In order to prepare various Y_2.94Al_4−xSi_xGaO₁₂: 0.06Ce³⁺ phosphors, a traditional approach to solid-state reaction was adopted. XRD and Rietveld were refined to confirm the cubic garnet crystal structure of phosphors. Besides, the substance displayed a wide mission band varying between 475 nm and 650 nm due to the 5d→4f transitions of the Ce³⁺ ions as excited by a 450 nm wavelength. Furthermore, as the Si⁴⁺ concentration increases from 0 to 0.6, we can observe a blue shift in the emission spectrum from 510 nm to 502 nm. The emission intensity at 453 K is still 88% of that at room temperature. At the same time, through the auxiliary calculation of activation energy, the advantages of thermal stability and the weakness of thermal quenching are explained. Surprisingly, a demonstrational application confirmed the excellent capability of optical data retention in encoding/decoding the material, including a designed bar code and graphic patterns. It is suggested that phosphor is applicable for the development of white LEDs based on the blue LED-chip. In particular, when some unexpected circumstances occur and lighting conditions suddenly break down, LED with long afterglow performance can alleviate the discomfort caused by the change. It is also expected to move forward the study on Long-lasting phosphorescence (LLP) materials and their practical application in optical storage.