Trap Depth Engineering of SrSi₂O₂N₂:Ln²⁺,Ln³⁺ (Ln²⁺ = Yb, Eu; Ln³⁺ = Dy, Ho, Er) Persistent Luminescence Materials for Information Storage Applications

Abstract

Deep-trap persistent luminescence materials exhibit unique properties of energy storage and controllable photon release under additional stimulation, allowing for both wavelength and intensity multiplexing to realize high-capacity storage in the next-generation information storage system. However, the lack of suitable persistent luminescence materials with deep traps is the bottleneck of such storage technologies. In this study, we successfully developed a series of novel deep-trap persistent luminescence materials in the Ln/Ln-doped SrSiON system (Ln = Yb, Eu; Ln = Dy, Ho, Er) by applying the strategy of trap depth engineering. Interestingly, the trap depth can be tailored by selecting different codopants, and it monotonically increases from 0.90 to 1.18 eV in the order of Er, Ho, and Dy. This is well explained by the energy levels indicated in the host-referred binding energy scheme. The orange-red-emitting SrSiON:Yb,Dy and green-emitting SrSiON:Eu,Dy phosphors are demonstrated to be good candidates of information storage materials, which are attributed to their deep traps, narrow thermoluminescence glow bands, high emission efficiency, and excellent chemical stability. This work not only validates the suitability of deep-trap persistent luminescence materials in the information storage applications, but also broadens the avenue to explore such kinds of new materials for applications in anticounterfeiting and advanced displays.

Long persistent and photo‐stimulated luminescence in Pr3+‐doped layered perovskite phosphor for optical data storage

“…Humans are entering an era of big data as the storage of information from many activities of human beings has undergone explosive growth in the past decades . It has been estimated that the information generated by the major sectors, including education, health, business and so on, is nearly doubling yearly .…”

Identifying Near‐Infrared Persistent Luminescence in Cr3+‐Doped Magnesium Gallogermanates Featuring Afterglow Emission at Extremely Low Temperature

“…On the other hand, the release rate of charge carriers captured in very deep traps is extremely low at RT, leading to a slow detrapping process. Phosphors containing very deep traps are usually used as storage phosphors for dosimetry or information storage security systems instead of the room‐temperature afterglow applications …”

A Photostimulated BaSi2O5:Eu2+,Nd3+ Phosphor‐in‐Glass for Erasable‐Rewritable Optical Storage Medium

“…Photostimulated luminescence (PSL) material, also called as electron trapping material, can store irradiation energy from X‐ray, ultraviolet (UV), or visible light by capturing the created charge carriers in traps, and then release the stored energy upon low‐energy light stimulation, thus theoretically can be used for data encoding/decoding . Albeit this conceptual proposal already existed for years, until very recently PSL was experimentally demonstrated applicable for multidimensional optical data storage, showing intensity‐ and wavelength‐multiplexing . The main reason to this lies in the shortage of satisfactory PSL material to meet the stringent requirements in optical storage: 1) the traps ought to be deep to prevent information loss; 2) the deep traps should have narrow distribution to cater to the stimulated near‐infrared (NIR) light; and 3) in order to achieve good durability of stored optical signal, there is supposed to be no significant interference between shallow and deep traps (the redeployment of charge carriers between shallow and deep traps as time leads to signal attenuation) .…”