Designing multi-mode optical thermometers via the thermochromic LaNbO4:Bi3+/Ln3+ (Ln = Eu, Tb, Dy, Sm) phosphors

The practical application of near-infrared (NIR) phosphors is hindered due to their limited light emitting region and narrow bandwidth. Here, we report a series of Cr3+-doped olivine phosphors, (Mg1−xLix)(Mg1−xScx)GeO4:Cr3+, with tunable luminescence from NIR-I to NIR II based on crystallographic site engineering. By using a [Li+–Sc3+] unit substituting for a [Mg2+–Mg2+] unit, the NIR luminescence can be largely tuned from 940 nm to 1110 nm, and the corresponding FWHM can be modified from 236 to ∼300 nm. The internal quantum efficiency (IQE) and external quantum efficiency (EQE) of Mg2GeO4:1% Cr3+ were measured to be 48.19% and 16.38%, respectively. The photoluminescence of the phosphors matches well with the absorption of several functional groups. By measuring the NIR absorption of different liquids illuminated by NIR light from our phosphors, qualitative and quantitative analysis can be realized. These results suggest that the super-broad NIR luminescence of (Mg1−xLix)(Mg1−xScx)GeO4:Cr3+ has potential applications as light sources for nondestructive food analysis.

Tuning luminescence from NIR-I to NIR-II in Cr3+-doped olivine phosphors for nondestructive analysis

Li/Na substitution and Yb3+ co-doping enabling tunable near-infrared emission in LiIn2SbO6:Cr3+ phosphors for light-emitting diodes

Abstract Near-infrared (NIR)-emitting phosphor-converted light-emitting diodes have attracted widespread attention in various applications based on NIR spectroscopy. Except for typical Cr 3+ -activated NIR-emitting phosphors, next-generation Cr 3+ -free NIR-emitting phosphors with high efficiency and tunable optical properties are highly desired to enrich the types of NIR luminescent materials for different application fields. Here, we report the Fe 3+ -activated Sr 2− y Ca y (InSb) 1− z Sn 2 z O 6 phosphors that exhibit unprecedented long-wavelength NIR emission. The overall emission tuning from 885 to 1005 nm with broadened full-width at half maximum from 108 to 146 nm was realized through a crystallographic site engineering strategy. The NIR emission was significantly enhanced after complete Ca 2+ incorporation owing to the substitution-induced lower symmetry of the Fe 3+ sites. The Ca 2 InSbO 6 :Fe 3+ phosphor peaking at 935 nm showed an ultra-high internal quantum efficiency of 87%. The as-synthesized emission-tunable phosphors demonstrated great potential for NIR spectroscopy detection. This work initiates the development of efficient Fe 3+ -activated broadband NIR-emitting phosphors and opens up a new avenue for designing NIR-emitting phosphor materials. 

https://www.nature.com/articles/s41377-022-00803-x.pdf

Highly efficient Fe3+-doped A2BB′O6 (A = Sr2+, Ca2+; B, B′ = In3+, Sb5+, Sn4+) broadband near-infrared-emitting phosphors for spectroscopic analysis

Adjustable photoluminescence of Bi3+ and Eu3+ in solid solution constructed by isostructural end components through composition and excitation-driven strategy

Long persistent phosphors (LPPs) with ultraviolet (UV) luminescence have great potential for application in the fields of biomedicine, environmental, and catalysis. However, it is currently limited...

Ultraviolet-A Persistent Luminescence of a Bi3+-Activated LiScGeO4 Material

Rechargeable and sunlight-activated Sr3Y2Ge3O12:Bi3+ UV–Visible-NIR persistent luminescence material for night-vision signage and optical information storage

Near-infrared (NIR) persistent luminescence (PersL) materials have recently evoked considerable interest in the field of biomedicine, but the choices of efficient emitters for NIR PersL phosphors are rather limited. Herein, we report a new class of Fe3+-activated NIR PersL phosphor based on the LiGaO2 host, which exhibits an intense NIR PersL at around 748 nm and possesses an ultra-long PersL time of much longer than 26 h. The optical properties of this phosphor as well as the trapping and de-trapping processes, the trap characteristics, and the underlying PersL mechanism are comprehensively studied by means of photoluminescence (PL), PersL, electron paramagnetic resonance (EPR), thermoluminescence (TL), and X-ray photoelectron spectroscopies (XPS). It was found that the NIR PersL in this material is closely related to the oxygen vacancies. Furthermore, the penetration experiments and cytotoxicity tests of the biological tissue show that this material has great potential for bioimaging applications. Our achievement in the case of nontoxic Fe3+-activated LiGaO2 phosphors lays the foundation for the future design of Cr3+-free PersL phosphors with efficient NIR PersL towards versatile bioapplications.

Zhihao Zhou

Papers

Ultraviolet-A Persistent Luminescence of a Bi3+-Activated LiScGeO4 Material

Rechargeable and sunlight-activated Sr3Y2Ge3O12:Bi3+ UV–Visible-NIR persistent luminescence material for night-vision signage and optical information storage

Cr3+-Free near-infrared persistent luminescence material LiGaO2:Fe3+: optical properties, afterglow mechanism and potential bioimaging

Self‐activated persistent luminescence from Ba2Zr2Si3O12 for information storage

Defect Enrichment in Near Inverse Spinel Configuration to Enhance the Persistent Luminescence of Fe3