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Monitoring the real‐time quality and validity of thermo‐sensitive foods during storage and transportation can be achieved with time‐temperature indicators (TTIs). However, the available TTIs still need to be improved in terms of accuracy, recoverability, environmental tolerance, and quantitative monitoring. Here, a novel TTI based on the optical signals originating from the as‐explored Sr3Y2Ge3O12: Mn2+, Er3+ (SYGO: Mn2+, Er3+) phosphor is developed. Thanks to the fact that the release of the captured carriers is tightly related to the storage time and ambient temperature, distinct optical signals of the as‐obtained TTI under multi‐stimulus (980 nm laser irradiation, thermal stimulation, and mechanical force) can be distinguished to judge the validity of temperature‐sensitive products. This work reveals the promising potential of SYGO: Mn2+, Er3+ phosphors with cryogenic optical storage properties as advanced TTIs, especially for packaged products in cold chain logistics. [ABSTRACT FROM AUTHOR]

Scintillators, as the core materials for X‐ray imaging, have received great attention in radiation detection, security inspection, and biomedical applications. However, the current single crystal and thin film scintillators have encountered several issues, such as high cost, insufficient stability, and uneven distribution, which undoubtedly limit the development of high‐quality X‐ray imaging. Herein, the Y3Al5O12:Ce3+ (YAG:Ce3+) transparent ceramics (TCs), which presented a high transmittance of 82% and a steady‐state light yield of 24 600 photons MeV−1, are prepared by the vacuum solid‐state reactive sintering method. The fabricated YAG:Ce3+ TCs exhibit X‐ray imaging with an excellent spatial resolution (≈34.7 lp mm−1). Moreover, because of the structural stability of YAG:Ce3+ TCs, long‐term stable work under X‐ray irradiation is realized successfully. This work indicates that the TC scintillators provide a new opportunity for the development of high‐quality X‐ray imaging. [ABSTRACT FROM AUTHOR]

Broadband near‐infrared (NIR) luminescent materials have received notable attention due to their distinct photophysical properties for designing NIR light‐emitting diodes (NIR LEDs). Here, a series of Ca3−xLuxGa2+xGe3−xO12:Cr3+ (CLGGG:Cr3+) (x = 0–1) NIR‐emitting garnet phosphors with an emission range of 660–1200 nm are successfully developed and their lattice parameters are structurally analyzed. Upon 460 nm blue light excitation, the NIR phosphors exhibit both a substantial spectral broadening (FWHM: 129→267 nm) and a redshift of 37 nm (766→803 nm) with cosubstitution of [Lu3+–Ga3+] pairs for [Ca2+–Ge4+] sites. Furthermore, their luminescence thermal stability is substantially improved, maintaining ≈90% of the original photoluminescence intensity at 150 °C, owing to shrinkage of the second coordination sphere and rigid lattice, which are strongly associated with Cr3+ trade‐off occupancy and local structure evolutions. The relation between the trade‐off site occupation of Cr3+ in GaO6/CaO8 polyhedrons and the NIR emission is also clarified by evaluating the decay and electron paramagnetic resonance behavior of Cr3+ at different sites. The broadband NIR phosphors investigated here can serve as auspicious luminescent converters for phosphor‐converted NIR LEDs and can provide an inspiring platform for future studies. [ABSTRACT FROM AUTHOR]