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There is great interest in advancing optical anti-counterfeiting technology for use in information security, but the emission colors of traditional anti-counterfeiting phosphors vary depending on the stimulation source, which diminishes the difficulty of counterfeiting. Persistent luminescence (PersL) phosphors are particularly suitable for anti-counterfeiting applications because of their multimodal luminescence features. Herein, a PersL phosphor Sr2Ta2O7:Tb3+, Tm3+ exhibited emission independence from the stimulation source, and emitted stable and reliable blue-green luminescence in down-conversion luminescence, PersL, up-conversion luminescence, and photo-stimulated luminescence. Depending on the multimodal luminescence features of Sr2Ta2O7:Tb3+/Tm3+ phosphors, numerous patterns were successfully obtained to confirm its excellent anti-counterfeiting ability. This work illustrates the potentiality of the stimulated-source-independent multi-mode anti-counterfeiting long-lasting phosphor Sr2Ta2O7:Tb3+/Tm3+ as a viable strategy for developing highly secure materials. [ABSTRACT FROM AUTHOR]

Cr3+ activated near‐infrared (NIR) phosphors are getting unprecedented attention to fabricate the broad band NIR light emitting diodes (NIR‐LEDs) for nondestructive detection, bio‐imaging, and night vision. However, it remains a major challenge to obtain ultrabroadband NIR emitting phosphor with excellent quantum yield (QY). Here, a broadband NIR emitting phosphor Mg7Ga2GeO12:Cr3+ (MGGO: Cr3+) ranging from 600 to 1300 nm with an outstanding QY (93%) and large full width of half maximum (FWHM = 226 nm) is developed, in which the site occupancy tendency of Cr3+ in MGGO host is discussed in detail through combining the structure optimization and the first‐principles theory calculation with luminescent properties at low temperature. After that, the emission intensity of MGGO:Cr3+ is improved through partial substitution of Mg2+ by alkaline‐earth ions Ca2+, Sr2+, or Ba2+, and the luminescence enhancement mechanism is also investigated. Furthermore, the NIR pc‐LED device is fabricated by combining 450 nm blue LED chip with the brightest phosphor MGGO:Cr3+/Ba2+, and its potential applications are evaluated in the field of nondestructive detection, night vision, and bio‐imaging. [ABSTRACT FROM AUTHOR]

Cr3+ activated near‐infrared (NIR) phosphors are getting unprecedented attention to fabricate the broad band NIR light emitting diodes (NIR‐LEDs) for nondestructive detection, bio‐imaging, and night vision. However, it remains a major challenge to obtain ultrabroadband NIR emitting phosphor with excellent quantum yield (QY). Here, a broadband NIR emitting phosphor Mg7Ga2GeO12:Cr3+ (MGGO: Cr3+) ranging from 600 to 1300 nm with an outstanding QY (93%) and large full width of half maximum (FWHM = 226 nm) is developed, in which the site occupancy tendency of Cr3+ in MGGO host is discussed in detail through combining the structure optimization and the first‐principles theory calculation with luminescent properties at low temperature. After that, the emission intensity of MGGO:Cr3+ is improved through partial substitution of Mg2+ by alkaline‐earth ions Ca2+, Sr2+, or Ba2+, and the luminescence enhancement mechanism is also investigated. Furthermore, the NIR pc‐LED device is fabricated by combining 450 nm blue LED chip with the brightest phosphor MGGO:Cr3+/Ba2+, and its potential applications are evaluated in the field of nondestructive detection, night vision, and bio‐imaging. [ABSTRACT FROM AUTHOR]

Synergistic therapy combining photothermal therapy and photodynamic therapy is considered to be a promising approach to treat cancer, but the precise temperature control of deep tissue remains a great challenge in achieving effective treatment. Herein, a two-dimensional Bi 2 WO 6 :Nd 3+ /Yb 3+ /Er 3+ @MoS 2 nanoplatform with photothermal and photodynamic functions was constructed, where semiconductor MoS 2 serves as both a photothermal agent and a photosensitizer. The photothermal conversion performance and the reactive oxygen species generation capacity of the nanoplatform were validated under the irradiation of 808 nm laser; meanwhile, the two sets of luminescence intensity ratios ( I Yb3+ / I Nd3+ and I Er3+ / I Nd3+ ) in the biological window region were selected as near-infrared temperature probes to monitor the heat generated during the photosynergistic process in real time. The feasibility of nanoplatform as an intratissue temperature probe and antibacterial agent was further assessed by vitro experiments, which provides an idea for designing multifunctional photosynergistic therapy nanoplatform.

Based on luminescence intensity ratio (LIR) technology, the noncontact upconversion (UC) optical temperature sensor has aroused a great deal of interest due to its great application prospects in some extreme environments. However, most of the studies focused on improving its sensitivity due to the fact that the sensitivity can be influenced by many external field factors, such as the power density and pulse width of pumping sources or temperature. Herein, a green-emitting UC phosphor Sr 2 InF 7: Yb 3+ , Er 3+ was developed as a potential thermometer, which retained bright green emission under 980 nm excitation with different pulse widths and power densities or at different temperatures; the possible mechanisms are discussed in detail. Its sensitivity almost remained constant when using both continuous wave (c.w.) and pulsed laser or different power densities, which meant the sensitivity of Sr 2 InF 7: Yb 3+ , Er 3+ was independent of the characteristics of pumping laser. A flexible thin-film thermometer composed of Sr 2 InF 7 : 2%Yb 3+ , 2%Er 3+ was also fabricated to detect the temperature of microelectronic components, which can not only accurately measure the temperature of the working electronic circuit board but also exhibit excellent repeatability. The results indicated that the present noncontact UC temperature sensor showed stable green emission and thermometric sensitivity as well as the possibility of replacing the traditional thermometers.