Recently, near-infrared phosphors that can be applied in many fields such as night vision, agriculture, and bio-applications have attracted considerable interest in the research field worldwide. Herein, a multi-functional and...

Near-infrared spectroscopy is developing rapidly in the fields of human detection and food analysis due to its fast response and non-invasive characteristics.

Red/near infrared (NIR) long persistent phosphors have received extensive attentions in biomedical, food inspection, iris recognition, biological imaging, etc. Herein, a new phosphor, Li 2 ZnGe 3 O 8 :Cr 3+ , is reported with deep red persistent luminescence peaking at 708 nm. By adjusting the Cr 3+ doping concentration, the competitive site occupation at [ZnO6] and [GeO6] polyhedral enables different traps behaviors including trap types, trap concentration and trap depth, which in turn leads to different afterglow duration time from 2 to 20 h. The persistent luminescence mechanisms originated from different trap models have been discussed, and it is found that they can cooperate or inhibit each other, enabling different luminescence depending on time. The dynamic anti-counterfeiting applications have been demonstrated, which provides a new way to rationally designing for multi-functional luminescent materials.

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To make up for the cyan gap (480-520nm) in traditional tricolor (blue, green and red) phosphor-converted white light-emitting diodes (LEDs), it is highly important to find efficient cyan phosphors with...

Near infrared phosphor Ca3-xSrxY2Ge3O12:Cr3+ was synthesized by the solid-state method. When Sr2+ substituted for Ca2+, the thermal stability of the phosphor is obviously improved, and the emission intensity, at 150...

Multifunctional broadband near-infrared (NIR) Mg14Ge5O24: Mn4+, Cr, Yb3+ (MGO: Mn4+, Cr, Yb3+) phosphors were obtained by a solid-state method. An NIR emission band with a full width at half maximum of 320 nm was realized in the MGO: Cr, Yb3+ phosphor. The introduction of Yb3+ in MGO: Cr made the emission spectrum wider and improved the luminescence properties and thermal stability by energy transfer. The energy transfer mechanism was analyzed in detail. The improvement of NIR II luminescence was explored. A series of MGO: Mn4+, Cr samples were synthesized. The introduction of Mn4+ ions unexpectedly affects the crystal field of Cr4+. The decrease in the Stokes shift results in a decrease in nonradiative transition, so the probability of an effective electronic transition increases, and the emission intensity of Cr4+ has been improved to a certain extent. Finally, Mn4+, Cr, and Yb3+ tri-doped multifunctional near-infrared phosphors were obtained, and the applications of NIR I in the detection of hemoglobin concentration and detection of different biological tissues in NIR II proved that MGO: Mn4+, Cr, Yb3+ phosphors have great potential in the biological application field of NIR light-emitting diodes.

Narrow-band blue emitting phosphor KScSr1−yCaySi2O7:0.07Bi3+ with FWHM 40 nm.