Cr 3+ -doped near-infrared phosphors have recently attracted a wide attention. Here, NIR Ca 1- y Sr y Al 12- x Ga x O 19 :0.12Cr 3+ phosphors are obtained by a high-temperature solid-phase method. First, a series of CaAl 7.88 Ga 4 O 19 :0.12Cr 3+ samples is studied and shows that the crystal field strength can be tuned by cation substitutions, until achieving a sharp emission at 692 nm and a broad emission at 780 nm under a 400 nm excitation, and an internal quantum yield of 90.73%. A further substitution by an appropriate amount of Sr 2+ is suggested to be beneficial to increase the rigidity of the crystal structure by Debye temperature calculations. Experimentally, it is observed that Sr 2+ for Ca 2+ substitutions did not affect the luminescence wavelength and resulted in a significant increase of the thermal stability. When 0.7 Sr 2+ substitute Ca 2+ , the thermal stability at 450 K increased by 28% compared to the samples without Sr 2+ .
Bingkai Gao,Lei Zhang,Runqiu Peng,Panlai Li,Qian Wu,Zhijun Wang
The exploration of performance luminescence near-infrared (NIR) material is crucial for rapidly developing NIR spectroscopic techniques. Herein, the NIR LaMg 0.5 Sn 0.5 O 3 :Cr 3+ phosphor was synthesized by a high temperature solid-state method. And its luminescence performance were improved by [In 3+ -Sc 3+ ] substituting for [Mg 2+ -Sn 4+ ]. The half-peak width can be expanded to 211 nm, the emission intensity can reach the seven times of that un-substitution, and the emission intensity at 423 K was maintained at 60 % of that at room temperature , moreover, the internal quantum efficiency can reach 54.2 %. On this basis, the phosphor converted light emitting diodes ( pc -LEDs) were achieved by combining La(Mg 1-x Sn 1-x In x Sc x ) 0.5 O 3 :Cr 3+ with blue LED, importantly, it can be applied to the biodetection and night vision lighting, which indicate its application value.
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