Energy-saving chromium-activated garnet-structured phosphor-converted near-infrared light-emitting diodes

Abstract

Phosphor-converted near-infrared light-emitting diodes (pc-NIR LED) are smart and energy-saving light sources as compared with the conventional tungsten halogen light bulb that will enable upcoming modern devices to meet the...

Shortwave Infrared Luminescence of Tetravalent Chromium and Divalent Nickel: Phosphor Design Principles and Applications

“…The choices of cations (A, B, and C) for garnet and their concurrent effect on the polyhedral features and their types are briefly discussed in our previous review paper. 7 One of the primary reasons for using garnet structures for Cr 4+ luminescence is their structural rigidity, which can provide higher quantum efficiency, thermal stability, and longer centered wavelengths. In addition, the garnet system offers a wider choice of chemical elements and can also be able to synthesize on a mass scale.…”

“…The significance and concept of this strategy are demonstrated in Cr 3+ -doped phosphors. 7 The substitution at the octahedral environment can directly regulate the crystal field strength around Ni 2+ ions. It is recognized that the crystal field strength is inversely proportional to the bond length of the localized octahedral environment.…”

“…In general, the chemical system with garnet structure will be expressed in the Ia 3̅ d space group of the cubic system with the generalized chemical formula of A 3 B 2 C 3 O 12 , and the cations A, B, and C will exist as the dodecahedral, octahedral, and tetrahedral polyhedral. The choices of cations (A, B, and C) for garnet and their concurrent effect on the polyhedral features and their types are briefly discussed in our previous review paper . One of the primary reasons for using garnet structures for Cr 4+ luminescence is their structural rigidity, which can provide higher quantum efficiency, thermal stability, and longer centered wavelengths.…”

“…One common and well-studied strategy for engineering the centered peak emission wavelength and fwhm of the phosphor is crystal-field-strength regulation. The significance and concept of this strategy are demonstrated in Cr 3+ -doped phosphors . The substitution at the octahedral environment can directly regulate the crystal field strength around Ni 2+ ions.…”

Does Cr3+Occupy Tetrahedral Sites and Luminesce in Oxides? A First-Principles Exploration

“…Broadband near-infrared (NIR) light has drawn much attention in the application field of organic analysis. , Numerous studies have been reported on broadband NIR emission with high thermal stability and high quantum efficiency produced by transition-metal activators. − In particular, Cr 3+ ion is the most preferred activator among these transition metals due to the good performance in these related aspects. − For example, La 3 Ga 5 GeO 14 :Cr 3+ has a broadband NIR emission with a full width at half-maximum (FWHM) of 330 nm, and Gd 3 Sc 2 Ga 3 O 12 :Cr 3+ has a near-unity internal quantum efficiency . The codoping of Cr 3+ and some rare earth ions (Yb 3+ , Eu 2+ , and Ce 3+ ) could further improve the properties of the NIR phosphors .…”