Eu²⁺‐Doped Layered Double Borate Phosphor with Ultrawide Near‐Infrared Spectral Distribution in Response to Ultraviolet–Blue Light Excitation

Abstract

As the core component of this emerging field, the broadband NIR light source needs to be small and exquisite to meet the application requirements. Compared with traditional broadband NIR light sources such as the bulky tungsten-halogen lamps, broadband NIR phosphor-converted light-emitting diodes (NIR pc-LEDs) is proposed as an ideal compact light source due to their advantages of environmental protection, energy-saving, long lifetime, and small size. [2] The strategy of NIR pc-LEDs is mainly realized by coating broadband NIR phosphor on a blue LED chip. Among them, one of the important research topics is the exploration of broadband NIR phosphors that can be excited by blue light.Cr 3+ ion with d 3 electron configuration is the commonly used activator for NIR emitting phosphors. When it's located in a weak octahedral crystal field in a host, broadband NIR emission can be obtained due to the 4 T 2 → 4 A 2 transition. [3] The Cr 3+ -doped garnet phosphors are a typical broadband NIR luminescent material, showing high quantum efficiency and robust thermal stability. For example, Ca

Broadband Yellow Phosphor Discovered by Single-Particle Analysis Based on Fluorescence Microscopy, Scanning Electron Microscopy, Cathodoluminescence, and Energy-Dispersive X-ray Spectroscopy

“…The relationship between Lg­( x ) and Lg­(I/ x ) was fitted linearly with a slope of −1.07, as exhibited in Figure d. The value of θ was calculated to be approximately 3.2, which was close to 6 . Thus, the dipole–dipole interaction was the dominant mechanism of concentration quenching in this work.…”

“…The value of θ was calculated to be approximately 3.2, which was close to 6. 27 Thus, the dipole−dipole interaction was the dominant mechanism of concentration quenching in this work. Thermal stability is a crucial index to evaluate the luminescence properties of phosphors.…”

A Zero-Thermal-Quenching Blue Phosphor for Sustainable and Human-Centric WLED Lighting

“…This uniquely smaller Stokes shift is particularly requisite for diminishing blue emission in human-centric WLED lighting. In addition, there is a sharp peak at 395 nm in the excitation spectrum, which may come from the 4f–4f transitions of Eu 3+ ions. , The XANES spectra of Eu-L 3 edge further certify that there exists a mixed valency in the NKMPO:0.04Eu 2+ phosphor (Figure e). In the XANES spectrum of the NKMPO:0.04Eu 2+ sample, two peaks at 6974 eV (Eu 2+ ) and 6982 eV (Eu 3+ ) can be observed, suggesting that some unreduced Eu 3+ exists in the NKMPO:0.04Eu 2+ phosphor.…”

Efficient Broadband Near‐Infrared Emission from Lead‐Free Halide Double Perovskite Single Crystal

“…Eu 2 + ions with 4f-5d transitions typically exhibit broad emission in the ultraviolet or visible spectral region, but in some specific systems, it can also show broadband NIR emission but until now no NIR Eu 2 + phosphor with emission extending to 1000 nm has been found. [5] A promising activator ion is Cr 3 + . Due to the wide excitation range, unique energy level structure and controllable broadband emission in weak crystal field coordination ( 4 T 2 !…”