Cr³⁺-Sphere Effect on the Whitlockite-Type NIR Phosphor Sr₉Sc(PO₄)₇ with High Heat Dissipation for Digital Medical Applications

Abstract

The analysis of human body composition and food composition requires high-efficiency broadband near-infrared (NIR) lighting sources to achieve a portable, appropriately sized equipment. Herein, we develop a whitlockite-type NIR phosphor Sr9Sc­(PO4)7:Cr3+ with an emission centered at 860 nm and full width at half-maximum of 147 nm. Due to the structural characteristics of the matrix, the 60 mol % Cr3+ substitution at the Sc3+ sites gives an internal quantum efficiency up to 56.5%. By replacing Sr with Ba and Ca, we observe a nontypical spectral shift phenomenon and discuss the influence of the second-sphere effect on octahedral Cr3+ ions. To evaluate the diagnostic application, we design a NIR ceramic device with a high optical power of 27.38 mW and high heat dissipation, which can decrease surface working temperature by nearly 50 °C for digital intraoral application. This study provides the research of the second-sphere coordination effect for selective octahedral sites such as Ca, Sr, and Ba coordinated by O atoms on a whitlockite-type crystal. Furthermore, the device promotes a nonionizing solution for detecting dental caries, tooth calcification, and diagnostic application.

Application of CAD/CAM Technology in Electrochemical Relief Design and Processing of Ceramic Art

“…ere is no essential difference between relief CNC machining programming and general CNC machining programming, so there are a lot of literature for reference. Chengdu University of Electronic Science and Technology takes the relief of the furniture [10] industry as the research object and carries out relief design and processing from the two-dimensional outline. e software is implemented based on the secondary development of AutoCAD and can only generate line-cutting and circular-cutting tool paths for 2D area milling.…”

Broadband Near-Infrared Luminescence in Garnet Y3Ga3MgSiO12: Cr3+ Phosphors

“…4−6 The newly developing NIR lightemitting diodes (LEDs) offer a long service life, high conversion efficiency, and small size, but the full width at half maximum (FWHM) of their emission bands is typically less than 50 nm, limiting their applications. 7,8 Inspired by white LEDs, NIR phosphor converted LEDs (NIR-pc-LEDs) provides a good solution to this problem, which possesses the advantages of compactness, low pollution, long lifetime, and competitive price. 9−12 Moreover, it can be combined with various NIR phosphors to satisfy the demands of potential fields.…”

“…Broadband near-infrared (NIR) light sources are playing an important role in brain imaging, palmprint identification, biological sensing, food composition analysis, etc., and are attracting increasing attention. − However, traditional infrared light sources (e.g., incandescent lamp and tungsten halogen lamp) suffer from the shortcomings of large size, low efficiency, and limited lifespan, which cannot meet the commercial application demands. − The newly developing NIR light-emitting diodes (LEDs) offer a long service life, high conversion efficiency, and small size, but the full width at half maximum (FWHM) of their emission bands is typically less than 50 nm, limiting their applications. , Inspired by white LEDs, NIR phosphor converted LEDs (NIR-pc-LEDs) provides a good solution to this problem, which possesses the advantages of compactness, low pollution, long lifetime, and competitive price. − Moreover, it can be combined with various NIR phosphors to satisfy the demands of potential fields. NIR phosphors act as an essential component of NIR-pc-LEDs.…”

Broadband emitting phosphor Sr6Sc2Al4O15:Cr3+ for near-infrared LEDs

“…NIR spectrometry is widely used in various analytical research fields, including agriculture, 1 the food industry, 2 noninvasive medical testing, 3 and so forth. [4][5][6][7] When the NIR spectrum becomes broader, more structures and composition information of organics can thus be detected.…”