Cr3+-doped near-infrared(NIR)luminescent materials have attracted significant attention due to their high quantum efficiency,tunable broadband emission,and strong absorption in the blue spectral range.The emission range of Cr3+can be adjusted through crystal field engineering,but conventional cation substitution limits this turning to the NIR I-region(<1 000 nm).In the field of biomedical imaging,the NIR Ⅱ region offers lower absorption,tissue scattering,and autofluorescence,allowing for deeper tissue penetration and minimally or non-invasive imaging.In this study,a series of Cr3+doped NIR phosphor materials BaSc1-xO2F:x Cr3+(x=0.001-0.01),were synthesized by high-temperature solid-state reaction method based on Ba2Sc2O5 oxides with anionic F substitution.The synthesized samples exhibited a cubic perovskite structure as confirmed by XRD patterns and tolerance factor calculations.The Cr ions were verified to be in the+3 valence state using diffuse reflectance spectroscopy(DRS)and X-ray photoelectron spectroscopy(XPS).Electron paramagnetic resonance(EPR)was employed to analyze the crystal environment around Cr3+.The samples displayed broadband NIR emission in the wavelength range of 700-1400 nm,with a full width at half maximum(FWHM)of up to 250 nm and an emission center around 1 040 nm,effectively covering the NIR Ⅱ region.The study demonstrates the feasibility of modulating the crystal field strength by anion doping based on the relationship between internal structure and optical properties.Due to the overlap between the photoluminescence excitation(PLE)and photoluminescence(PL)spectra(700-850 nm),increasing doping concentration led to partial reabsorption and a significant redshift of the emission center.The absorption peaks of the phosphor roughly match with blue LED chips,indicating commercial potential.This work provides excellent broadband near-infrared light source materials for NIR Ⅱ region phosphor-converted LEDs(pc-LEDs)in biomedical imaging applications.
关键词
宽带近红外光/高温固相法/荧光粉/Cr3+/钙钛矿结构/阴离子F修饰/晶体场强度/近红外Ⅱ区
Key words
broadband NIR emission/high-temperature solid-state reaction/phosphor/Cr3+/perovskite structure/anion F doping/crystal field strength/NIR Ⅱ region
万方数据