Continuous Ultra-Broadband Near-Infrared Sc_2O_3-Based Nanophosphor Realized by Spectral Bridge of Cr~(3+)-Yb~(3+)-Cr~(4+) for Multiple Optical Applications

摘要

Cr~（3+）-activated near-infrared (NIR) phosphors are one of the most influentialcandidates for the new generation of intelligent NIR phosphor-convertedlight-emitting diode (pc-LED) light sources. For spectral analysis, the broaderthe spectrum, the more useful information it contains. Herein,ultra-broadband Cr-activated Sc_2O_3 nanophosphors, which exhibit NIRultra-broadband from 650 to 1600 nm, are developed by the sol–gel method.This ultra-broadband emission originates from the presence of Cr~（3+） and Cr~（4+）,two luminescent centers confirmed by diffuse reflection spectra, electronparamagnetic resonance, time-resolved photoluminescence spectra, andtemperature-dependent emission spectra. The nanophosphor exhibitsexcellent temperature-sensing performance with SA = 4.102 K?1 and SR =1.855 K?1. Co-doping Yb~（3+） into Sc_2O_3 nanophosphors builds theCr~（3+）-Yb~（3+）-Cr~（4+） model to bridge the spectral gap located at 1000 nm, forminga continuous NIR ultra-broadband spectrum ranging from 650 to 1600 nm forthe first time. Moreover, the introduction of Yb3+ improves the thermalstability of nanophosphors from 29.49 to 50.65 at 150 °C. The NIRtransmission spectra of water, ethanol, and peanut oil demonstrate thatSc_2O_3:Cr~（3+）-Yb~（3+）-Cr~（4+） NIR nanophosphors favor potential applications inspectral analysis. The construction of a Cr~（3+）-Yb~（3+）-Cr~（4+） spectral bridge forrealizing NIR ultra-broadband phosphors based on cheap blue LEDs providesnovel and effective insights.