Preparation Of Bi,Cr Doped Broadband Near Infrared Luminescent Materials And Their Application In Spectral Detection

With the development of science and technology,the demand for near-infrared luminescent materials in the application fields of optical fiber communication and infrared spectrum detection is increasing.In particular,high-efficiency ultra-broadband near-infrared luminescent materials have become the bottleneck restricting the development of these fields.Bi,Cr doped materials have good broadband near-infrared luminescence properties,so they have attracted extensive attention.Bi doped glass can achieve ultra-broadband near-infrared luminescence in 1000-1700 nm band by selecting reasonable matrix glass and doping regulation,but the low luminous efficiency of Bi doped near-infrared luminescence glass limits the development of this kind of materials.In this paper,carbon-enhanced Bi broadband near-infrared luminescence was used,and then Yb³⁺/Cr³⁺co-doping was used to broaden its near-infrared luminescence,and it was used as a near-infrared light source in alcohol concentration detection.Considering that the luminescence intensity of Bi doped glass is still not high enough,resulting in insufficient optical signal in the detection of near-infrared spectroscopy,Cr³⁺doped Li Sc Si O₄ phosphors were selected to achieve ultra-broadband near-infrared luminescence.An attempt was made to use Li Sc_0.97Si O₄:0.03Cr³⁺phosphor as a light source in near-infrared spectral detection.The specific contents are as follows:1.The Bi doped broadband near-infrared luminescent glasses were prepared with a central wavelength of 1160 nm and a half-width of 160 nm.The broadband near-infrared emission intensity of Bi-doped borate glass can be significantly enhanced by introducing carbon into glass samples,and its broadband near-infrared emission originates from Bi⁺.Phase analysis showed that the addition of carbon did not change the microstructure of these Bi-doped borate glasses,which indicated that the carbon reduction effect could significantly increase the near-infrared luminescence centers of Bi.In the presence of reducing agent,the optimal doping concentration of Bi₂O₃ is about 0.06 mol%.In order to further broaden the near-infrared emission band of Bi-doped glass,the near-infrared spectral half-width of Bi-doped glass is broadened to a certain extent by co-doping Bi and Cr³⁺/Yb³⁺.Finally,the glass is used as a near-infrared light source,and a preliminary application attempt is made in the near-infrared spectrum detection.2.Li Sc_1-xSi O₄:x Cr³⁺broadband near-infrared phosphors have been prepared.Under the excitation of 450 nm light source,the luminescence range is from 1000 nm to 1700 nm,the luminescence center is around 1220 nm,and the full width at half maximum is about 250 nm.Li Sc_1-xSi O₄:x Cr³⁺phosphors have good absorption in the blue light region,and the broadband near-infrared luminescence originates from the⁴T₂（F）→⁴A₂（F）transition allowed by the spin of Cr³⁺ions.With the increase of Cr³⁺ion doping concentration,the near-infrared luminescence intensity of Li Sc_1-xSi O₄:x Cr³⁺phosphors gradually increased.When the Cr³⁺ion doping concentration was 0.03,the near-infrared luminescence intensity of the phosphors reached a peak value.Finally,the Li Sc_0.97Si O₄:0.03Cr³⁺phosphor is used as the near-infrared light source,and a preliminary application attempt is made in the near-infrared spectrum detection（ethanol gasoline content detection,alcohol concentration detection）,and the linear correlation coefficients were 0.9881 and 0.9947,respectively.It shows that Li Sc_1-xSi O₄:x Cr³⁺broadband near-infrared phosphors have potential application prospects in near-infrared spectral detection.