Novel Cr³⁺ Doped Phosphors And Its Application In Bioanalysis

Long persistent materials is a kind of material which can store the optical radiation energy, and then through the slow release of stored energy in the form of visible light. For the research of rare earth long afterglow materials, it can be traced back to the middle of the 20 th century. Near infrared long persistent material as a new luminescence one, its type is still scarce. When it is applied in biological tissue, the NIR- LLP material has the following advantages:（1）. Excitation and emission in the near-infrared range can effectively penetrate through the biological tissue;（2）. Their Emission match well with the first biological window（650⁹50 nm） and the second biological window（1000¹400 nm）;（3）. These materials show unique long afterglow effect, and can be applied in real-time observation of the changing process of organism tissue.The purpose of this paper is searching novel materials with stable nature, efficient near infrared emission which could be used in biological analysis applications. The main contents are as follows:Ca₃Ga₂Ge₃O¹²:Cr³⁺ was synthesized by high temperature solid state reaction. The results show that Ca₃Ga₂Ge₃O¹²:Cr³⁺ calcined 8 h under temperature of 1150 °C has a strong red emission. Cr³⁺ doping content has a significant influence on the luminescence intensity of sample. After doping excessive Cr³⁺, the emission of the sample will be quenched. When Cr³⁺ content was 5%, the sample give the strongest fluorescence intensity. The spectral range of the sample was closed to the near infrared region, and the sample shows good afterglow effect, so that it is expected to be appliced in biological analysis.Cr³⁺ doping content has a significant influence on the luminescence intensity of sample. After doping excessive Cr³⁺, the emission of the sample will be quenched. When Cr³⁺ content was 5%, the sample give the strongest fluorescence intensity. The spectral range of the sample was closed to the near infrared region, and the sample shows good afterglow effect, so that it is expected to be appliced in biological analysis.Ca₃Ga₂Ge₃O¹²:Cr³⁺,Nd³⁺ was synthesized by high temperature solid state reaction. The results show that when Cr³⁺ content is fixed, Nd³⁺ doping content has a significant influence on the luminescence intensity of sample. Ca2.85Ga1.96Ge3O12:5%Cr³⁺,2%Nd³⁺ calcined 8 h under temperature of 1150 °C gives the strongest emission in the near infrared range. Emission intensity of Ca2.85Ga1.96Ge3O12:5%Cr³⁺,2%Nd³⁺ in near infrared range is 8th stronger than that in red range and is expected applied to biological living imaging. From the emission decay test, a afterglow time up to 11 h was determined. CaNb₂O₆:Cr³⁺ was synthesized by high temperature solid state reaction method. Under certain conditions,, luminous intensity of samples at ⁷00 nm increased with Cr³⁺ doping content. The luminescence of samples is not belonging to CaNb₂O₆ matrix or the characteristic emission of Cr³⁺. We proposed that the emission under 980 nm laser originated from the luminescence of high temperature objects. The photothermal effects of CaNb₂O₆:Cr³⁺ solution was test which indicated that CaNb₂O₆:Cr³⁺ can be good candidate for application in photothermal therapy.