Preparation And Application Of Three Long Afterglow Materials

Long persistence materials（PLNPs）have the property of long-lasting luminescence after being irradiated by a short-lived external excitation light source（such as ultraviolet,visible light,X-ray,etc.）.At present,long afterglow materials mainly include metal-based long-afterglow materials and non-metal-based long-afterglow materials.Using the time-resolved properties of near-infrared metal-based long afterglow materials to overcome the interference of scattered light,the signal-to-noise ratio is high,and it has a wide range of applications in the biological field.Carbon dots（CDs）are a new class of non-metallic carbon-based materials with longer-lived luminescence and longer stokes shift properties at room temperature.Since the phosphorescence of triplet excitons is easily inactivated by the non-radiative inactivation of dissolved oxygen in water,the phosphorescence of long afterglow carbon dots is usually easily quenched in water dispersants.Therefore,it is necessary to find an effective method to prepare water-soluble phosphorescent microspheres.The main research contents of this paper are as follows:（1）An MB probe using a long afterglow nanomaterial ZnGa₂O₄:Cr³⁺（PLNPs）as an energy donor was constructed and applied to the homogeneous analysis of miR21 in biological samples.Oil-soluble near-infrared emitting PLNPs were prepared by LLS three-phase method,and water-soluble polyacrylic acid-modified PLNPs were obtained by surface ligand exchange.to construct long-persistence MB probes.In the presence of miR21,the long afterglow emission of the probe gradually recovered with the increase of target concentration,thus establishing a method for quantitative detection of miR21.Based on the time-gated advantage of PLNPs,the long-persistence molecular beacon probe exhibits strong anti-interference ability in biological samples,can quantitatively detect miR21 at a concentration of 0.1-10 n M,and can detect miR21 in serum and cell extracts.level for quantitative analysis.（2）A microwave preparation technology of B/N doped long afterglow carbon dots was developed,and its application in anti-counterfeiting and information encryption was carried out.It is found that the B,N-CDs prepared by microwave method using melamine and 3-carboxyphenylboronic acid as raw materials have a phosphorescence lifetime of 237 ms,a cyan afterglow phenomenon of at least 8 s can be observed with the naked eye,and the emission wavelength of the afterglow is 505 nm.Through characterization methods such as XPS,FT-IR,TEM,etc.,it can be verified that the successful doping of N and B elements effectively promotes the ISC process between the first excited singlet state and the triplet state,and realizes the phosphorescence emission.Furthermore,B,N-CDs with excellent room-temperature phosphorescence properties have been successfully applied in anti-counterfeiting and information encryption.（3）It is proposed that the green raw material diatom（Algae round seaweed）can be refluxed in NaOH solution to generate Na₂SiO₃,and then reacted in HAC solution to generate H₄SiO₄.After calcining at high temperature,a solid CDs@SiO₂long afterglow material can be prepared.When the optimum calcination temperature is 400℃,the phosphorescence lifetime is at most 156 ms,and the cyan afterglow phenomenon can be observed for at least 5s with the naked eye.And CDs@SiO₂prepared water-soluble CDs@SiO₂phosphorescent microspheres in weak alkaline environment.Through analysis,the CDs generated from diatoms were successfully embedded into the stable silicon-oxygen nanostructures built by SiO₂during the calcination process.This method successfully realized the phosphorescence of the carbon dots in the aqueous phase.