Silica-based Room Temperature Phosphorescent Materials Based On Carbon Dots

Room temperature phosphorescent?RTP?materials refers to luminescent materials which could emit phosphorescence at room temperature.Owing to their inherent property of afterglow emitting,RTP materials hold wide potential applications in fields like anti-counterfeiting,information encryption and sense.Nowadays,available RTP materials could be divided into metal-containing RTP materials and metal-free RTP materials.Metal-containing RTP materials hold several disadvantages,such as poisonousness and high-cost preparation,it's the trend of the times to develop high performance metal-free RTP materials.However,existing metal-free RTP materials possess shortcomings,like poor stability and narrow range of the color of their afterglow,which seriously limited their applications.The phosphorescence of existing metal-free RTP materials would be easily quenched by oxygen and water,thus make their optical property changeful in actual application,which would severely limit their service life.Therefore,it's of great significance to develop metal-free RTP materials with high stable phosphorescence.Besides,the afterglow color range of existing metal-free RTP materials is quite narrow,and mostly distributed in the range from yellow to green,leaving blue and red unexplored.Hence,expand the color range of metal-free RTP materials is one of the main research interests of the development of RTP materials.In this paper,silica microspheres with super-stable RTP and silica microparticles with deep blue RTP were prepared based on the basic process of synthetizing carbon dots via hydrothermal method,together with the prepare method of silica.Principally,there are two sections as follows.1.Carbonized polymer dots?CPDs?embedded SiO₂ microspheres?CPDs/SiO₂Ms?with high stable RTP property is synthesized through one-pot hydrothermal method,by using Tetraethyl orthosilicate?TEOS?and ethylenediamine?EDA?as raw materials.This material could not only maintain its RTP property after immerging in various solvents?water,strong acid,strong base and oxidizers?for 24 hours,but also maintain its RTP color and lifetime after exposing to oxygen atmosphere for 2 hours.What's more,after 200^oC treatment,the RTP property could maintain.After analyzing,it's proposed that this material was silica microspheres with CPDs inside.CPDs was the luminescent centers of this material,while silica microspheres act as protection shield.2.Silica microparticles with deep blue RTP afterglow was prepared through one-pot hydrothermal method,by using 3-Aaminopropyltriethoxysilane?KH550?as raw material.Its afterglow peak was at 430 nm.The primary part of this material was silica microparticles,with carbon dots on the surface.After analyzing,it's proposed that CDs was the luminescent centers.The intrinsic structure of KH550 make the CDs was connected to the silica microparticles via short covalent bonds,and this make the energy gap between singlet and triplet state low enough,resulting in the deep-blue afterglow emitting of the product.Above all,this paper realized materials with super stable RTP property and deep blue RTP afterglow were realized by combining silica and carbon dots,and the carbon dots acted as the luminescent centers.This paper is instructive for preparing high stable RTP materials and further expand the afterglow color range of RTP materials.