Performance Control And Application Of CsPbX₃?X=Cl,Br,I?/Ag₂Se Semiconductor Quantum Dots

In recent years,as an ideal fluorescent nanomaterial,semiconductor quantum dots?QDs?have attracted much attention due to their adjustable emission wavelength,stable optical performance,narrow-band fluorescence emission,and long luminescence lifetime.With the development of society,the problem of environmental damage is becoming more and more serious.Traditional incandescent light sources have a problem of wasting energy due to the required high temperature.Compared with the traditional incandescent lamps,white light-emitting diodes?WLEDs?have become a new generation of illumination sources with lower power consumption,smaller size,longer life and environmental friendliness.The unique optical properties of semiconductor QDs enable him to become a fluorescent material for light-emitting diodes.In addition,QDs exhibit desirable optical properties and good biocompatibility are also widely used for in vivo bioimaging.Based on this,this paper selects pure inorganic perovskite QDs as phosphors to prepare WLEDs and study their optical properties.The CsPb_xMn_1-xCl₃ is then prepared by doping Mn²⁺to reduce toxic Pb²⁺,and the optical properties were investigated.In addition,silver selenide QDs are selected as fluorescent probes for in vivo imaging,brain and abdominal vascular imaging.The main research contents of this thesis are as follows:1.Red CsPb?I₂Br₁?,green CsPbBr₃,and blue CsPb(Br_1.5Cl_1.5)phosphors were successfully prepared by a thermal injection method via changing the doping ratio of Cl,Br,and I.The structure and shape were characterized,which demonstrated that the sample presented mainly cubic phase structure,high uniformity and excellent optical properties.Finally,the explored trichromatic phosphors were coated onto the UV diode to construct the warm WLEDs device.2.The CsPb_xMn_1-xCl₃ phosphors were synthesized by a hot injection method to reduce the proportion of the toxic Pb²⁺content in pure CsPbCl₃host by doping Mn²⁺.The results show that the optical properties of the synthesized CsPb_xMn_1-xCl₃ samples are different under different conditions,indicating the doping induced luminescence color control.3.We used bovine serum albumin as the soft template to synthesize the ultra-small Ag₂Se QDs with a size of about 3 nm by oil bath method.The optical properties of Ag₂Se QDs synthesized at different temperatures were investigated.The results show that the samples have excellent second near infrared?NIR-II?emissions under the excitation of 808 nm laser.At the same time,the explored Ag₂Se QDs were further used as nanoprobes for in vivo NIR-II imaging of Kunming mice,and non-invasive brain and abdominal vascular imaging.