Mn-doped Thick-shell Quantum Dots For UV Detection

As a semiconductor nanomaterial,quantum dots have unique physical and chemical properties,such as quantum size effect,surface effect,quantum tunnel effect,et al.,which makes them a good application prospects in biomedical and optoelectronic devices.And owing to luminescence tuning et al.,quantum dots also have wide applications in detection,display and solid-state lighting et al.Compared with nomal QDs,doped QDs have some special properties.For example,Mn-doped QDs can avoid self-absorption due to their large Stokes shift.The thick inorganic wide-bandgap shells can effectively passivate the defect states on the surface of QDs,with high photoluminescence quantum yields(PL QYs)and excellent photostability.Based on the good properties of doped thick core-shell quantum dots,the preparation of the quantum dots is mainly studied in this paper.And the QDs was applied in the UV detection system leter.At first,through the nucleation doping,ZnCdS:Mn/ZnS core-shell structure doped quantum dots with two ZnS monolayers were prepared by one-pot method.Related optical properties of the prepared QDs were measured to confirmed the usability in UV detection.The TEM images showed that the synthesized QDs have uniform size and good monodispersity.The fluorescence quantum yield was calculated to be 60%.Then,based on the structure above,a thick shell ZnCdS:Mn/ZnS quantum dot coated with more ZnS shells was prepared.By analyzing and summarizing the phenomena in the experiment,a method of low temperature injection and high temperature growth was used to produces the QDs.It finally made a fluorescence quantum yield of 38% and a of size 10 nm.Furthermore,the quantum dots@polymer films was prepared to apply in a UV detection system.It successfully collected the periodic response curve of the detector and the images as reported.Finally,in order to solve the problem of low utilization of light energy in the experiment due to the non-directionality of quantum dot fluorescence in QDs film,an optical cavity was designed.And effectiveness of the cavitywas verified through the simulation method.