Purification And Stability Of CdSe/ZnS Quantum Dots

Quantum dots(QDs)are a kind of semiconductor nanocrystals which possess high quantum yield,wide excitation spectrum,narrow emission spectrum and good optical stability.QDs have been widely used in solar cells,photoelectric detectors,light-emitting diodes and solar energy converters due to their good optical properties.Currently QDs display technology is a hot spot of research.The current QDs liquid crystal display(Q-LCD)is a backlight display technology using quantum dots as light-conversion materials.In this technology,QDs optical devices need to maintain their initial optical properties under long-term high temperature,high humidity and blue light irradiation conditions.Therefore,higher requirements for optical stability of quantum dot materials are put forward.In this paper,the blue light QDs films and blue light aging chamber were built to test QDs processed by different purification methods.The QDs surface ligands were also characterized.The influence of purification reagents on the stability of QDs was further preliminarily investigated.The main research work contents are listed as follows:1.Quantum dots with uniform particle size and good crystallinity and fluorescent properties were synthesized by thermal injection method and regulation of the composition of elements,surface ligands and reaction time.Their average particle size was about 9nm,fluorescence emission wavelength was 530 nm with the half-peak width of 26 nm,and relative fluorescence quantum yield was 83%.2.QDs were purified by precipitation-resolving method.A purification method beneficial to enhance the optical properties of QDs was explored using the purification system of alkanes/alcohols and regulation of the polarity and proportion of purification reagents.The influence of purification reagents on the optical stability of QDs was preliminarily evaluated by characterization of their surface ligands.