Synthesis And Application Of Water-soluble Multiple Quantum Dots And Quantum Dots Thin Films

In this article,water-soluble multiple quantum dots have been successfully synthesized via a facile and green method.These prepared QDs have the advantages of adjustable composition,large Stokes shift and low environmental toxicity,with huge market application foreground in the fields of photocatalysis and white Light Emitting Diode(LED).The main content of the thesis is as following:1.We have successfully demonstrated a facile and green method to aqueous synthesis of Cu-In-S/Zn S core/shell QDs used MPA and SC as dual stabilizing agent.The efficient photoluminescence(PL)emission can be tuned widely in the range of556-753 nm by controlling the composition of the QDs with the PL quantum yields(QYs)up to 20% after modifying with Zn S.The obtained Cu-In-S/Zn S core/shell QDs show excellent photocatalytic activities in the degradation of Rh B,after irradiating in sunlight for 15 min without stirring,the Eff can be up to 99%.Besides,the yellow-emitting core/shell QDs are used as wavelength converters for the fabrication of warm White-LEDs with warm white CCT(3431 K).2.Large-scale highly luminescent aqueous Ag-In-Zn-S quaternary quantum dots(4 L)have been directly synthesized via a one-pot method in an electric pressure cooker.This method is simple,green,and friend to the environment.The efficient PL emission can be tuned widely in the range of 507-743 nm by controlling the composition of the QDs with the PL QYs up to 65% after modifying with Zn S.The QDs' photocatalytic activities was realized by adding 400 m L of AIZS core QDs rude solution which contains 0.154 g QDs into 4 L Rh B(10 mg/L)aqueous solution.After irradiating in sunlight for 16 min without stirring,the Eff can be up to 98%.Besides,the red-emitting core/shell QDs are tested and used as wavelength converters for the fabrication of White-LEDs by covering the red-emitting QDs onto the surface of blue-Ga N chip.The fabricated white LED with cold white CCT(7073 K)shows good CRI(79)with a high luminous efficacy of 72.5 lm/W.3.We have successfully demonstrated a facile and green method to aqueous synthesis of highly luminescent gelatin-coated AIZS/ZnS core/shell QDs.The composition-dependent emission colors of AIZS/Zn S core/shell QDs can be tuned from blue to red(450–670nm),and the PLQY could reach as high as 38.3% after modifying with Zn S.Furthermore,as-fabricated three warm-white LEDs exhibit a high CRI of about 90,which indicate that as-prepared hybrid film are promising color converters for blue LED-pumped white LEDs.4.By using two natural macromolecules of chitosan and gelatin as film-forming substrates,glycerin as a plasticizer,as well as the operations of physical blending and casting filming,we have successfully prepared the highly transparent and flexible QDs/gelatin/ Chitosan hybrid film.And the effects on the transmittance,water solubility and mechanical properties of the film were Systematic investigated.This method is simple and does not involve complicated steps of exchanging or removing quantum dot ligands,which ensures the stability of the quantum dots.And the film has the advantages of gelatin-chitosan blend film and quantum dots which has wide application prospects in the field of LED.