Fabrication And Nonlinear Optical Properties Of Ternary Quantum Dots/PMMA Composite

Due to the unique physical effects including surface effect,quantum confinement effect,quantum tunneling effect,quantum size effect and nonlinear effect,quantum dots have potential application in the fields of light,electricity,magnetic and biology,etc.On the basis of the synthesis of Cd_xZn_1-xSe and CdSe_xS_1-x ternary quantum dots,this thesis studies the fabrication and non-linear optical properties of the organic composite of Cd_x Zn_1-xSe tertiary quantum dot/PMMA and CdSe_xS_1-x-x tertiary quantum dot/PMMA.The main achievements are as follows:1.By using modified“one-pot boiling”synthesis method,Cd_xZn_1-xSe di-cation ternary quantum dots and CdSe_xS_1-x-x di-anion ternary quantum dots were successfully prepared,respectively.The as-prepared quantum dots,with a mean grain size of less than 5mm,are characterized by good crystallization,monodispersity,and outstanding non-linear optical properties,which pave the way for the further fabrication of composites.2.The synthesis technique of ternary quantum dot/polymethyl methacrylate composite was investigated in detail.With methy methacrylate?MMA?used as the monomer and benzoyl peroxide?BPO?as the initiator,di-cation ternary quantum dot Cd_xZn_1-xSe/PMMA and di-anion ternary quantum dot CdSe_xS_1-x/PMMA composite,with coloury appearance,good transparency and high mechanical strength,were successfully fabricated by a modified solution“blending method”.3.The non-linear optical property of di-cation ternary quantum dot Cd_xZn_1-xSe/PMMA and their laser protection property were investigated.The results demonstrated that the composite had good non-linear optical property;the non-linear absorbance and the non-linear refractive index of Cd_0.75Zn_0.25Se/PMMA reached as high as 7.90×10^-8 m/W and-0.99×10^-8 esu respectively.In particular,this material had obvious optical limiting effect,which is of importance for further investigation in the field of laser protection.4.The non-linear optical property and laser protection property of di-anion ternary quantum dot CdSe_xS_1-x/PMMA were investigated.The results showed that the non-linear absorbance and the non-linear refractive index of CdSe_0.75S_0.25/PMMA reached-0.99×10^-7m/W and-6.91×10^-8 esu,respectively.