Polarization Optical Properties Of Perovskite Quantum Dots/Metal Nanocomposite Films

Perovskite quantum dot is a new class of optoelectronic semiconductor materials with tunable emission wavelengths,narrow fullwidth at half-maximum and high photoluminescence quantum yields.Due to the anisotropic of the structure,perovskite quantum dots self-assembled micro-nano structures can exhibit polarization luminescence without the use of additional polarizers,and have excellent potential for applications in optoelectronic devices.However,the ionic nature of these materials makes them sensitive to the environment,and prone to anion exchange and rapid dissociation in polar solvents.Thus,highly stable perovskite quantum dot has become one of the hot research topics in recent years.On the other hand,the polarization ratio of single-component perovskite films still needs to be improved,and the in-depth investigation of fluorescence stability and fluorescence properties of related composite structures is also an important issue facing their industrialization.Therefore,this thesis focuses on the preparation of highly stable,high photoluminescence quantum yield and polarization-sensitive perovskite quantum dot/metal nanostructure composite films.The influence of metal nanostructures on the polarization properties of perovskite quantum dots were discussed.The main results obtained are as follows.1)CsPbBr₃quantum dots modified with（3-aminopropyl）trioxysilane were obtained as colloidal solutions by high temperature thermal injection and their physical properties were analyzed.The results showed that the CsPbBr₃quantum dots were well crystalline,rectangular in shape,with a uniform size distribution and a particle size of about 39 nm.The obtained CsPbBr₃quantum dots showed stable green fluorescence under continuous UV illumination for 80 min.2)CsPbBr₃quantum dot films were obtained by a self-assembly method and passivated by introducing alumina on their surface by atomic layer deposition.The polarization ratio of the film is 0.03.The surface passivation was found to increase the luminescence intensity and improve the fluorescence stability of the films.3)CsPbBr₃quantum dots/Au nanorods and CsPbBr₃quantum dots/metal wire grid composite films were constructed,respectively.The results show that Au nanorods can improve the fluorescence intensity of CsPbBr₃quantum dots and increase the fluorescence polarization to 0.05.The polarization ratio of CsPbBr₃quantum dots can be increased to0.62 by combining Al metal wire grids with periodic structures.The introduction of the Al₂O₃passivation layer reduces the polarization ratio to 0.46,but effectively improves the fluorescence stability under light.