Photoluminescence And Nonlinear Optical Properties Of Perovskite Quantum Dots

Halide perovskites are emerging materials for optics and optoelectronic applications due to their superior optical properties and easy processing ability.Understanding the optical properties of these materials is essential for exploring their potential applications.This thesis focuses on the fabrication,polarized photoluminescence properties and nonlinear optical properties of perovskite quantum dots.The potential photonic applications of perovskite quantum dots are discussed.(1)Colloidal perovskite quantum dots are prepared by adapting the emulsion method.By mixing polystyrene and preformed perovskite quantum dots,bulk luminescent nanocomposites are prepared,showing good waterproofness and stability.This provides new material selection for light conversion applications,including remote white LED,holographic 3D display,etc.(2)The composite films of organic-inorganic hybrid perovskite quantum dots and polymer with polarized photoluminescence properties are prepared by applying the in-situ approach combined with mechanically stretching.The fluorescence quantum yield of the stretched films exceeds 80% and the polarization ratio is about 0.3.Spectroscopic studies show that the stretched films have no polarization excitation properties but exhibit significant polarization photoluminescence properties.By combining the theoretical analysis and material characterization,we propose that the polarized photoluminescence originates from the self-assembled ordered structure formed during the stretching process.This provides a simple and efficient method for preparing large area polarized light source without polarization excitation properties,which may have potential to improve the energy efficiency of LCD technology.(3)The third-order nonlinear optical properties of organic-inorganic hybrid and allinorganic perovskite quantum dots are studied by using the Z-scan technique.Experimental results show that the organic-inorganic hybrid perovskite quantum dot solution has selfdefocusing and two-photon absorption properties,while all-inorganic perovskite quantum dot solution has self-defocusing and saturated absorption properties.Similar to the corresponding quantum dots,the organic-inorganic hybrid perovskite single crystal has selfdefocusing and two-photon absorption properties.The results show that perovskite materials are nonlinear optical materials with excellent properties.