Synthesis, Characterization and Applications of All-Inorganic Perovskite Light-emitting Semiconducting Quantum Dots

The thrust of my master thesis is on the synthesis of zero-dimension all-inorganic perovskite quantum dots(CsPbX3, X = Cl, Br, I) nanomaterials by colloidal solution methodas luminescent materials for light emitting diode(LED)backlight display applications. In this study, we tuned halogen composition ratio and investigated particle size and band gap difference to explain the spectral shift. We expect to find a correlation of the spectral shift and therefore establish a general explain. We also controlled the Br/I ratio of CsPb(Br1-xIx)3 and analyzed their different optical properties. First, the 01C2 experiment station at the Synchrotron Radiation Research Center and Bruker D2 Phaser were used to measure X-ray powder diffraction patterns. We employed field emission electron microscopy to analyze the morphology of cubic quantum dots, and by turning the halogen composition corresponding with lattice spacing maintains regularity. We used Tauc plot to calculate the difference of band gap energy as shown by the spectral shift which we found to be caused by the different ratios of Br and I and not because of their particle size difference. Furthermore, we focused on this all-inorganic perovskite-type quantum dot which was applied for the first time for white light emitting diodes. With varying proportions of blue, green and red QD’s, a narrow, white light-emitting material was produced. Further, mesoporous silica particle loaded with perovskite-type quantum dots was also investigated to resolve problems ofion-exchange during LED packaging and thus, effectively enhance the material''s thermal and light stability. These novel nanocomposite perovskite-type quantum dots were successfully applied for LED devices.