Preparation And Characterization Of Inorganic Perovskite Quantum Dots

Inorganic perovskite CsPbX₃?X=Cl,Br,I?quantum dots?QDs?have outstanding properties such as high absorption coefficient,tunable narrow emission spectrum and high photoluminescence?PL?efficiency,which attracts intense research interest.Inorganic perovskite nanomaterials were expected to find its potential application in photoelectric devices such as light-emitting diodes,dispalys and solar cells.However,perovskite CsPbX₃ QDs is highly sensitive to water,which easliy lead its crystal structure to decompose.The poor stability of these perovskite materials also restricts its wide application.This thesis starts from the synthesis of the highly luminescent pervoskite QDs by optimizing the preparation process.To improve the stability problem of the perovskite QDs,the silicon alkoxide as well as silane coupling agents were used to modify the surface.The main results of this study are detailed as follows:?1?Synthesis and characterization of perovskite CsPbX₃ QDsPerovskite QDs were prepared by general thermal injection method.Efforts were made on investigating the role of surfactants as well as the influence of precursor Cs/Br ratio on the luminescent efficiency and morphology of QDs.Through optimizing the synthesis process,monodisperse highly luminescent perovskite QDs were finally obtained.?2?Synthesis of Mn-Doped Perovskite CsPbX₃ QDsAdding Mn precursors during the preparation process,Mn-Doped Perovskite QDs were obtained.The influence of reaction temperature and the Mn/Pb ratio on the PL properties of Mn-doped QDs were investigated.The results show higher reaction temperature and larger amount of Mn precursor promote Mn-doping in the perovskite QDs,which enhance the PL efficiency without changing the structure of perovskite QDs.?3?Surface modification of perovskite CsPbX₃ QDsUsing tetramethoxysilane?TMOS?and 3-aminopropyltrimethoxysilane?APS?,the surface of perovskite QDs were modified.Adjusting the mixing time and amount of silicon alkoxide,the stability of QDs were greatly improved to be dispersed into polar solvent of ethanol.