Preparation Of PMAA-b-PBA/Perovskite Composites

The perovskite material has a typical ABX3 perovskite cubic crystal structure,where A represents an organic amine cation(such as CH3NH3+),located at the vertex of the face-centered cubic lattice;B represents a metal cation(such as Pb+,Sn+),octahedral;X represents an anion,usually a halogen Cl-,Br-or I-,which is coordinated to B at the apex of the octahedron.Because of its wide range of raw materials,simple production process,controllable band gap,high absorption coefficient,and high carrier mobility,perovskite has been valued and researched by the researchers.However,organic-inorganic hybrid perovskite material is unstable,extremely sensitive to temperature and humidity,and will easily break down after being exposured to air,greatly limiting the application in the field of solar devices,new materials and others.Polymethylacrylic acid-block-polybutylacrylate(PMAA-b-PBA)is an amphiphilic biocompatible polyacrylate and can easily self-assemble into micelles in various solvents to protect and stabilize the inside material from external humidity environments.Therefore,PMAA-b-PBA with hydrophilic,negatively charged carboxyl groups and hydrophobic chain butyl acrylate was selected to modify the CH3NH3PbBr3 crystals so that the stability of prepared perovskites can be improved.The aim of this thesis is to synthesize the amphiphilic polyacrylate PMAA-b-PBA by reversible addition-fracture chain transfer polymerization(RAFT),and prepare PMMA-b-PBA/perovskite composites by using PMAA-b-PBA as the surfactant.The synthesized polymers and composites will be characterized via various methods,such as 1HNMR,GPC,SEM,XRD,TEM,UV-visible Spectrophotometer and Fluorescence spectrophotometer.The main contents of the study include the following four parts.Part 1: Preparation of RAFT chain transfer agent 4-cyanovaleric acid dithiobenzoic acid(CPADB).Part 2: Synthesis and Characterization of PMAA-b-PBA.Part 3: Fabrication and characterization of PMAA-b-PBA/Perovskite composites.Part 4: Exploring the stability of prepared composites.In summary,PMAA-b-PBA with different segments can be synthesized by RAFT method.The molecular structure of polymer can be controlled through the feed ratio.Using PMAA-b-PBA as the surfactant,PMAA-b-PBA/perovskite composites was successfully synthesized and the stability of the composites was improved.This prepared polymer/perovskite composite has a great potential for applications in biomedical and optical engineering.