Preparation And Properties Of Polyurethane/Perovskite Composites

Metal halide perovskites have attracted great attention because of their excellent characteristics including long carrier lifetime,high carrier mobility and tunable bandgap.They show broad applied potential in fields of solar cells,light emitting diodes,photodetectors and so on.They can be categorized from a componential perspective as organic-inorganic hybrid halide perovskites and all inorganic halide perovskites.Moreover,the size of perovskite crystals from millimeter sized single crystals to nanometer sized quantum dots.Perovskite single crystals are comparative stable owing to they have no grain boundaries.However,perovskite quantum dots are instable due to their large surface energy and ionic structure.In recent years,a lot of strategies can improve the quality of perovskite polycrystalline film.Chlorine can improve the quality of perovskite film and the performance of solar cells.However,the role of chlorine play in improving the quality of perovskite film is still unclear.Moreover,the report of chlorine and iodine mixed halide single crystals is very little.Few reports about the effect of chlorine in the growth of CH₃NH₃Pb I_3-xCl_x crystals.Therefore,it's important to prepare CH₃NH₃Pb I_3-xCl_x single crystals and explore the role of chlorine play in CH₃NH₃Pb I_3-xCl_x crystals growth.The instability of perovskite quantum dots is a bottleneck for their application,therefore many strategies are applied in improving their stability,using polymer to improve stability is a hot research topic.Nowadays,most researches using traditional polymer to prepare perovskite quantum dots-polymer composites to improve their stability.Smart polymer is a star material,and self healing polymer is a kind of smart polymer.In recent years,the combination of self healing polymer and perovskite is still less.Choosing smart materials to encapsulate quantum dots has great research potential,and provides the possibility for perovskite quantum dots to be applied in self healing flexible wearable devices.The main work of this article includes:(1)CH₃NH₃Pb I_3-xCl_x single crystals with different Cl/I ratio was prepared successfully.Moreover,the role of Cl play in the growth of mixed halide perovskite single crystals was explored.Cl can retard the nucleation and growth of perovskite crystals as an inhibitor due to the affinity of Cl and Pb.(2)First,CsPbBr₃ quantum dots was prepared by using hot injection method.Second,self healing polyurethane with transparency,self healing capability and superior mechanical properties was prepared to encapsulate CsPbBr₃ quantum dots.The mechanical properties of the obtained composite film is as good as the original self healing polyurethane.Moreover,the composite film with good optical properties also can heal scratches fast in moderate condition.In addition,the composite film has good stability in humid air condition and heat condition.