Preparation Of All-inorganic Perovskite Nanocrystals Via Polymer Nanoreactors And Their Stability

As an emerging luminescent material,all-inorganic perovskite nanocrystals have been widely used in the field of optoelectronic devices due to their excellent photoelectric properties.However,the external conditions including light,oxygen and moisture can trigger the degradation of all-inorganic perovskite nanocrystals,leading to poor stability.Therefore,it is of great significance to prepare all-inorganic perovskite nanocrystals with high stability.In this dissertation,two kinds of perovskite nanocrystals composites CsPbBr3 NCCs based on polymer nanoreactors were designed and prepared,and their stability was studied.The specific research contents are as follows:(1)Preparation of SiO2@CsPbBr3@PS/OA+OAm NCCs by using SiO2@PAA-bPS Janus nanosheets as the nanoreactor and their stability.First,SiO2@CH2Cl Janus nanosheets with silica hydroxyl group on one side and benzyl chloride group on the other side were prepared by using solid butanetetraol(C4H10O4)as a template,ethyl orthosilicate(TEOS)as the silicon source and 4-chloromethylphenyltrichlorosilane(CMPCS)as a modification reagent.The amphiphilic SiO2@PAA-b-PS Janus nanosheets were thus achieved by two-step ATRP polymerization and hydrolysis.Then,SiO2@CsPbBr3@PS NCCs were fabricated due to the interaction between the perovskite precursors and PAA by using the SiO2@PAA-b-PS Janus nanosheets as the nanoreactor.Upon the addition of organic ligands(i.e.,OA and OAm),SiO2@CsPbBr3@PS/OA+OAm NCCs with high PL intensity were obtained,and their stability against UV irraditation,heat,water,storage and organic solvents were studied.The results demonstrated that SiO2@CsPbBr3@PS/OA+OAm NCCs possessed remarkable high PL intensity and outstanding stability owing to the protection of hydrophobic PS and the effectively passivated surface with OA and OAm.Similarily,various highly luminescent and ultrastable CsPbBr3 NCCs can be created by adding other organic ligands such as APTES,APTMS,CTAB,MPC and NBS to SiO2@CsPbBr3@PS NCCs.Finally,the white light-emitting diode(WLED)with wide color gamutes and excellent stability were fabricated based on SiO2@CsPbBr3@PS/OA+OAm NCCs.(2)Preparation of PDVB@CsPbBr3@SiO2 NCCs by using PDVB-SO3H nanotubes as the nanoreactor and their stability.First,PDVB-SO3H nanotubes were dispersed in DMF,and PbBr2 and CsBr were then added,yielding a homogeneous precursor solution via stirring.Subsequently,the DMF precursor solution was quickly added to the toluene solution containing methyl orthosilicate(TMOS)and 3aminopropyltrimethoxysilane(APTMS),and CsPbBr3 NCs were in situ grown on the outer side of the nanotubes by the interaction between the sulfonic acid group(-SO3H)of PDVB-SO3H nanotubes and the precursors.A layer of SiO2 was concureently deposited on the surface of CsPbBr3 NCs via the hydrolysis of TMOS and APTMS,yielding PDVB@CsPbBr3@SiO2 NCCs.The fluorescence performance and stability of the resulting PDVB@CsPbBr3@SiO2 NCCs were scrutinized,and the results indicated that the PL intensity of PDVB@CsPbBr3@SiO2 NCCs was significantly higher than that of PDVB@CsPbBr3 NCCs.This phenomenon is a direct consequence of the formation of a protective SiO2 combine with a distinct passivation of APTMS.Additionally,the stability of PDVB@CsPbBr3@SiO2 NCCs were much better than that of the PDVB@CsPbBr3 NCCs and pure CsPbBr3 NCs owing to the double-layered protection of nanotubes and SiO2 layer.