Synthesis Of High-Stability Perovskite Quantum Dots And Their Optoelectronic Performance

All-inorganic CsPbX3(X=Cl,Br,I)perovskite quantum dots(PQDs)are expected to be used in lighting,backlight display,solar cell and other fields due to their narrow-band emission,adjustable emission colors with regulatable halide components and high photoluminescence quantum yield.However,due to the poor stability of perovskite quantum dots under high humidity,illumination and thermal radiation,as well as ion-exchange properties,the perovskite quantum dots will gradually decompose or phase transform with the extension of working time in LED applications,leading to rapid attenuation of LED luminous intensity.Moreover,due to the ion exchange between perovskite quantum dots of different halogen components,the position of emission peak of LED devices will be shifted during the working process,which will seriously affect the performance of LED devices.Therefore,the study of perovskite quantum dots with high luminescence stability is of great significance for the practical application of perovskite quantum dots.This paper focuses on how to improve the luminescence stability of perovskite quantum dots by constructing organic and inorganic perovskite quantum dot composite materials.The main research results of this paper are summarized as follows:(a)A novel strategy for preparation of CsPbBr3 perovskite quantum dots/ethylene acetate copolymer(EVA)composite film with high stability,flexibility and excellent luminescence performance was proposed.The key to the fabrication of the CsPbBr3 PQDs/EVA films was that both supersaturated recrystallization of CsPbBr3 PQDs and dissolution of EVA could be realized in toluene.The composite film shows stable green-lighting and flexible luminescence.The facile and ingenious strategy proposed in this chapter for fabricating long-term stable and flexible CsPbBr3 PQDs/EVA films will promote the practical use of CsPbX3 PQDs in lighting and flexible display application.(b)Two-dimensional hexahedral boron nitride(h-BN)nanosheets were used as inorganic protective matrix to form h-BN/CsPbBr3 perovskite quantum dot nanocomposites by heterogeneous nucleation at room temperature.The principle of luminescence stability of h-BN/CsPbBr3 perovskite quantum dot nanocomposites and protential application in lighting and display were all investigated.(c)We chose the α-Zr(HPO4)2·H2O(α-ZrP)nanosheets with high adsorptivity and selective adsorption performance as inorganic matrix to promote the stability of PQDs.High adsorptivity for the selective adsorption of Pb2+ and the good Cs+-ion exchange capability of the α-ZrP nanosheets promoted the heterogeneous nucleation-growth and effective anchoring of CsPbBr3 PQDs on α-ZrP surfaces.Consequently,the synthesized α-ZrP/CsPbBr3 composite exhibited superior green-emitting performance and significantly enhanced the humidity stability and thermal stability of PQDs.(d)Perovskite quantum dots were combined with PDMS membrane with pyramid microstructure as down-shift materials to improve the efficiency of silicon solar cells.Finally,the net efficiency of silicon solar cell was increased by 1.56%owing to the antireflective effect of PDMS film and down-shift of perovskite quantum dots.Moreover,after being stored in the air for 7 days,the composite film can still improve the efficiency of silicon solar cells,indicating that the composite film has good luminescence stability.