| As a new optoelectronic material,CsPbX3(X=Cl,Br,I)perovskite nanomaterials have attracted extensive attention in recent years.CsPbX3 perovskite nanostructures,especially CsPbBr3 quantum dots(QDS),have excellent properties such as high fluorescence quantum yield,narrow half-height width,and easy synthesis of fluorescence emission wavelength,which can be used in many fields,such as solar cells,light-emitting diodes,lasers,photodetectors,etc.Up to now,many synthetic methods have been developed,among which thermal injection synthesis and low temperature recrystallization are the main ones.The optical properties of the perovskite nanostructure CsPbX3 can be regulated by its size,morphology and composition,which have obvious quantum confining effect.However,their low lattice energy and ionic bond properties lead to structural instability.So far,many methods have been developed to improve its stability,including exchanging new ligands,silica coatings,polymer membranes and changing the ligands used in the experiments.As for perovskite nanostructures,their physical and chemical properties are still being explored to improve their structural stability and photoelectric conversion efficiency,and to expand their applications in photoelectric and other fields.In view of the main problems existing in the perovskite nanostructure of all inorganic CsPbX3(X=Cl,Br,I),some work has been done to improve its photoelectric properties and structural stability:1.Using high temperature heat injection method,we prepared CsPbBr3 nanostructures with different morphologies.PL spectroscopy shows that the emission peak location also changes,and the half-height width also varies with the change of morphology,indicating that morphology has a great influence on the size of perovskite nanocrystals.Besides,the UV-Vis spectra show that the spherical nanostructures have a small Stokes shift and a minimum energy loss during fluorescence.The time-resolved spectroscopy results show that the rod structure has long slow component lifetime and average lifetime,which is caused by the less exciton radiation recombination of the rod structure,the increase of exciton coincidence rate and the decrease of defect state transition.This indicates that the exciton recombination process can be adjusted by controlling the morphology of the nanomaterials.2.CsPbBr3/ZnO composite nanostructures were prepared by hydrothermal method.It was found that the CsPbBr3/ZnO composite nanostructures can effectively improve the electron-hole separation efficiency at the interface of photocatalytic reaction and inhibit the recombination of photogenerated electron hole pairs,significantly improve the photocatalytic activity of the material.Different composite ratios of CsPbBr3 and ZnO have different effects on the promotion of photocatalysis.It was found that the catalytic effect was the best when CsPbBr3:ZnO=1:1.5,because the amount of the absorption light was highest at the ratio.3.CsPbBr3 films decorated with ZnO nanoparticles were prepared on ITO,and the photoelectric properties of ITO/CsPbBr3:ZnO/Ag sandwich structure were studied.It has been found that the introduction of ZnO into the CsPbBr3 precursor solution can make the films have more uniform and compact crystalline particles,and ZnO nanoparticles can effectively promote the transmission of photogenerated carriers from the central absorption layer of CsPbBr3 to the transverse electrode,thus improving the photoelectric performance of the films.The results show that the potential height of CsPbBr3:ZnO films induced by ITO and Ag is about-44.5 meV,and the CsPbBr3:ZnO devices have obvious self-powered characteristics.Perovskite photodetector based on ZnO nanoparticles decorated with CsPbBr3 thin film.The introduction of ZnO into the solution of CsPbBr3 precursor can make the films have more uniform and compact crystalline particles.ZnO nanoparticles can effectively promote the transport of photogenerated charge carriers from the central absorption layer to the transverse electrode of CsPbBr3. |
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