Preparation And Application Of Perovskite Quantum Dot Ink Based On Inkjet Printing

Metal halide perovskites hold significant promise for low-cost,solution processed thin-film opto-electronic devices due to their high quantum fluorescence efficiency,excellent color purity,low-cost precursor materials and full visible waveband tunability.In particular,CsPbX₃?X=Cl,Br,I?perovskite quantum dots have more advantages in luminescent properties than traditional quantum dots.So it is used as light-emitting layer material in perovskite light-emitting diodes?LEDs?.There are many ways to deposit the luminescent layer.In laboratory,spin coating and other methods are often used to fabricate devices,which will waste materials.Ink jet printing overcomes this disadvantage.As a high-precision deposition method,it has the following advantages:low cost,non-contact,no mask,high resolution,suitable for automatic manufacturing,no waste of materials,etc.However,there are still some difficulties in the ink-jet printing of perovskite quantum dot devices,such as the regulation of the uniformity of the light-emitting layer film,which inevitably requires the use of perovskite quantum dot ink in the process of ink-jet printing.The original works are given as follows:1.Cesium carbonate?Cs₂CO₃?,lead bromide?PbBr₂?,1-octadecene?ODE?,oleic acid?OA?,and oleylamine?OLA?were used as raw materials to synthesize CsPbBr₃perovskite quantum dots by thermal injection.The CsPbBr₃ quantum dots were characterized by X-ray diffraction?XRD?,transmission electron microscopy?TEM?,ocean optical system and spectrophotometer.The results show that the quantum dots have good cubic phase,single dispersion and uniform particle size.2.CsPbBr₃ quantum dots are separately dispersed in toluene?TOL?and dodecane?DOE?to form single solvent quantum dot ink.Characterized the surface tension,viscosity,and contact angle of the single-solvent inks.Inkjet printing microarrays and lines on poly-?9-vinylcarbazole??PVK?layer using single-solvent inks.The surface morphology of the dried microarrays and lines was characterized by fluorescence microscopy and surface profiler.The cause about formation of coffee ring,and the effects of viscosity,surface tension,evaporation rate,contact angle on surface morphology are discussed.3.Two kinds of single-solvent quantum dot inks were mixed to obtain double-solvent quantum dot inks with different volume ratios of DOE and TOL.The surface tension and viscosity of double-solvent inks are characterized.Double-solvent inks with different volume ratio of DOE and TOL were printed on PVK layer to form microarrays,and the surface morphology were characterized after drying.The results show that when the volume ratio of DOE to TOL in the double-solvent ink is 6:4,there is no coffee ring on the surface of the microarrays,and the roughness is low.The reason for this phenomenon is discussed.Quantitative analysis of the coffee ring phenomenon after printing with different double-solvent inks.The competitive relationship between Marangoni flow and capillary flow are explored.The Z value is used to discuss the stability of the optimal double-solvent ink droplets.Patterned on the PVK layer using the optimal ink,and there was no coffee ring on the pattern surface after drying.Finally,PeLED were fabricated using the optimal ink.