| Perovskite has broad application prospects in solar cells,displays,light-emitting diodes and detectors due to its characteristics of long carrier diffusion distance,high luminous efficiency,tunable emission spectrum,high defect tolerance and solution processing.Especially in display and light-emitting diode applications,the high fluorescence quantum yield and narrow luminescence peak characteristics of perovskite endow great opportunity to wide color gamut display.However,compared with green light and red light emitting perovskite,blue light emitting perovskite develops slowly with low fluorescence quantum yield.Therefore,improving the luminous efficiency and stability of blue perovskite and solving the problem of lead toxicity play a key role in further improving the color gamut and developing electroluminescent white light display.Aiming at this frontier research direction,this paper utilize plasmon resonance to enhance the luminescence of highly stable blue emission lead halide perovskite,and fabricate stable,non-lead blue emission perovskite materials and electroluminescent light-emitting diode devices.The details are as follows:1.Polymer-coated perovskite quantum dot spinning film with the adjustment of halogen ratio were prepared in situ by electrospinning method suitable for industrial production.The resulting small size(3.4 nm)perovskite quantum dots are evenly distributed in the polymer and are not exposed,so the stability of the perovskite quantum dots is greatly improved under the protection of the polymer.On the other hand,silver nanoparticles of uniform size were prepared by controlling the reaction time,and their resonance absorption peaks matched well with the emission peaks of perovskite.Then,the polymer-coated silver nanoparticles spinning fiber layer was inserted into the middle of perovskite layer to obtain a three-layer composite membrane structure,so as to make full use of silver plasmas resonance to enhance perovskite fluorescence.Finally,by optimizing the concentration of silver nanoparticles,the fluorescence of perovskite was enhanced by about 4.8 times,and the reason for the increase of the optimal silver concentration was explained by the light field simulation.2.Lead-free blue emission 0D-Cs3Cu2I5 and yellow emission 1D-CsCu2I3 nanorods were synthesized by antisolvent method,and the transformation of 0D-Cs3Cu2I5 to 1D-CsCu2I3 was reported for the first time.The conversion is associated with the addition of ethanol,and when the volume of ethanol was 2.2 mL,the mixture showed nearly perfect white color coordinates(0.335,0.336),which indicate that 0D-Cs3Cu2I5 and 1D-CsCu2I3 mixture have great potential in the application of photoluminescence white light-emission diodes.Furthermore,we hypothesized and proved that the conversion mechanism was the stripping effect of ethanol to CsI in the process of ethanol-induced dissolution and recrystallization.3.Cs3Cu2I5 films with good thermal stability were prepared in situ by one-step spin-coating method,but the surface of the films was rough,porous and incomplete,which seriously affected their application in electroluminescent light-emitting diodes devices.Then,the morphology and luminescence properties of Cs3Cu2I5 films were optimized by introducing ligand and antisolvent processes.The effects of ligands of different concentrations,different carbon chain lengths and amino numbers on the morphology and luminescence properties of the films were investigated.The results showed that the surface of Cs3Cu2I5 films modified by low concentrations of MAI and octylamine ligands was smooth and uniform,and the luminescence properties were improved.In addition,the effects of 13 kinds of solvents on Cs3Cu2I5 films were also tested,and the results showed that ethyl acetate was the optimal inverse solvent,which greatly enhanced the uniform distribution of crystallinity and grain size.Finally,the optimized Cs3Cu2I5 film was combined with different transmission layers to prepare the electroluminescent white light emitting diode device.The maximum luminance of the device was 10 cd/m2. |
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