Preparation Of Inorganic Perovskite Quantum Dots And Research On LED Application

In recent years,light-emitting diode,as a device widely used in solid-state lighting and display,has attracted great attention from researchers for its stability,color tunability and low energy consumption.At present,the most promising solid-state light source is the phosphor-conversion LED device.The phosphor with different emission wavelength can be excited through the blue-violet light emission source to fabricate the lighting device with adjustable wavelength.Furthermore,the white light emitting device can be fabricated by changing the ratio of blue-violet light emission source and phosphor.All-inorganic perovskite quantum dots?PeQDs?are a kind of nano-fluorescence material with excellent luminescence properties,which can be used as fluorescence conversion material to construct LED devices with various emission wavelength.In this paper,all-inorganic perovskite quantum dots?PeQDs?were prepared and two kinds of p-GaN/n-ZnO/CsPbBr₃ QDs heterojunction LEDs were prepared by growing ZnO nano-plates on GaN by hydrothermal method and vapor phase transport method,respectively.Ulteriorly,a white luminescent LED device was constructed by spinning green luminescent CsPbBr₃-PMAO and red luminescent CsPbBr₁I₂-PMAO onto the commercial blue light chip.With the aid of TEM,SEM,PL spectrum,UV-Vis spectrum and EL spectrum,the morphology,structure,fluorescence characteristics of QDs and luminous performance of LED devices were analyzed.The following main conclusions are obtained:?1?The ZnO nano-wall structure with good crystallization performance can be grown by hydrothermal method after controlling the reaction time,reaction temperature and other parameters.Besides,the all-inorganic perovskite CsPbBr₃ QDs synthesized by hot injection method has high fluorescence quantum yield?PLQY?and good fluorescence stability when dispersed in non-polar solvents.The final preparation of p-GaN/n-ZnO/CsPbBr₃ QDs heterojunction LED showed dual-band emission characteristics.?2?The vapor phase transportt method can successfully grow ZnO nano-plates aligned perpendicular to GaN,which have a large specific surface area and good optical waveguide and light scattering characteristics.The dual-band emitting heterojunction LED was prepared after a layer of CsPbBr₃ QDs was spun.The as-fabricated LED with an opening voltage of about 2.8V showed good luminescence characteristics,operational feasibility and practical value.The blue light emitted by the ZnO/GaN heterojunction LED consists of three different sub-bands centered at377 nm,398 nm,and 423 nm,while the CsPbBr₃ QDs produces the green light excited by the light from heterojunction.?3?All-inorganic perovskite quantum dots were coated by polymer PMAO to improve its stability,and the green glowing CsPbBr₃-PMAO and red glowing CsPbBr₁I₂-PMAO were synthesized.The fluorescence performance of the QDs was excellent,and the stability in the air was enhanced.The tri-chrominance primary white LED produced bright white light with color coordinates of?0.314,0.291?,showing good electroluminescence performance.