Synergetic Interface And Morphology Modification To Achieve Highly Efficient Solution-Processed Sky-Blue Organic Light-emitting Diodes

Thermally activated delayed fluorescence(TADF)materials can theoretically achieve 100% exciton utilization,and are composed of noble metal-free organic materials,and are expected to become the next generation of new display materials.The key factor restricting the further development of TADF materials is the problem of low efficiency of blue-ray material devices.Therefore,in order to improve the efficiency of blue light TADF organic light-emitting diodes(OLEDs),this thesis mainly carried out the following aspects of research: using 10-(4-(4,6-diphenyl-1,3,5-triazine-2-keto)(Spiro AC-TRZ)high-efficiency sky blue TADF material as a luminescent material,by adjusting the interface and the luminescent layer material,to improve the luminescent layer film quality,to achieve an excellent energy level structure and carrier balance,achieved a very high Efficient blue light device.The main research contents of this article are as follows.(1)In this thesis,the luminescent material of sipro AC-TRZ as a light-emitting guest material under different device structures are studied,and a PVK layer is added to balance the carrier transport by using a high-temperature cross-linking method before the lightemitting layer.The PVK layers of different thicknesses and the doping ratio of the host and the guest were compared,and a high-efficiency sky blue TADF organic electroluminescent device was prepared.(2)Based on(1),we improved the thin film morphology of the light-emitting layer by doping a small amount of polymer in the light-emitting layer.Due to the strong molecular aggregation,most small molecules show poor film-forming properties during the preparation of the solution-process.We added a small amount of PVK to the lightemitting layer to improve the film formation of small-molecule light-emitting materials in the light-emitting layer,and make the film of the light-emitting layer more dense and smooth.PVK was selected as the light-emitting layer dopant because of its excellent filmforming properties and good solubility in chlorobenzene.However,because PVK as the host material results in low lifetime and high driving voltage of the device,and it is difficult to overcome its triplet energy and other reasons,it is not suitable for highconcentration doping ratios.By doping PVK with different proportions,The photoelectric properties and surface morphology of the device were tested,and it was concluded that when the doping ratio of PVK was 10%,the optimized performance of the device was the best.This thesis contains 51 figures,9 tables,and 67 references.