Silicone-engineeredHoleTransportNetworkforHigh-resolutionandHigh-performanceOLEDMicrodisplay

Abstract

Organiclight-emittingdiodes(OLEDs)areoneofthemajordisplaytechnologiesduetotheirunprecedentedcolorpurity,fastresponsetime,thinformfactor,andexpandedcolorgamut.Duetotheseadvantages,OLEDsareapplicatedfromcommercializeddisplaystomicrodisplaysforvirtual,augmented,mutual,andextendedreality(VR/AR/MR/XR)devices.ForOLEDmicrodisplays,highpixelsperinch(PPI)aredemanded,however,thiscauseselectricalpixelcrosstalkwhereparasiticcurrentsflowthroughcommonhole-transportlayers(HTLs)betweenneighboringpixels,whichleadstopoorcolorgamutareaandcolorpurity.Photolithographyisthebestwaytodevelopmicro-patternsofHTLs.However,conventionalorganicHTLsarenotcompatiblewithphotolithographyduetotheirpoorphysico-chemicalendurance.Herein,wedemonstratedasilicone-integratedholetransportnetwork(SI-HTN)inwhichthesiliconemoietiesarehomogeneouslycrosslinkedwithholetransportmolecules.Micro-pixelationofSI-HTN(dimensiondownto1μm)weresuccessfullyachievedbythesilicone-engineeredlithography,whicheffectivelyreducedthepixel-crosstalk.Furthermore,SI-HTNshowedimprovedholeinjectioncapabilitywithefficientenergyalignment.Ournovelmaterialdesignforhigh-resolutionpixelationofHTLswillprovideguidanceforthenextgenerationofOLEDmicrodisplays.|유기발광다이오드(Organiclight-emittingdiode,OLED)는전례없는색채순도,빠른응답속도,확장된색상범위등의장점으로인해주요디스플레이기술중하나이다.이러한이점으로인해OLED는상용화된디스플레이부터가상현실(VR),증강현실(AR),혼합현실(MR),확장현실(XR)기기용마이크로디스플레이까지다양한분야에적용된다.OLED마이크로디스플레이를위해높은PPI(pixelperinch)가요구되는데,이로인해공통층인정공수송층(Holetransportlayer,HTL)을통해누설전류가흐르게되어이웃하는픽셀에영향을미쳐최종적으로색순도저하를일으킨다.따라서픽셀crosstalk현상을방지하기위해발광층뿐만아니라공통HTL도패터닝이요구된다.고해상도의균일한미세패턴을구현하기위해서는Reactiveionetching(RIE)을통한포토리소그래피패터닝이가장적합한기술이지만,유기물인HTL은포토리소그래피에사용되는다양한용매와etchinggas에대한resistance가낮아사용이제한된다. 본연구에서는실리콘도입형정공수송네트워크(Silicone-integratedholetransportnetwork,SI-HTN)을제시하고자한다.실리콘네트워크가도입된SI-HTN은높은내화학성및내식각성을보였으며,RIE기반포토리소그래피를적용하여고해상도패턴을구현하였다.해당기술을이용해픽셀화된SI-HTN을통해픽셀crosstalk을효과적으로감소시킬수있었다.더나아가,SI-HTN은효율적인에너지정렬과함께개선된정공주입능력을보였다.정공수송층의고해상도픽셀화를위한우리의시스템은차세대OLED마이크로디스플레이에적용될수있을것이라기대된다.