Improvement Of Electrode Performance Of Organic Light-emitting Diode Using Atomic Layer Deposition

Organic Light-Emitting Diode?OLED?have attracted wide attention in recent years for their advantages such as self-luminescence,high color saturation,high contrast,large viewing angle,fast response speed,and flexibility.Transparent Conductive Electrode?TCE?,as a key component of OLED,has attracted extensive attention of researchers all over the world.Transparent conductive oxide?TCO?electrodes represented by tin-doped indium oxide?Sn:In2O3,ITO?are widely used in semiconductor lighting,photovoltaics,touch panels,and flat panel displays.The main problems that still exist in TCO are:1.Electrode Electrical and optical performance characteristics is not good,and it is difficult to increase in the further;2.poor mechanical properties limit its application in flexible devices.In order to develop transparent electrodes with excellent transparency,conductivity,stability,and flexibility,a great deal of research has been focusing on graphene,ultra-thin metals,carbon nanotubes,and conductive polymers.Among them,ultra-thin metal has excellent electrical conductivity and light transmittance,and has received widespread attention in recent years.The problems faced by ultrathin metal electrodes are mainly the problems of preparation process and stability:the performance and roughness of the ultra-thin metal electrodes prepared by magnetron sputtering limit their further development,and the ultra-thin metal electrode prepared by the physical vapor deposition method has excellent performance,but has poor stability and is extremely easily oxidized.In this paper,ultra-thin metal is selected as the research object,trying to develop a transparent electrode with excellent translucency,conductivity,stability and flexibility.Atomic layer deposition?ALD?is based on the self-restricted saturated chemisorption reaction principle and will be the preferred process for the preparation of conformal ultrathin films in the future.In this paper,the low-temperature deposition of copper metal thin film electrodes was studied using the ALD technique with[Cu-?dmap?₂]?dmap 4-dimethylaminopyridine?and diethyl zinc?Et ₂Zn?as the reaction sources.result:The matching of the work function between the electrode and the organic layer will also affect the balance of carrier injection.Therefore,the performance of the electrode directly affects the efficiency and stability of the OLED device,and improving the performance of the electrode layer has always been one of the research focuses of the OLED.Compared to traditional vacuum physical and chemical methods,atomic layer deposition technology is based on the reaction principle of self-limited saturated chemical adsorption on the surface,and will be the preferred process for the preparation of conformal ultra-thin films in the future.In this paper,atomic layer deposition technique was used to study the low temperature deposition of copper thin film electrodes using[Cu-?dmap?2]?dmap4-dimethylaminopyridine?and diethyl zinc?Et ₂Zn?as the reaction source.The following result:?1?For the first time,we used a pyridinium-based copper precursor for atomic layer deposition to prepare ultra-thin copper thin-film metal electrodes.When the deposition temperature was 110°C,the atomic layer deposition cycle was copper precursor 0.1s,diethylzinc 0.06s,Flushing for 60 s,a highly pure,smooth,continuous,highly conformal copper thin film electrode was obtained on a rigid substrate glass and a flexible substrate PET at a deposition rate of 0.022 nm/cycle.When the Cu film thickness is 10 nm,the copper film electrode shows an excellent surface morphology with an average surface roughness of 0.62±0.03 nm,a sheet square resistance of 10.2?sq^-1,and a transmittance of 74%at a wavelength of 550 nm.What's more,the flexible ultra-thin copper anode prepared by this method still maintains good electrical conductivity under a radius of curvature of 2 mm,and after bending 100times and its electrical conductivity does not change much.?2?The rigid OLED device based on the metal anode using glass as a substrate and the flexible OLED device using polyethylene terephthalate?PET?have excellent performance,and the highest brightness and current efficiency of the OLED devices are comparable.Its excellent device efficiency and brightness seem promising as a substitute for ITO in flexible electronic devices.