1. Field of the Disclosure
The present disclosure relates to a conductive material for a display device and a method for fabricating an electrode, and particularly, to a conductive material having excellent electrical conductivity by using graphene applied to a flexible display device, a method for fabricating an electrode, and a display device having the same.
2. Background of the Disclosure
Recently, various types of flat display devices, capable of overcoming disadvantages of a cathode ray tube, e.g., a large weight and a massive volume, are being developed. Such flat display devices may include liquid crystal display (LCD) devices, field emission display devices, plasma display devices, organic electroluminescent display devices, etc.
Among such flat display devices, the plasma display device is being spotlighted as a display device the most suitable to a large screen, due to its simplified structure (i.e., light, thin, short and small structure) and fabrication processes. However, such plasma display device is disadvantageous in that light-emitting efficiency and brightness are low, and power consumption is large. On the other hand, the LCD device has disadvantages that a large screen is not easily implemented due to semiconductor processes, and power consumption is large due to a backlight unit. Further, the LCD device has disadvantages that an optical loss is great and a viewing angle is narrow due to optical devices such as a polarizing filter, a prism sheet and a diffusion plate.
The electroluminescent display device is distinguished from an inorganic electroluminescent display device according to a material of a light-emitting layer. The organic electroluminescent display device, a spontaneous light-emitting device which emits light spontaneously has advantages that a response speed is rapid, light-emitting efficiency is high, and brightness and a viewing angle are large. The inorganic electroluminescent display device has larger power consumption than the organic electroluminescent display device, cannot have high brightness, and cannot emit various colors of red, green and blue (RGB). On the other hand, the organic electroluminescent display device is driven at a low direct current voltage of several tens of voltages, has a rapid response speed and high brightness, and emits various colors of RGB. Accordingly, the organic electroluminescent display device is being actively researched.
The organic electroluminescent display device has a structure that an organic light-emitting layer is disposed between a cathode and an anode. Electrons from the anode are injected to the organic light-emitting layer, and holes from the cathode are injected to the organic light-emitting layer. As a result, excitons are generated in the organic light-emitting layer. As the excitons decay, light corresponding to an energy difference between a lowest unoccupied molecular orbital (LUMO) and a highest occupied molecular orbital (HOMO) of the organic light-emitting layer is generated. Then, the generated light is emitted to outside. The cathode is formed of a metallic material having a low work function, and the anode is formed of a transparent conductive material such as an Indium Tin Oxide (ITO) having a high work function.
However, the organic electroluminescent display device may have the following problems.
Firstly, the ITO used as an anode is a metallic oxide, which causes signal delay due to its large resistance. Further, such ITO is not suitable for an electrode of a flexible display device in recent years when the demand for a flexible organic electroluminescent display device increases drastically.