Graphene Top Electrode for OLED Sheet Resistance Reduction

The patent employs a composite electrode structure consisting of a transparent conductive oxide layer (such as ITO or IZO) combined with a metal layer (such as silver or aluminum). This composite structure leverages the high transparency of the oxide layer and the high conductivity of the metal layer, achieving both optical transparency and electrical conductivity simultaneously. The multi-layer composite design resolves the contradiction by combining materials with complementary properties rather than relying on a single material that cannot satisfy both requirements.

The patent applies different materials with specific properties to different regions or layers of the electrode structure. The transparent conductive oxide provides optical transparency in the regions where light transmission is critical, while the metal layer provides conductivity in regions where electrical performance is prioritized. This localized assignment of material properties allows the electrode to simultaneously achieve both transparency and conductivity without compromise.

The patent introduces an auxiliary electrode layer (such as a buffer layer or protective layer) before depositing the transparent conductive oxide on the organic light-emitting layer. This preliminary action protects the organic layer from damage during the oxide deposition process. The auxiliary layer acts as a barrier that prevents direct contact between the oxide deposition process and the sensitive organic material, thereby maintaining organic layer integrity while still achieving the desired optical and electrical properties.

The patent uses an intermediary layer (auxiliary electrode layer) between the transparent conductive oxide and the organic light-emitting layer. This intermediary layer serves as a mediator that allows the oxide to be deposited without directly damaging the organic layer. The intermediary layer transfers or distributes the stress and potential damage from the deposition process, protecting the organic layer while enabling the formation of the transparent conductive oxide electrode.

The patent uses a composite structure combining transparent conductive oxide layers with different compositions and thicknesses, along with metal layers, to achieve the desired balance. By optimizing the thickness and composition of each layer in the composite structure, the patent achieves both high optical transmittance and sufficient electrical conductivity. The composite design allows each material to contribute its superior property while compensating for the weaknesses of other materials.

The patent optimizes various parameters of the electrode structure, including layer thickness, composition ratios, and deposition conditions, to achieve the optimal balance between transparency and conductivity. By carefully controlling parameters such as the thickness of the transparent conductive oxide layer and the composition of the composite structure, the patent achieves high optical transmittance while maintaining adequate electrical conductivity for device operation.