Fabrication and Characterization of Organic Light Emitting Diodes based on Printed Electronic Approaches

Abstract

The organic electronics have found their way into market with their devices like organic light emitting diodes and organic solar cells etc. Organic light emitting diodes are used in displays, large area lighting, advertising, information, and communications. Organic light emitting diodes have a number of advantages over the inorganic light emitting diodes. The organic light emitting diodes are fabricated using sustainable raw materials. Fabrication of organic light emitting diodes devices on R2R system can handle the future demands for mass production with low cost. Fabrication of OLEDs by printed electronics is achieved by using electrohydrodynamics spray deposition technique (ESD). Spin coating technique has disadvantages like the wastage of material, limitations on the size of substrate and difficulties in forming thin films with nanoscale thickness. These problems can be solved by using cheap and easy ESD technique operated at room temperature and pressure conditions. OLEDs are fabricated by employing conjugate polymers of PEDOT:PSS and MEH-PPV. ITO, aluminum, and silver are used as electrodes. The silver electrode is printed by a gravure offset printer installed on a R2R system. The web tension of R2R system is controlled for better printing. ZnO-graphene and CdSe/ZnS QDs are used to enhance the OLED performance. The thin films are characterized for their morphology, element analysis, optical analysis, and conductivity. Electrical and luminescence properties of organic light emitting diodes devices are also characterized. In the end, the spin coated samples are compared with ESD samples. The fabrication of solution based, flexible, OLEDs on a mass scale is made possible by the use of simple and cheap printed electronics approaches of ESD technique and gravure offset printing.