Top emitting organic light emitting diodes with opaque metal grid electrodes by transfer technique

The opaque metal grid electrodes are introduced to fabricate top emitting organic light emitting diodes (TOLEDs) through metal transfer technique. To transmit the lights, micrometer-sized patterns of aluminum (Al) were utilized as top cathodes in OLEDs and Al mirrors were also deposited at the other side of transparent substrates to reflect the lights emitted at the bottom sides. Although the only 50% of brightness compared to bottom emitting OLEDs (BOLEDs) could be achieved theoretically, the actual devices showed more than 70% based on the compressive effects during the metal transfer process. Since the resolution of human eyes recognizes these micrometer-sized grid structures as one pixel, TOLEDs can be simply fabricated without significant loss of efficiency.