1 January 2011 Optimization of the efficacy and angle dependence of emission of top-emissive organic light-emitting diodes on metal foils
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J. of Photonics for Energy, 1(1), 011024 (2011). doi:10.1117/1.3590937
Abstract
We have investigated how to optimize the efficacy and angle dependence of emission of top-emissive organic light-emitting diodes (OLEDs) based on metal foil substrates with the aim of creating efficient flexible devices for lighting and signage applications. By systematically varying the device architecture we were able to tune the optical microcavity which exists within the device structure and observe the change in performance. We paid particular attention to the effects of the metal foil roughness. We have seen that by changing the layer thickness of the poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) [PEDOT:PSS] in the device, and the substrate reflectivity and roughness we can obtain efficacies not too far from those achieved for standard bottom-emissive devices on glass substrates made with the same emitter. The angle dependence of luminance can be tuned from pointing in the forward direction via Lambertian to having a maximum at around 65°, and we have used optical modeling to help us find the optimum device structure. We conclude that (rough) metal foils are a realistic possibility for making flexible OLEDs and have demonstrated large area (up to 12 cm × 12 cm), thin film encapsulated, flexible devices.
Harmen Rooms, Dorothee Hermes, Stephan Harkema, Cristina Tanase, Ton van Mol, Paul W. M. Blom, Joanne Wilson, "Optimization of the efficacy and angle dependence of emission of top-emissive organic light-emitting diodes on metal foils," Journal of Photonics for Energy 1(1), 011024 (1 January 2011). http://dx.doi.org/10.1117/1.3590937
Submission: Received ; Accepted
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KEYWORDS
Organic light emitting diodes

Metals

Reflectivity

Optical microcavities

Reflection

Polymers

Light scattering

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