Improved viewing characteristics of red emission top-emitting organic light-emitting devices by integrating grating

An effective way to resolve the viewing-angle characteristics of microcavity red emission top-emitting organic light-emitting diodes (TOLEDs) by introducing grating and filling process into TOLEDs is demonstrated. From this approach, gradually changed cavity length can be obtained and the range of the resonant wavelength in these devices can be broadened. As a result, TOLEDs with grating exhibit a quasi-Lambertian emission pattern and have no color shift at different viewing angles. In addition, we can almost observe the same luminance and efficiency in TOLEDs with and without grating.