Light extraction for a doubly resonant cavity organic LED: the RC2LED

Peter Vandersteegen, Saso Mladenovski, Volker van Elsbergen, Georg Gartner, Peter Bienstman, Kristiaan Neyts, Roel Baets, Zakya H. Kafafi, Franky So
2007 Organic Light Emitting Materials and Devices XI  
The RC 2 LED is a substrate emitting OLED which has three additional interference layers between the ITO electrode and the glass substrate. This creates two resonant optical cavities. The RC 2 LED has 2 resonant optical cavities. The first cavity is also present in regular devices and is formed by metal/organic layers/ITO. The second cavity is formed by 3 additional layers: a high refractive index layer (Nb 2 O 5 ), a low refractive index layer (SiO 2 ) and a high refractive index layer (Nb 2 O
more » ... index layer (Nb 2 O 5 ). The additional layers introduce a strong wavelength dependent improvement of the extraction efficiency compared to the OLED without the additional layers. Our simulations show an improvement of the extraction efficiency of over 70% over a wavelength range of 75 nm compared to an OLED without the 3 layers. Light extraction is worse compared to the reference OLED for wavelengths outside this wavelength range. This improvement has been experimentally verified for a green OLED with an emission between 500nm and 650 nm. A numerical study shows a relative improvement of 10% for the luminous power efficiency of a 3 color white OLED with the additional layers. The emitted white corresponds with the light emitted by illuminant A. The WOLED has been composed of a fluorescent blue emitter, green and red phosphorescent emitters.
doi:10.1117/12.732524 fatcat:fg3nup3rwba2hdcg7wmlox37by