Multifaceted Approach to White PIN OLEDs

Novaled is working on a number of different approaches to white light emitting OLEDs. They can be divided into four main groups: all fluorescent hybrid (fluorescent & phosphorescent) all phosphorescent and stacked white OLEDs. All four approaches are easily combined with the PIN OLED technology resulting in low operating voltage and very high power efficiency. These devices reach a power efficiency of more than 17 lm/W at this brightness without additional out-coupling enhancement methods. Using advanced fluorescent emitter systems, Novaled has been able to create white PIN OLEDs with the following characteristics (at 1,000 cd/m2): colour coordinates near the illuminant E life-time of > 15,000 h single emitter 17lm/W. White PIN OLEDs are suitable for innovative display as well as lighting applications. Current efficiency vs. luminance curve for a white bottom emission PIN OLED. The performance of the diode is 3.3V with 17 lm/W at 1,000 cd/m².   Using a stacked white OLED a new record has been reached for the power efficiency of a white OLED, obtaining 35 lm/W with colour coordinates of 0,43/0,44 and a CRI of 90 at a brightness of 1000 cd/m2. That same device structure thereby simultaneously shows a lifetime of more than 100,000 hours which is a major achievement for a future commercialization of the OLED technology for lighting applications. The efficiency of the device was measured using an integrating sphere using only the forward emission cone of the OLED device without attaching any lens or any other volume type luminaire to the OLED device. This is the only method to reliably predict power efficiency values for large area lighting tiles.