Abstract
We demonstrate organic light-emitting diodes (OLEDs) capable of yielding sunlightstyle illumination with various daylight chromaticities, whose color temperature (CT) covers those of the daylight at different times and regions. Besides having the disruptive characters like being plane-type and luminaire-ready, flexible, printable, thin, and light, the emissive spectrum of OLEDs closely resembles that of sunlight. The degree of sunlight spectrum resemblance is 63%, for example, for one high color rendering OLED, while 2% for a sodium lamp, 16% for a fluorescent tube, 49% for a light-emitting diode, and 72% for an incandescent bulb. By incorporating one hole-modulating layer (HML), a fluorescent sunlight-style OLED yields CT between 2300 and 7900 K, while the CT span can be further expanded between 2400 and 18000 K by using double HMLs. For a phosphorescent sunlight-style OLED, the CT spans between 1900 and 3100 K with a power efficiency of 17.6 lm/W at 1000 cd/m 2 . © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).