Researchers from National Tsing Hua University in Taiwan have developed an organic light-emitting diode (OLEDs) with a range of color temperatures that fully covers those of daylight at different times and regions (2300K to 8200 K).
“The sunlight-style OLEDs demonstrated here have a relatively simple design, consisting of layers just a few nanometers thick of various color-emitting materials, as well as an electron-transporting layer and an electron-injection layer. As the researchers explain, changing the voltage varies the color temperature by increasing the number of electrons and holes transported between certain layers. For example, at 3 volts, the illumination is predominantly red, at 5.5 volts it turns to pure white, and at 9 volts becomes bluish white.”