The latest milestone in WOLED technology for OLED TV and IT displays: Enhancing efficiency, color gamut, and longevity

This study introduces recent innovative progress in white organic light emitting diode (WOLED) technology for premium OLED TV and IT displays. By fabricating a four-stack tandem device consisting of red, first blue, green, and second blue devices in sequence from the anode, we could achieve a current efficiency of the WOLED up to 134 cd/A at 10 mA/cm², resulting in enhanced efficiency for red, green, and blue subpixels after transmitting color filters. The new OLED TV implementing the four-stack WOLED technology reached luminance levels of 2,900, 1,000, and 400 nit at the average picture level (APL) of 3%, 25%, and 100%, respectively, and a flash peak luminance of 4,000 nit. Since the four-stack device uses red, green, and blue dopants of saturated color, eliminating yellow green (YG) dopant used for our previous WOLEDs, its color gamut in the Broadcasting service Television (BT)-2020 standard was widen up to 83%. We will explain how to enhance the efficiency and the lifetime in terms of device structure and materials.