White organic light-emitting diodes with extremely low turn-on voltage at 1.5 V

Abstract

Reducing the applied voltage of white organic light-emitting diodes (OLEDs) is crucial for lowering power consumption in commercial displays. However, achieving white emission at low voltages remains a significant challenge, with turn-on voltages typically exceeding 2.5 V. In this study, we report a white OLED with an exceptionally low turn-on voltage of less than 1.5 V. We utilized a triplet–triplet annihilation (TTA) upconversion (UC) process that can produce high-energy blue emission at a small-applied voltage. White-color emission was achieved by incorporating sky-blue and yellow dopants into a blue UC-OLED to control the white color by energy transfer rates from the TTA host to the two dopants. Finally, we demonstrated the white UC-OLED that could be operated by a single 1.5 V battery.