Color-Tunable TADF Conjugated Polymers Toward Voltage-Regulating White OLEDs for Intelligent Lighting

Color-tunable luminescent polymers are highly desirable materials for meeting the daily needs of humans in terms of circadian rhythm, yet they are rarely reported. Herein, a feasible approach is developed for color-tunable thermally activated delayed fluorescence (TADF) conjugated polymers by incorporating green and red TADF units into blue fluorescent polymeric backbone. The solution-processed OLEDs based on the synthesized polymers exhibit high-efficiency red emission with a maximum external quantum efficiency (EQEmax) of 26.1% under low voltage (6 V). With a slight increase in voltage, warm white emission with EQEmax of 23.9%, color rendering index (CRI) of 76 and low corelated color temperature (CCT) of 1700 K is obtained. These results represent the highest efficiencies among the red and warm white OLEDs based on TADF polymers, respectively. Intriguingly, under higher voltage (10 V), warm white emission with high CRI of 87, CCT of 3216 K, and luminance of over 5300 cd m-2 is accessible. This work provides a promising approach for intelligent lighting by voltage-regulating white OLEDs. A series of thermally activated delayed fluorescence (TADF) polymers are developed by embedding green and red TADF units into a blue fluorescent polymeric backbone. Their devices demonstrate voltage-regulating color-tunability with emission ranging from red (EQEmax of 26.1%) to warm white (EQEmax of 23.9%).image