Flexible white thermally activated delayed fluorescence polymer with alkyl spacer and side‐chain encapsulation for efficient solution‐processed white organic light‐emitting diodes

Abstract White organic light‐emitting diodes based on doped systems face challenges such as phase separation, concentration quenching, and insufficient flexibility due to the intrinsic rigidity of small‐molecule emitters, making the realization of high‐performance flexible white organic light‐emitting devices (OLEDs) a persistent issue. Inspired by the “gemstone necklace” architecture, we developed a flexible alkyl spacers and side chain encapsulation strategy to synthesize a novel series of single‐component white‐light polymers, flexible spacer polymers namely PTF‐Qx. In these polymers, rigid red/blue thermally activated delayed fluorescence (TADF) units are alternately connected with flexible alkyl chains, which not only preserves the high‐efficiency luminescence of the TADF moieties but also greatly enhances solution processability and intrinsic flexibility. Moreover, the side‐chain encapsulation structure effectively suppresses exciton quenching caused by inter‐chain interactions, endowing the white‐light polymers with a high photoluminescence quantum yield of 76%. Non‐doped OLED devices fabricated from these polymers achieve efficient white‐light emission and excellent mechanical flexibility. Specifically, the rigid device exhibits a maximum external quantum efficiency of 15.66% with CIE coordinates of (0.36, 0.46), while the flexible white OLED has an EQE max of 6.98% and a luminance of 1226 cd m −2 . After 200 bending cycles, the flexible device retains 60% of its initial luminance, demonstrating remarkable mechanical durability. This work provides a feasible molecular design strategy for developing high‐performance, solution‐processable, and intrinsically flexible white‐light polymeric materials suitable for next‐generation white‐light devices.