Precise Synthesis of Conjugated Polymers Grafted with Red/Green TADF Units via Postfunctionalization for Single-Molecule White Electroluminescence

Generally, single-molecule white-emitting polymers (SMWEPs) are synthesized by the direct polymerization of functional monomers. Herein, we designed conjugated polymers PCFTN-X (X = 0.5, 1, 3, 5, or 10) by grafting red/green TADF units onto the backbone via alkyl linkers. This structural design balances the charge transport of the conjugated backbone with the independent photophysical properties of the TADF units on the side chains. PCFTN-X was synthesized via Suzuki polymerization and post-Click reaction, ensuring good reproducibility and tunable red/green ratios. The nondoped device based on PCFTN-3 achieved stable white emission with CIE coordinates of (0.34, 0.38), a low turn-on voltage (Von) of 3.4 V, a maximum external quantum efficiency (EQEmax) of 10.23%, and a maximum luminance (Lmax) of 3264 cd m–2. This design and synthesis strategy can be extended to other optoelectronic polymers.