Fluorene pendant-functionalization of poly(N-vinylcarbazole) as deep-blue fluorescent and host materials for polymer light-emitting diodes

& pi;-Electron coupling of pendant conjugated segment in & pi;-stacked semiconducting polymers always causes the formation of defect trapped sites and further quenched high-band excitons, which is harmful to the performance and stability of deep-blue polymer light-emitting diodes (PLEDs). Herein, considerate of "defect" carbazole (Cz) electromers in poly(N-vinylcarbazole) (PVK), a series of fluorene units are introduced into pendant segments (PVCz-DMeF, PVCz-FMeNPh and PVCz-DFMeNPh) to suppress the strong & pi;-electron coupling of pendant Cz units and enhance radiative transition toward fabricating sable PLEDs. Compared to PVCz-FMeNPh and PVCz-DFMeNPh, PVCz-DMeF spin-coated films show a relatively efficient deep-blue emission, completely similar to its single pendant chromophore, confirmed an extremely weak charge-transfer and electron coupling between adjacent pendant segments. Therefore, PLEDs based on PVCz-DMeF present stable and deep-blue emission with a high color purity (0.17, 0.08), associated with extremely weak defect emission at 60 0 & SIM;70 0 nm (induced by carbazole electromers). Finally, PLEDs based on PVCz-DMeF/F8BT blended films (1:1) also present the high maximum luminance ( L max ) of 6261 cd/m 2 and current efficiency ( CE max ) of 2.03 cd/A, confirmed slightly trapped sites formation. Therefore, precisely control the arrangement and packing model of pendant units in & pi;-stacked polymer is an essential prerequisite for building efficient and stable emitter for optoelectronic devices.& COPY; 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.