Excimer-based white electroluminescence from supramolecular bulk effects of dumbbell-shaped molecules via attractor-repulsor molecular design

Molecular attractor-repulsor design is one principle to precisely reorganize the active π-segments in organic semiconductors. Herein, we demonstrated two dumbbell-shaped pyrene derivatives, DSFXSOPy and DSFDBXPy, to examine the role of supramolecular interaction at bulky groups, together with the controlled DSFXPy. Bulky groups of SFXSO and SFDBX exhibits diverse supramolecular contacts of multiple C[sbnd]H⋯O hydrogen bonds and π-π stacking that were confirmed by single crystal X-ray diffraction. Their different photoluminescence profiles in films represent the robust evidences on their supramolecular steric hindrance effects on exciton behaviours. The single-component prototype devices based on DSFXSOPy and DSFDBXPy exhibited bright white light emission with the maximum current efficiency of 4.52 and 3.57 cd/A, respectively. Molecular attractor-repulsor design opens a way to tune molecular packing, film phase and morphology, as well as photo-physics and device performance.