Peripheral Decoration of Multi-Resonance Molecules as a Versatile Approach for Simultaneous Long-Wavelength and Narrowband Emission

High device efficiency and color-purity are the two essentials for high-quality organic light emitting diodes (OLEDs). Multi-resonance (MR) molecules show great potentials for high color-purity OLEDs due to their sharp emission bands. However, most MR molecules exhibit emission limited from deep-blue to green spectral region. Herein, through peripherally decorating MR emitter with electron donors, we demonstrated a new approach enabling the emission spectra of MR emitters red-shift while retaining narrowband emission. By manipulating the numbers and electron-donating abilities of the peripheries, the first narrowband yellow emitter with emission maxima of 562 nm and a full-width at half-maximum (FWHM) of 30 nm is realized. Highly efficient OLEDs with external quantum efficiency of over 24% and excellent color purity are fabricated by employing these newly developed MR molecules as emitters.