Emission Wavelength and Efficiency Tuning of Monoatomic Multiresonance Emitters Using a Multiresonance Manager

A molecular design strategy for managing the emission energy and energy levels while enhancing the emission efficiency of monoatomic multiresonance (MR) emitters based on a fused indolocarbazole (ICz) chromophore is developed by introducing a cyano (CN) unit as an MR manager. The MR manager intensifies the short-range charge transfer character of the fused ICz-based blue emitter, resulting in pure-blue emission with a narrow emission spectrum and an enhanced photoluminescence quantum yield. As a result, the CN MR manager-modified ICz derivative demonstrates a high external quantum efficiency (EQE) of 23.1%, a small full width at half maximum of 22 nm, and a pure-blue color coordinate of (0.142, 0.061). In addition, the introduction of the MR manager enables the fabrication of a blue phosphor-sensitized fluorescence device with an EQE of 24.6% while maintaining the narrow emission spectrum.