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

Abstract 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.