Narrowband pure-green emitters based on naphthalene-fused meta-positioned double boron framework

Pure organic boron/nitrogen (B/N)-containing multiple resonance (MR) materials are very attractive emitters for the fabrication of narrowband organic light-emitting diodes (OLEDs). Recently, v-DABNA, having a meta-positioned double boron framework, has gained prominent recognition for its unprecedented narrowband blue emission at 468 nm. Therefore, creating narrowband green emitters by modification this particular framework is regarded as a promising endeavor. Herein, we showcase two narrowband emitters named BN-NAP and BN-ANAP, emitting green light at 511 and 518 nm with small full-width at half-maximum (FWHM) of 26 and 20 nm, respectively. Their synthesis by the fusion of the meta-positioned double boron framework with two naphthalene moieties is proven to be a simple yet effective tactic to red-shift emissions while keeping small FWHM. Utilizing BN-ANAP as the emitter, high-performance narrowband pure-green OLEDs have been assembled, achieving a maximum external quantum efficiency (EQEmax) as high as 21.0