Narrowband Fluorescent Emitters Based on BN‐Doped Polycyclic Aromatic Hydrocarbons for Efficient and Stable Organic Light‐Emitting Diodes.

Organic light‐emitting diodes (OLEDs) using conventional fluorescent emitters are currently attracting considerable interests due to outstanding stability and abundant raw materials. To construct high‐performance narrowband fluorophores to satisfy requirements of ultra‐high‐definition displays, a strategy fusing multi‐resonance BN‐doped moieties to naphthalene is proposed to construct two novel narrowband fluorophores. Green Na−sBN and red Na−dBN, manifest narrow full‐width at half‐maxima of 31 nm, near‐unity photoluminescence quantum yields and molecular horizontal dipole ratios above 90 %. Their OLEDs exhibit the state‐of‐the‐art performances including high external quantum efficiencies (EQE), ultra‐low efficiency roll‐off and long operational lifetimes. The Na−sBN‐based device achieves EQE as high as 28.8 % and remains 19.8 % even at luminance of 100,000 cd m−2, and Na−dBN‐based device acquires a record‐high EQE of 25.2 % among all red OLEDs using pure fluorescent emitters. [ABSTRACT FROM AUTHOR]