Jiacheng Ma, Ze-Lin Zhu, Jihai Shang, Shanshan Qi, Junjin Chen, Nan Chen, Jingsheng Miao, Chuluo Yang, Xiaojun Yin
Cyclobutadiene fusion reconstructs frontier-orbital symmetry in polycyclic aromatic hydrocarbons, while two-dimensional π-extension amplifies aromaticity gradients and suppresses vibronic broadening. The resulting emitter exhibits an 8.6 nanometre full width at half maximum, near-unity photoluminescence quantum yield, weakened shoulder emission, and approximately 20% external quantum efficiency in vacuum-deposited hyperfluorescence organic light-emitting diodes.