Band Gap Engineering of Nanoribbons Composed of Staggered Acenes Based on 2D Superatomic-Molecule Theory

Patterning graphene into nanoribbons is an efficient approach for tuning its band gap. The significant variation in band gaps among different typical types of nanoribbons highlights the importance of understanding their fundamental π-electron structures, which, however, remains systematically underexplored. Herein, acenes, building blocks of nanoribbons, are regarded as two-dimensional (2D) superatomic-molecules composed of ^◊O and ^◊F superatoms based on the 2D superatomic-molecule theory. The energy gap of acenes decreases with increasing length, resulting from the conjugation effect of P-type lone pairs (LPs) in SP-hybridized ^◊O superatom and ^◊F superatom. Several series of staggered acenes were constructed by introducing SP²-hybridized ^◊O superatoms to break the overall conjugation, thereby increasing the energy gap. These staggered acenes were further extended into nanoribbons, whose band gaps are widely tuned across a broad range from 0.00 to 2.45 eV. This work reveals the role of P-type LP conjugation in governing the electronic properties of nanoribbons and provides a strategic pathway for band gap engineering in graphene-based materials.