▎ 摘　　要

We present a scalable and facile technique for noncovalent functionalization of graphene with 1-pyrenecarboxylic acid that exfoliates single-, few-, and multilayered graphene flakes into stable aqueous dispersions. The exfoliation mechanism is established using stringent control experiments and detailed characterization steps. Using the exfoliated graphene, we demonstrate highly sensitive and selective conductometric sensors (whose resistance rapidly changes > 10 000% in saturated ethanol vapor), and ultracapacitors with extremely high specific capacitance (similar to 120 F/g), power density (similar to 105 kW/kg), and energy density (similar to 9.2 Wh/kg).