Dipole-modified graphene with ultrahigh gas sensibility

This study reports the supramolecular assembly of functional graphene-based materials with ultrahigh gas sensing performances which are induced by charge transfer enhancement. Two typical Donor-pi-Accepter (D-pi-A) structure molecules 4-aminoquinoline (4AQ, mu = 3.17 Debye) and 4-hydroxyquinoline (4HQ, mu = 1.98 Debye), with different charge transfer enhancing effects, were selected to modify reduce oxide graphene (rGO) via supramolecular assembly. Notably, compared to the 4HQ-rGO, the 4AQ-rGO exhibits more significant increase of gas response (R-a/R-g = 3.79) toward 10 ppm NO2, which is ascribed to the larger dipole moment (mu) of 4AQ and hence the more intensive enhancing effect of charge transfer on the interface of rGO. Meanwhile, 4AQ-rGO sensors also reveal superior comprehensive gas sensing performances, including excellent gas sensing selectivity, linearity, repeatability and stability. It is believed that the present work demonstrates an effective supramolecular approach of modifying rGO with strong dipoles to significantly improve gas sensing properties of graphene-based materials. (C) 2018 Elsevier B.V. All rights reserved.