Graphene Oxide/Hexylamine Superlattice Field‐Effect Biochemical Sensors

The bulky assembly of 2D materials is highly desired for macroscopic applications, but it is still challenging to access the exceptional properties of 2D materials owing to their spontaneous aggregation. Here, to facilitate the access of the field-effect sensing abilities of semiconducting 2D materials in bulk quantities, 3D hybrid superlattices of alternating graphene oxide (GO) and hexylamine molecular layers are constructed. Strikingly, the fabricated flexible GO/hexylamine superlattice exhibits a "V"-shaped ambipolar field-effect transfer characteristic under electrolyte gating, with exceptional sensing ability to pH value and DNA molecules in buffer solutions. In contrast, GO paper prepared by annealing the hybrid superlattices exhibits neither field-effect nor sensing responses to various analytes, highlighting the essential role that hexylamine plays in modulating the GO/hexylamine superlattice to enable a wider interlayer spacing for biomolecules transportation in the internal graphene layer. These achievements, along with stable electrical and sensing performance under mechanical stress of the 3D hybrid superlattices, highlight the unique potential of flexible graphene 3D hybrid superlattices for biochemical applications by overcoming multilayer aggregation.