▎ 摘　　要

The use of vibrational sum-frequency spectroscopy (VSFS) to study transferred graphene, produced by chemical vapour deposition, is presented. The VSF spectrum shows a clear C-H stretching mode at similar to 2924 cm(-1), which is attributed to residue of the polymer used for the transfer. This makes VSFS a powerful tool to identify adsorbates and contaminants affecting the properties of graphene. (C) 2017 The Authors. Published by Elsevier Ltd.