The invention relates to a method for functionalizing a conductive or semiconductor material (M) by covalent grafting of receptor molecules (R) to its surface, said method comprising the following steps: (i) applying, across the terminals of a source electrode and a drain electrode located on either side of the material (M), sufficient potential difference to thermally activate the material (M) with respect to the grafting reaction of the molecules (R); and (ii) placing the material (M) thus activated in contact with a liquid or gaseous medium containing receptor molecules (R), thereby obtaining a material (M) functionalized by covalently grafted receptor molecules (R).