▎ 摘　　要

Covalent functionalization of graphene offers a great chance to broaden its further applications. Here we demonstrate the site-selective chlorination of graphene through a laser-induced in situ decomposition of 3-5 nm AgCl nanoparticles fabricated on the graphene surface by pulsed laser deposition. The chlorination process, using the laser coupled on the Raman instrument, can be monitored by in situ Raman spectroscopy. A structural disorder, which resulted from a change from sp(2) to sp(3) configuration due to the covalent chlorination, increases the electrical resistance of graphene by over two orders of magnitude. We believe this chlorination process from in situ decomposition of AgCl may open up a new avenue for graphene modification and bandgap modulation.