▎ 摘　　要

A photochemical route for the facile synthesis of tunable bandgap graphene-based derivatives from graphene oxide (GO) through controlled laser irradiation in liquid phase is presented. The method is facile and fast, yielding these materials within 2 h and with excellent long-term stability. It makes use of photogenerated-solvated electrons that give rise to GO reduction, accompanied by preferential attachment of the desired functional unit, intentionally dispersed into the precursor GO solution. As a proof of concept, laser GO-ethylene-dinitro-benzoyl (LGO-EDNB) was photochemically synthesized and utilized as the electron acceptor material in organic bulk heterojunction solar cells (OSCs) with the poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] as the electron donor. The graphene derivatives are highly dispersible in organic solvents used in OSCs, while their energy levels can be readily tuned upon fine-tuning of the bandgap, which is directly related to the irradiation dose applied during the synthesis process. The utilization of LGO-EDNB with a band gap of 1.7 eV, and a resultant lowest unoccupied molecular orbital level of 4.1 eV, leads to maximum open-circuit voltage of 1.17 V and to power conversion efficiency (PCE) of 2.41%, which is the highest PCE for graphene-based electron acceptors to date.