▎ 摘　　要

We previously reported a light-sensing system composed of PSI (photosystem I) and graphene-FET (field effect transistor). The photoresponse could be observed only when surfactants and NaASC (sodium L-ascorbate) were added to the electrolyte. To clarify the properties of graphene-FET as a photosensor, the effect and mechanism of action of surfactants were investigated and discussed. Surfactants with longer alkyl chains can suppress undesired shifts in the Dirac point (charge neutrality point) induced by NaASC.