In this study, a new functional thiol with a pentafluorophenyl group was synthesized for the surface modification of CdSe quantum-dot floating layers; this was aimed at the fabrication of organic field-effect transistors (OFETs). The dipole moments and surface properties of the fluorinated thiols were used to control the transistor operations; these thiols acted as surface modifiers of the CdSe quantum-dot floating layers in the OFETs. Further, the new functional thiol exhibited a larger dipole moment than that of the commercial 2,3,4,5,6-pentafluorothiophenol. The OFET comprising the new functional thiol with the pentafluorophenyl group functioned as a normally ON transistor and exhibited bistable current states during nondestructive reading. In addition, it exhibited sensitive responses to electrical-only and light-only biases, which demonstrates its feasibility for light-responsive flash memory applications.