Large room-temperature magnetic field effect of photoluminescence in few-layer metal-free semiconductor fluorographene

Organic semiconducting materials with a large magnetic field effect on photoluminescence (MFE PL ) are expected to be superior in innovative opto-spintronics. However, the magnitude of positive MFE PL has remained relatively weak. While fluorinated graphene may give the favorable conditions for elevating the MFE PL performance triggered by smaller spin-exchange interaction within intermolecular charge-transfer (CT) states, and it's MFE PL has not been investigated. Here, we report a substantial positive MFE PL , featuring a magnitude of 32.5% at room temperature, in few-layer fluorographene (FG) dispersed in hexanol under an applied magnetic field of 840 mT. Remarkably, the MFE PL remains available at 17.65% when the field is reduced to 176 mT. Additionally, a large positive MFE PL of 14.36% is observed in the FG:BCP composite film. We demonstrate that MFE PL can be effectively tuned by controlling the FG layer number and the dielectric constant of the organic solvent used for dispersion. These findings reveal that the intermolecular charge-transfer (CT) states in donor-acceptor composites are contributors to the improved MFE PL .