▎ 摘　　要

We introduce a concept to generate spin-polarized currents in graphene nanoribbons by using light radiation and a significant electron-electron interaction. For this purpose, we design a phototransistor based on the sawtoothlike graphene nanoribbons (SGNRs). The structures, with their intrinsic magnetic moments, have a narrow spin-dependent band around their Fermi energy that can enhance interband transitions and produce a spin photocurrent at room temperature without applying any magnetic field and without using any element. Interestingly, the changes in the size parameters and the gate voltage modify the magnitude and position of optical absorption peaks and optical spin polarization and the gate voltage individually switches the sign of the spin photocurrent. Finally, the fully spin-polarized photocurrent, the high quantum efficiency with a maximum of approximately 40%, the wide-wavelength-range operation from ultraviolet to infrared and optical spin-filtering effects, that are tunable with size and gate voltage, pave the way toward the improved design and performance of spin-optoelectronic devices based only on carbon atoms.