▎ 摘　　要

We report temperature-dependent ultrafast hot carrier relaxation in graphene oxide (GO). At all temperatures in the range from similar to 6 to 400 K, the time evolution of the photoexcited relaxation reveals a three-component recovery, among which the initial two components are signature time constants of graphene. We experimentally confirm that the slowest third relaxation component (tau(3)) is not related to the radiative recombination of the carriers, rather due to the carrier scattering from defects present in GO. We observe that tau(1), and tau 3 are nearly independent of the sample temperature, while tau(2) linearly increases with the sample temperature providing the main bottleneck in carrier relaxation. The latter is due to the accumulation of excess number of hot phonons in the decay cascade with increasing lattice temperature. From this behavior, we have estimated the electron-phonon coupling strength in GO.