  The charge photogeneration process in organic molecules is investigated by a
quantum heat engine model, in which two molecules are modeled by a two-spin
system sandwiched between two bosonic baths at their own temperatures. The two
baths represent the photon emission source and the phonon environment,
respectively. We utilize the time-dependent density matrix renormalization
group algorithm to investigate the ultrafast quantum thermodynamical processes
of the model. We find that the transient energy flow through the two spins
behaves a two-stage effect: The first stage shows a coherent dynamics which
represents the ultrafast delocalization and dissociation of the charge-transfer
state, and in the second stage a steady current is establish. The
photo-to-charge conversion is highly efficient with the maximum efficiency
being $93\%$ with optimized model parameters. The survival entanglement between
the two spins is found to be mostly responsible for the hyper efficiency.
