  We analyze electronic and phononic quantum transport through zigzag or chiral
graphene nanoribbons (GNRs) perforated with an array of nanopores. Since local
charge current profiles in these GNRs are peaked around their edges, drilling
nanopores in their interior does not affect such edge charge currents while
drastically reducing heat current carried by phonons in sufficiently long
wires. The combination of these two effects can yield highly efficient
thermoelectric devices with maximum $ZT \simeq 11$ at liquid nitrogen
temperature and $ZT \simeq 4$ at room temperature achieved in $\sim 1$ $\mu$m
long zigzag GNRs with nanopores of variable diameter and spacing between them.
Our analysis is based on the $\pi$-orbital tight-binding Hamiltonian with up to
third nearest-neighbor hopping for electronic subsystem, the empirical
fourth-nearest-neighbor model for phononic subsystem, and nonequilibrium Green
function formalism to study quantum transport in both of these models.
