Excitonic effects,
arising from the Coulomb interactions between
photogenerated electrons and holes, dominate the optical excitation
properties of semiconductors, whereas their influences on photocatalytic
processes have seldom been discussed. In view of the competitive generation
of excitons and hot carriers, exciton dissociation is proposed as
an alternative strategy for hot-carrier harvesting in photocatalysts.
Herein, by taking heptazine-based melon as an example, we verified
that enhanced hot-carrier generation could be obtained in semicrystalline
polymeric photocatalysts, which is ascribed to the accelerated exciton
dissociation at the abundant order−disorder interfaces. Moreover,
driven by the accompanying electron injection toward ordered chains
and hole blocking in disordered chains, semicrystalline heptazine-based
melon showed an ∼7-fold promotion in electron concentration
with respect to its pristine counterpart. Benefiting from these, the
semicrystalline sample exhibited dramatic enhancements in electron-involved
photocatalytic processes, such as superoxide radical production and
selective alcohol oxidation. This work brightens excitonic aspects
for the design of advanced photocatalysts
