Trap-Assisted Exciton Dissociation Through Continuous Trapping/Detrapping in Lithium Ions Inserted Crystalline Carbon Nitride

Here, lithium ions inserted crystalline carbon nitrides (LCCN) with different defect concentrations are prepared by elaborately regulating the mass transfer process in thermal polymerization. It is revealed that there is no conventional exciton–polarons-induced exciton dissociation mechanism in LCCN due to the weak coupling between excitons and phonons. On the contrary, excitons continue to trap/detrap through defect-induced traps, which weakens the Coulomb force between electron–hole pairs, thereby accelerating exciton dissociation. It is worth emphasizing that this is the first systematic research on the exciton dissociation characteristics and photocatalytic activity of LCCN of poly(heptazine imide) structure. A strategy of assisting exciton dissociation through defect-induced traps to address the inherently high exciton binding energy and low exciton dissociation efficiency issues in polymer photocatalysts is proposed.