Enhanced internal electric field suppressing non-radiative recombination in boron doped poly(heptazine imide)

Non-radiative recombination is the key bottleneck to overcome the charge separation problem. Here, we use poly(heptazine imide) (PHI) as a model photocatalyst to investigate the effect of internal electric field (IEF) on non-radiative recombination. Introducing electron-deficient boron atoms into the PHI structure leads to an uneven distribution of in-plane charges, spontaneously polarizing the formation of an IEF. This enhanced IEF can exert a force on the carrier in the opposite direction of the Coulomb force, thus effectively weakening the carrier trapping by the charged defect, thereby suppressing the non-radiative recombination. This is the first systematic research of suppressing non-radiative recombination by IEF in photocatalysis, which provides guiding strategies for addressing the bottleneck of charge separation in photocatalysis.