Methylamine lead bromide perovskite/protonated graphitic carbon nitride nanocomposites: interfacial charge carrier dynamics and photocatalysis

We demonstrate the decoration of methylamine lead bromide (MAPbBr(3), MA: CH3NH3+) perovskite nanoparticles on protonated graphitic carbon nitride (p-g-C3N4) sheets to form nanocomposites (NCs) for the first time. The intrinsic type II band structure of MAPbBr(3)/p-g-C3N4 NCs resulted in significant charge separation properties, which were greatly beneficial for related applications in photoelectric conversion. The interfacial charge transfer behavior of MAPbBr(3)/p-g-C3N4 NCs was analyzed via time-resolved photoluminescence (TRPL) spectroscopy and singular-value decomposition global fitting (SVD-GF), which revealed that photoexcited electrons in the conduction band (CB) and shallow-trap (ST) states of MAPbBr(3) could be transferred into the CB of g-C3N4. The fitting results for TRPL traces indicated that the control of the related compositions could modulate the interfacial charge carrier dynamics of MAPbBr(3)/g-C3N4 NCs. An increase in the charge transfer rate constant (ket) for MAPbBr(3)/g-C3N4 NCs was discovered when the constituent ratio of p-g-C3N4 was enhanced. Furthermore, we utilized MAPbBr(3)/p-g-C3N4 NCs as a photocatalyst to carry out the photocatalytic reduction of pnitrophenol (PNP) under visible-light irradiation. A significant photoreduction rate (kPNP) of PNP was observed in the photocatalytic reaction, which indicated the great potential of MAPbBr(3)/p-g-C3N4 NCs to convert solar energy into chemical energy. In particular, the present investigation opens a new field for organolead bromide perovskites in applications in photocatalysis, as well as related photoelectric conversion.