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

Abstract

We demonstrate the decoration of methylamine lead bromide (MAPbBr₃, 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 MAPbBr₃/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 MAPbBr₃/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 MAPbBr₃ 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 MAPbBr₃/g-C₃N₄ NCs. An increase in the charge transfer rate constant (k_et) for MAPbBr₃/g-C₃N₄ NCs was discovered when the constituent ratio of p-g-C₃N₄ was enhanced. Furthermore, we utilized MAPbBr₃/p-g-C₃N₄ NCs as a photocatalyst to carry out the photocatalytic reduction of p-nitrophenol (PNP) under visible-light irradiation. A significant photoreduction rate (k_PNP) of PNP was observed in the photocatalytic reaction, which indicated the great potential of MAPbBr₃/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.