FAPbBr3 perovskite nanocrystals decorated on a graphitic carbon nitride (g-C3N4) sheet for interfacial hole transfer

Abstract

Hydrophobically capped formamidinium lead bromide (FAPbBr₃) perovskite nanocrystals (PNCs) exhibit bright green emission in the solution state. Photoluminescence (PL) spectral studies and time-correlated single photon counting (TCSPC) measurements were performed to evaluate the interfacial hole transfer phenomenon. Both the absolute photoluminescence quantum yield (PLQY) and the decay lifetime value decrease with graphitic carbon nitride (g-C₃N₄), which is attributed to the migration of holes from the ground state of the PNCs to g-C₃N₄. The quenching of emission is accompanied by a change in the lifetime value indicating the static nature of quenching. Moreover, the PL quenching phenomenon was also analyzed via electrochemical studies. The decoration of FAPbBr₃ perovskite NCs on a g-C₃N₄ sheet was analyzed via TEM images obtained. The change in the oxidation state of nanocomposites such as FAPbBr₃@g-C₃N₄ compared with pristine-FAPbBr₃ provided evidence of the modified chemical environment of FAPbBr₃.