Extended Data Fig. 1: Anisotropic facet engineering of Cu2O particles.
From: Spatiotemporal imaging of charge transfer in photocatalyst particles
a–e, SEM images obtained at low (a) and high (b) magnifications, AFM images (c), KPFM images (d), and SPVM images (e) of Cu2O particles with morphologies varying from a cube to an octahedron. Scale bars, (a) 20 μm and (b–e) 2 μm. Proportions (P) are defined as P = S{111} / (S{001} + S{111}), where S{111} and S{001} represent areas of the {111} and {001} facets, respectively. The KPFM images show that the surface potential signals increase with P, indicating a gradually decreasing p-type doping level from facet {001} to {111}. The higher surface potential of the {001} facet than that of the {111} facet on a truncated octahedral particle suggests a higher p-type doping level near the {001} facet because the two facets have the same Fermi energy. The SPVM images exhibit negative signals due to the electron transfer to the surface and indicate a larger number of electrons are distributed on the {001} facet. f, Surface potential distributions across the {001} and {111} facets indicated as lines in d. g, Histograms of the SPV signals extracted from the {001} and {111} facets of polyhedral Cu2O particles with various morphologies. Gaussian fits are used to determine the average signals. h, Correlation between the CPD and SPV signals based on the differences between the {001} and {111} facets of polyhedral Cu2O particles with various morphologies. The data are extracted from f, g.
