Short-Range π–π Stacking Assembly on P25 TiO2 Nanoparticles for Enhanced Visible-Light Photocatalysis

Utilization of the renewable solar fuel based on a perylenetetracarboxylic acid diimide (PTCDI)–semiconductor composite represents an effective method to solve the energy crisis; however, most applications have focused on dye sensitization of the monomolecular layer. Here the synergy effect of PTCDI self-assembly and P25 nanoparticles (NPs) has been elucidated systematically from the PTCDI stacking structure on P25 NP and electron transfer (ET) mode, for which the visible-light photocatalytic activity of PTCDI self-assembly through the assistance of P25 has been acquired and enhanced, even up to 7 times with the addition of EDTA. It has been found that self-assembly of PTCDI nanowires (NWs) as building blocks has been reconstructed on P25 NP via arrangement of short-range π–π stacking that is important for high photocatalytic activity. We inferred that the indentation plays a key role in the formation of the short-range π–π stacking mode on the basis of the results of XRD, photoluminescence, transient decay spectroscopy, and photocurrent measurements. In addition to that, a substantial part of the electrons excited in the interfacial layer of the PTCDI shell are injected into the conduction band of P25, thus preventing charge recombination. Our findings will provide guidance for photocatalytic enhancement of the organic self-assembly.