Enhanced Photocatalytic Oxygen Evolution Using Copper‐Coordinated Perylene Diimide Nanorod Assemblies

A crystalline supramolecular photocatalyst is prepared through metal‐induced self‐assembly of perylene diimide with imidazole groups at the imide position (PDI‐Hm). Exploiting the metal‐coordination ability of imidazole, a crystalline assembly of copper‐coordinated PDI‐Hm (CuPDI‐Hm) in a nanorod shape is prepared which displays an outstanding photocatalytic oxygen evolution rate of 25,900 μmol g‐1 h‐1 without additional co‐catalysts. The imidazole‐copper coordination, along with π‐π stacking of PDI frameworks, guides the arrangement of PDI‐Hm molecules to form highly crystalline assemblies. The coordination of copper also modulates the size of the CuPDI‐Hm supramolecular assembly by regulating the nucleation and growth processes. Furthermore, the imidazole‐copper coordination constructs the electric field within the PDI‐Hm assembly, retarding the recombination of photo‐induced charges to enhance the photoelectric/photocatalytic activity when compared to Cu‐free PDI‐Hm assemblies. Small CuPDI‐Hm assembly exhibits higher photocatalytic activity due to their larger surface area and reduced light scattering. Together, the Cu‐imidazole coordination presents a facile way for fabricating size‐controlled crystalline PDI assemblies with built‐in electric field enhancing photoelectric and photocatalytic activities substantially.