Photoluminescence spectra of thin films of ZnTPP-C$_{60}$ and CuTPP-C$_{60}$ molecular complexes

The results of studies of thin composite films of zinc and copper tetraphenylporphyrins with different fractions of fullerene C$_{60}$ are reported. The photoluminescence spectra are recorded, and the composition and surface morphology are analyzed by means of scanning electron microscopy. The results show a difference in the structure of films with two types of metals (Zn, Cu) entering into the complex of the porphyrin macrocycle. An additional long-wavelength photoluminescence band at 1.4 eV is detected for the first time, which is evidence of the formation of ZnTPP–C$_{60}$ molecular complexes from a gas-dynamic vapor flow upon condensation. In CuTPP thin films, the processes of self-assembly into nanowires 20 nm in diameter and up to 50 $\mu$m in length and the formation of nanoheterojunctions upon the addition of fullerene C$_{60}$ are observed. Quantum-chemical calculations in the context of density-functional theory are carried out to interpret the experimental data.