Photoinduced formation of singlet oxygen with PCBM–Pd polymer in solution and at the surface

Abstract

The polymeric material of PCBM–Pd was prepared using both electrochemical and chemical synthesis. The electrochemical synthesis was carried out in acetonitrile/toluene (1 : 4, v/v) solution containing PCBM, palladium acetate, and tetra(n-C₄H₉)₄NClO₄ as the supporting electrolyte. The polymeric film was grown at the Au electrode surface under cyclic voltammetry conditions. Chemical synthesis was performed in a benzene solution containing PCBM and Pd₂(dba)₃·CHCl₃. This study investigates singlet oxygen's morphology, structural properties, and photochemical generation in this synthesized n-polymer. The morphology of the PCBM–Pd polymer was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and nitrogen adsorption/desorption isotherms (BETs) were used for the structural characterization of this polymeric material. The formation of ¹O₂ by the photoactive PCBM–Pd polymer was confirmed using 2,3,4,5-tetraphenylcyclopentadienone (TPCPD) as a specific singlet oxygen quencher. Under these conditions, the photogeneration of singlet oxygen differs depending on the molar ratio of PCBM to Pd. The photochemical generation of singlet oxygen for the PCBM–Pd polymer electrochemically deposited on an ITO electrode and gold foil does not depend on the thickness of the deposited layer.