Electrochemical Synthesis of Composites Based on Polythiophenes and Carbon Materials for Use in Photovoltaic Systems

Solar radiation is the renewable energy source with practically unlimited access. Scientific research has development devices capable of transforming this vast resource into electrical energy (solar cells). The organic solar cells (OSC) have emerged as a promising photovoltaic (PV) technology because of he possibility of low cost production and flexible devices. In a normal structured OSC device, the active layer of donor–acceptor blend is sandwiched between the indium tin oxide or ITO (anode) coated on the glass substrate and a low work function metal (cathode).  The active layer of OPV is constituted by a mixture of a polymer electron-donating (conjugated polymer) and electron-acceptor compounds (usually fullerene derivatives). This material is blended in a bulk heterojunction architecture in order to enhance the performance device. Currently there are several ways to deposit the active layer (spary coting, thermal evaporation, spin coating), using mainly polymeric chains, aqueous systems and high weight molecules.

The use of electrochemical techniques for the development of conductive polymers, has primarily focused on understanding the mechanisms of polymerization, growth and redox behavior of these. The use of these methods has resulted in the development of polymer films with potential use in transistors, diodes and others.

The aim of this research is the development of photovoltaic devices using electrochemical techniques (cyclic voltammetry and constant potential) to generate the active layer of a conventional device. Performing in situ polymerization, incorporating of  electroaceptor material in organic solvents.

The deposits of the active layer is made using a three electrode cell convecional, ITO working electrode, a platinum plate counter electrode, and Ag/AgNO3 reference electrode in acetonitrile, using bithiophene as electron donor molecules, oxidized multi-walled carbon nanotubes, oxidized graphene, ICBA and PCBM as acceptor molecules. Getting different morphologies and behaviors. Morphological analysis of the films were performed using an atomic force microscope (AFM). Determining the morphology and thickness of these layers.

The photovoltaic device was completed using Wood's metal as cathode, thus different devices were obtained.

Finally, the JV curves were obtained of the photovoltaic devices.