Bulk-heterojunction polymer photovoltaic cells manufactured using non-halogenated and non-aromatic solvent

Abstract

The use of photovoltaic devices as converters of solar energy into electricity is a relevant technology to the global energy needs and, at the same time, it mitigates the negative impact on the environment caused by conventional sources. Although polymer solar cells are properly considered as clean and renewable source of electricity production, the processing involved in the manufacture of such devices still contains toxic elements. The formation of thin films of active layer in bulk-heterojunction organic solar cells, as example, usually uses halogenated solvents as chlorobenzene (CB), dichlorobenzene (DCB), or chloroform (CF), which represent certain risks of toxicity to the human body and to the environment. This work aims to show that it is possible to manufacture organic solar cells using less-toxic solvents, in special to the environment, whose final efficiency results are similar to those that have been processed by conventional halogenated solvents. With the aid of the Hansen solubility parameters (HSP), we identified non-halogenated and non-aromatic solvent that showed chemical compatibility with donor polymers and acceptor molecules used in the device's active layer. The fabricated devices were then characterized and their photovoltaic responses compared to the conventional equivalents.