Application of Electrospun Nanofibers in Organic Photovoltaics

Abstract

This chapter highlights the introduction of organic thin-film solar cells and organic–inorganic hybrid solar cells and the development of electrospun nanofibers for those applications. Organic solar cells need large interfacial surface area for efficient charge separation of excitons, which are normally achieved by thermal annealing. However, this annealing is relatively not compatible with the polymers with low glass transition temperature, not compatible with flexible substrates, and also not compatible with large area devices. An alternative process that yields efficient interface of electron donor and acceptor with continuous phase of each material is necessary. Electrospinning is a good method to fabricate nanofibers of conducting polymers which can be used as electron donor materials of organic solar cells. To improve the efficiencies of organic solar cells, the combination of organic and inorganic semiconductor as organic–inorganic hybrid photovoltaic cells has been extensively investigated to overcome the low mobility of carriers by using nanostructured inorganic materials as electron acceptors and/or electron transporting layers. The use of inorganic semiconductors in the form of electrospun nanofibers as electron transporting layers is a promising alternative way. Nanofiber-based transparent electrodes can also be fabricated by electrospinning with flexible property. These electrodes are very promising to be utilized as flexible substrates for both organic thin-film solar cells and organic–inorganic hybrid solar cells.