Novel TPD-based organic D-π-A dyes for dye-sensitized solar cells

摘要

A novel class of organic D-π-A dyes employing a N,N.N',N'-tetraphenylbenzidine (TPD) unit as donor was designed and synthesized for dye-sensitized solar cells, which achieved a solar-to-electricity conversion efficiency (η) of 5.63% in preliminary tests as compared to 6.42% for N3 dye under the same experimental conditions.rnEnergy demands and environmental pollution resulting in global warming have led to an intense focus all over the world on renewable energy sources over the past decades. Since the first report in 1991 by Gratzel and coworkers, dye-sensitized nanocrystalline solar cells (DSSCs) based on organic optoelectronic materials have received ever-increasing attention as potential alternatives to traditional inorganic photovoltaic devices. These cells are usually composed of a wide band gap TiO_2 semiconductor deposited on a transparent conducting substrate, an anchored molecular sensitizer and a redox electrolyte. DSSCs based on Ru-complex photo-sensitizers such as N3 and black dye can provide efficient solar energy-to-electricity conversion efficiency (η) up to 11 % at simulated AM 1.5 G irradiation. In recent years, interest in organic dyes as an alternative to noble metal complexes has increased due to many advantages, such as diversity of molecular structures, high molar extinction coefficient, simple synthesis as well as low cost and environmental issues. Metal free organic dyes such as squaraine, merocyanine, indoline, fluorene, coumarin and triphenylamine organic dyes have been developed and show promising performances.