Pyridine Anchored Organic Dyes With Benzothiadiazole As π-spacer:Effect Of Different Electron-donating Groups On Photovoltaic Performance

The sun radiates an enormous amount of energy enough to satisfy mankind’s overall energy demand and consumptions (about ten thousand times greater than what mankind uses per year). Solar energy is clean, abundant and renewable, hence holds a tremendous potential to benefit our world by diversifying our energy supply, reducing our dependence on fossil fuels, improving the quality of the air we breathe and stimulating our economy. Among several new energy technologies, solar cells utilizing the sun as energy source are the most promising with dye-sensitized solar cells (DSSCs) based on organic dye sensitizers adsorbed on nanocrystalline TiO2electrodes attracting considerable attentions because of their high incident solar light-to-electricity conversion efficiency, colorful and decorative natures and low cost of production.Two novel organic dye sensitizers based on D-π-A configuration containing identical π-spacers (benzothiadiazole, BTD) and electron acceptors (pyridine ring) but different aromatic amine electron-donating groups (triphenylamine, TPA and indoline) are designed and synthesized for practical application in dye-sensitized solar cells (DSSCs) to study the effect of the electron donating groups on the device performance. The overall conversion efficiencies (η) of DSSCs based on these dyes are in the range of3.5to3.7%, and highly dependent upon their donor moiety. Among almost all pyridine-based dyes investigated so far, these FM-type dyes have shown a highly significant improvement in overall photovoltaic device performance with FM-2dye utilizing a methyl-substituted indoline moiety as an electron donor; short-circuit photocurrent densities (Jsc)7.48mA cm-2, Open-circuit photovoltage (Voc)0.681mV, fill factor (FF)72%, solar energy-to-electricity conversion (n)3.7%, proving to be the most promising and of potential interest for future scientific research.