Amphiphilic and chiral unsymmetrical perylene dye for solid-state dye-sensitized solar cells

A novel amphiphilic, unsymmetrically substituted N-((2S)-2-aminohexanoic acid)-N'-[(S)-1-phenylethyl]-3,4,9,10- perylenetetracarboxydiimide with 2 different chiral centers was synthesized and characterized. Chiral amphiphilicity, which can be tunable between hydrophilic and hydrophobic parts, is responsible for controlled self-assembly through intermolecular hydrogen bonding (N-H center dot center dot center dot O). The product showed high thermal stability but partial solubility in common organic solvents. We observed 2 isosbestic points at 533 and 611 nm, confirming the presence of overlapped monomer and excimer emissions in the temperature range of 10-80 degrees C. Fluorescence quenching in m-cresol was attributed to charge-transfer interactions. Importantly, the excited state of the chiral dye can decay only by fluorescence in the solid state, mainly due to O-H center dot center dot center dot N hydrogen bonds. Novel red-light-emitting (lambda(em) = 658 nm) chiral perylene dye has a great potential for solid-state lighting technologies.