A new hydrogel from an amino acid-based perylene bisimide and its semiconducting, photo-switching behaviour

Abstract

A new, stable, semiconducting, photo-responsive, amino acid (L-tyrosine) based perylene bisimide derivative (PBI-Y) was found to form pH-sensitive hydrogels. This gelator molecule (PBI-Y) has undergone hydrogelation at 50 mM phosphate buffer at pH 5.00–9.00. Different minimum gelation concentration values (MGC) were recorded in different pHs at the same phosphate buffer strength (50 mM). The hydrogel was also characterized using different techniques, including X-ray diffraction analysis, rheology and FT-IR study. The fluorescence and cyclic voltammetric responses of the PBI-Y hydrogelator can be tuned by changing the pH. The PBI-Y hydrogelator has shown self-assembled nanofibrillar network structures, as it has been evident from the field emission scanning electron microscopic (FE-SEM), as well as transmission electron microscopic analyses (TEM). This PBI-Y hydrogel has also shown interesting semiconducting behaviour. This PBI-Y hydrogelator-based photoconductor was found to exhibit excellent photo-switching behaviour with a high photo-response value. This holds a future promise for the creation of PBI-conjugated functional soft-materials-based photodetectors and photovoltaics.