Isobutrin from Butea Monosperma (Flame of the Forest): A Promising New Natural Sensitizer Belonging to Chalcone Class

Abstract

In this work, “isobutrin”, an ecofriendly sensitizer that is extracted from Butea monosperma (commonly known as “Flame of the Forest”) flowers, is introduced. It is a bright yellow pigment belonging to the chalcone class and is examined as a sensitizer for optoelectronic applications. It is observed that chelation of this dye with Ti ions results into a strong dye-TiO2 charge transfer (DTCT) band in the visible region. This Ti-Isobutrin chelate is stable, irreversible and its formation is studied using Benesi–Hildebrand plot. The locations of HOMO–LUMO states of the Ti-isobutrin chelate and the corresponding band alignment with TiO2 are obtained. Also, a thermal stability test revealed that isobutrin is stable above 100 °C.