Application of Novel Calix[4]arene Metal-free Sensitizers in Dye-sensitized Photoelectrochemical Cells for Water Splitting

Abstract

A series of novel calix[4]arene metal-free dyes, featuring macrocyclic structure and unique conical confor-mation, has been introduced into photoanode-based dye-sensitized electrochemical cell system as photosensitizers. The electrochemical properties of the corresponding sensitized photoanodes were systematically studied in the absence/ presence of water oxidation catalyst(WOC). Furthermore, the visible-light-driven overall water-splitting reactions were conducted by fully assembled devices, obtaining a performance trend of Calix-3 Calix-2 Calix-1. The corresponding device of Calix-3 exhibited the best photoactivity, giving an initial photocurrent density of ca. 300 μA/cm2, an IPEC peak value of ca. 9.0% at 365 nm and a wide photo-respond band up to ca. 620 nm. The best performance of Calix-3 can be attributed to its most effective light-harvesting ability, best ICT transition property, highest oxidation potential and thus best ability of activating WOC. This work offers an inspiration for the application of new-type effective metal-free sensitizers in photocatalytic water-splitting device.