Positive Electrofluorochromism of BODIPY–Ferrocene Monolayers on ITO

A borondipyrromethene (BODIPY)–ferrocene dyad where both units are connected by an ethynylstyryl linker was synthesized, and its fluorescence and electrochemical and electrofluorochromic features were analyzed first in solution and then as a surface-confined species. Immobilization was achieved by a siloxane derivatization at the meso position of the BODIPY, which enabled covalent grafting onto the ITO surface. The resulting monolayer showed high stability in the redox response and positive electrofluorochromism. Fluorescent emission was indeed switched on upon oxidation and monitored electrochemically, with good reversibility across cycles. This demonstrated that electrofluorochromic properties could be transposed from solution to the surface in the case of dyads whose emission is initially quenched.