Effect of water vapor on the operation and stability of tris(2,2′-bipyridine)ruthenium(II)-based light-emitting electrochemical cells

Light-emitting electrochemical cells (LECs) based on Ru(bPY)(3)(ClO4)(2) are thin-film solid-state devices that typically operate at low applied voltages and show relatively high efficiencies. They suffer, however, from poor operating lifetimes. A proposed source of lifetime degradation is water in the film. Previous studies have revealed a marked difference in operation performance between cells fabricated and tested inside a drybox and those made and tested under ambient conditions. This study further characterized the effect of water vapor on device operation. The role of water as solvent within the thin-film devices was found to increase the current and the initial light output, but at the expense of more rapid decay in light generation.