Electrochemiluminescence and Charge Transport Properties of Metallopolymer-Gold Nanocomposites

Metallopolymer-gold nanocomposites were prepared by mixing 4-(dimethylamino) pyridine protected gold nanoparticles (diameter approximately 5{plus minus}0.5 nm) and [Ru(bpy)2PVP10](ClO4)2, at different mole ratios where bpy is 2,2'-bipyridyl and PVP is poly(4-vinylpyridine). The photoluminescence emission intensity of the metallopolymer is quenched approximately 72% at AuNP:Ru molar ratio of 12.5x10-2. The electrochemical and the electrochemiluminescence (ECL) properties of thin layers of the nanocomposites are reported. Significantly, despite the ability of the metal nanoparticles to quench the ruthenium based emission in solution, the electrochemiluminescence of the optimized nanocomposite films (mole ratio 6.24x10-2) is approximately 3.5 times greater than that of the parent metallopolymer. This enhancement arises from the increased rate of charge transport through the thin films that leads to a greater number of excited states per unit time while minimizing the quenching effects.