Phosphorescence quenching of -tris(2-phenylpyridyl)iridium() complexes in thin films on dielectric surfaces

• Published in: Physical chemistry chemical physics : PCCP 2016-01, Vol.18 (5), p.3575-358
• Main Authors: Ribierre, J. C, Ruseckas, A, Staton, S. V, Knights, K, Cumpstey, N, Burn, P. L, Samuel, I. D. W
• Format: Article
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c5cp06584d

We study the influence of the film thickness on the time-resolved phosphorescence and the luminescence quantum yield of fac -tris(2-phenylpyridyl)iridium( iii ) [Ir(ppy) 3 ]-cored dendrimers deposited on dielectric substrates. A correlation is observed between the surface quenching velocity and the quenching rate by intermolecular interactions in the bulk film, which suggests that both processes are controlled by dipole-dipole interactions between Ir(ppy) 3 complexes at the core of the dendrimers. It is also found that the surface quenching velocity decreases as the refractive index of the substrate is increased. This can be explained by partial screening of dipole-dipole interactions by the dielectric environment. Surface quenching of triplet excitons at the film interface is investigated in iridium-cored phosphorescent dendrimer films.