We report the electrochemiluminescence (ECL) intensity of tris(2,2′-bipyridyl)ruthenium(II) [Ru(bpy)32+] as a function of varying solution viscosity in mixtures of N,N-dimethylformamide and glycerin. Diffusion coefficient (D), electron-transfer rate (k) of Ru(bpy)32+/3+, and luminescence intensity are measured and correlated with viscosity and ECL intensity (Iecl). Iecl decreases with increasing solution viscosity and tracks diffusion and electron transfer until it reaches an upper limit. This limit is reached at D = 5 × 10-7 cm2/s and k = 0.03 cm/s in this system. Normalizing Iecl for diffusion reveals a weak enhancement of ECL with increasing viscosity.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry