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DOE OSTI · 1777458

Temperature and solvent-dependent photoluminescence quenching in [Ru(bpy) 2 (bpy-cc-AQ)] 2+

Larsen, Christopher B.
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Abstract

I have herein investigated the solvent-dependent photoluminescence quenching mechanism of [Ru(bpy) 2 (bpy-cc-AQ)] 2+ using variable temperature emission spectroscopies. In this wok, the photophysics of this complex are dominated by an excited-state thermal equilibrium between a photoluminescent 3 MLCT state and a charge-separated state that lies higher in energy relative to the 3 MLCT state in low polarity solvents and approximately isoenergetic in high polarity solvents. Furthermore, an unusual photoluminescence temperature-dependence in high polarity solvents is shown to arise from competition between enthalpic factors favouring the charge-separated state and entropic factors favouring the photoluminescent 3 MLCT state, analogous to the molecular light-switch effect of [Ru(bpy) 2 (dppz)] 2+ . The solvent-dependent photoluminescence quenching of [Ru(bpy)2(bpy-cc-AQ)] 2+ is attributed to two key solvent-dependent factors: (1) the excited-state equilibrium position and (2) the rate of charge-recombination from the charge-separated state.

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Larsen, Christopher B.. 2021-01-25. Temperature and solvent-dependent photoluminescence quenching in [Ru(bpy) 2 (bpy-cc-AQ)] 2+. https://doi.org/10.1039/d0cp05044j

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