Effect of Solvent Polarity and Electrophilicity on Quantum Yields and Solvatochromic Shifts of Single-Walled Carbon Nanotube Photoluminescence

In this work, we investigate the impact of the solvation environment on single-walled carbon nanotube (SWCNT) photoluminescence quantum yield and optical transition energies (E_ii) using a highly charged aryleneethynylene polymer. This novel surfactant produces dispersions in a variety of polar solvents having a wide range of dielectric constants (methanol, dimethyl sulfoxide, aqueous dimethylformamide, and deuterium oxide). Because a common surfactant can be used while maintaining a constant SWCNT–surfactant morphology, we are able to straightforwardly evaluate the impact of the solvation environment upon SWCNT optical properties. We find that (i) the SWCNT quantum yield is strongly dependent on both the polarity and electrophilicity of the solvent and (ii) solvatochromic shifts correlate with the extent of SWCNT solvation. These findings provide a deeper understanding of the environmental dependence of SWCNT excitonic properties and underscore that the solvent provides a tool with which to modulate SWCNT electronic and optical properties.