Preparation of CdSe/CdS NRs. Colloidal CdSe/CdS NRs were synthesized using a seeded growth method previously described by Carbone et. al. The as-synthesized nanorods were precipitated with the addition of methanol as an anti-solvent and purified by centrifugation at 3000 RCF for 8 minutes. The resulting precipitate was further cleaned by resuspending in a mixture of hexane and methanol followed by centrifugation at 3000 RCF for 8 minutes. This purification step was repeated twice before the final precipitate was resuspended in 10 mL of anhydrous hexane and stored under argon for further analysis.