Quantum efficiency of energy transfer in noncovalent carbon nanotube/porphyrin compounds

Abstract

We report on the quantum yield of excitation energy transfer in noncovalently bound nanotube/porphyrin compounds. Evidence for energy transfer is gained from photoluminescence excitation experiments. We perform a quantitative evaluation of the transfer quantum yield in the case of (6,5) nanotubes through three independent methods: quantitative photoluminescence excitation measurements, evaluation of the luminescence quenching of the donor (porphyrin) and ultrafast transient absorption measurements. The latter shows a tremendous increase in the porphyrin recovery rate upon incorporation in the compound. All these measurements consistently lead to an exceptional quantum yield: η∼1(10−5<1−η<10−3).