11:15 〜 11:30
▼ [9a-Z26-6] Directional exciton diffusion in pentacene-decorated carbon nanotubes
キーワード：carbon nanotube, organic molecule, exciton
Photoluminescent carbon nanotubes are anticipated to become versatile room-temperature single-photon sources that are crucial for quantum information processing. The optical processes in carbon nanotubes are dominated by the so-called excitons, whose binding energies are sensitive to the surrounding dielectric environment. To modify the exciton properties in carbon nanotubes, molecular adsorption has been proven as an effective approach. When suitable molecules are adsorbed onto a nanotube, excitons nearby are expected to accumulate at the adsorbed site and engage in enhanced exciton-exciton annihilation, leading to single-photon emission at wavelengths modulated by the molecules.
Here, by decorating individually suspended single-walled carbon nanotubes with isolated pentacene particles, we demonstrate tuning of the excitonic energies and directional exciton diffusion induced by molecular screening. Pentacene particles with controllable sizes in the range of tens of nanometers are deposited onto the nanotubes via thermal evaporation. Bright photoluminescence is observed, and peaks corresponding to the pristine region and the pentacene-adsorbed site on the nanotube can be distinguished in the photoluminescence excitation spectra. The excitonic energies are lowered at the adsorbed site compared to that in the pristine region as evidenced by the redshifted emission wavelengths. Importantly, directional exciton diffusion is achieved, where excitons transfer from the pristine region to the adsorbed site on the nanotube due to the energy difference. Time-resolved photoluminescence measurements reveal the exciton lifetimes, and photon antibunching is demonstrated in the adsorbed region.
Here, by decorating individually suspended single-walled carbon nanotubes with isolated pentacene particles, we demonstrate tuning of the excitonic energies and directional exciton diffusion induced by molecular screening. Pentacene particles with controllable sizes in the range of tens of nanometers are deposited onto the nanotubes via thermal evaporation. Bright photoluminescence is observed, and peaks corresponding to the pristine region and the pentacene-adsorbed site on the nanotube can be distinguished in the photoluminescence excitation spectra. The excitonic energies are lowered at the adsorbed site compared to that in the pristine region as evidenced by the redshifted emission wavelengths. Importantly, directional exciton diffusion is achieved, where excitons transfer from the pristine region to the adsorbed site on the nanotube due to the energy difference. Time-resolved photoluminescence measurements reveal the exciton lifetimes, and photon antibunching is demonstrated in the adsorbed region.