We independently determine the subpicosecond cooling rates for holes and electrons in CdSe quantum dots. Time-resolved luminescence and terahertz spectroscopy reveal that the rate of hole cooling, following photoexcitation of the quantum dots, depends critically on the electron excess energy. This constitutes the first direct, quantitative measurement of electron-to-hole energy transfer, the hy...

We have investigated the diameter dependence of the exciton luminescence linewidth in individual single-walled carbon nanotubes (SWNTs) by means of microphotoluminescence (μ-PL) spectroscopy. The lineshapes of μ-PL spectra for single SWNTs suspended on a patterned Si substrate at room temperature can be fitted by single Lorentzian functions. It is found that the μ-PL linewidth depends strongly ...