| 초록 |
We report the temperature dependence of the optical absorption and emission spectra of quantum dots (QDs) for three different nanocrystal structures (CdSe core, CdSe/CdS core/shell, and CdSe/CdS/ZnS core/multishell) in solid film state. For this, the transparent single-walled carbon nanotube film attached on the QD thin layer has been newly tried to use as a heater. The temperature dependence of spectral shifts in both absorption and emission of QDs was measured in the range of 300 ~ 450 K, and the Stokes shift was calculated by taking the energy difference between the absorption and emission peaks. As the result, we found that Stoke shift decreased as the QD shell added as well as the temperature increased, denoting a weaker electron-phonon coupling in QD with additional shell and at higher temperature. Finally, the band gap of QDs was measured as a function of temperature and its Debye temperature was obtained by fitting the energy band gap using empirical expression. |
