Optical excitation and energy transfer of Eu3+-doped CdS nanocrystals in reverse micelles

The electronic and optical properties of Eu3+-doped CdS nanocrystals in reverse micelles have been investigated by optical absorption, photoluminescence (PL) and PL excitation (PLE) spectra. The PL intensity of f-f transitions of Eu3+ exhibits an intriguing nanocrystal size dependence. On the analyses of the PLE spectra and the PL decay of Eu3+ f-f transition emission, we have found that the excitation of Eu3+ ions is induced by energy transfer from optically excited CdS nanocrystals through their surface states, and follows the f-f transition emissions.