Fig. 4

Hot electron relaxation in Cu-doped QDs. a TA spectra of Cu:CdSe QDs probed at indicated time delays following the excitation by a 640-nm pulse. b TA kinetics probed at the X (light red circles) and CT (dark red squares) band bleaches following the excitation by a 640-nm pulse. c TA spectra of Cu:CdSe QDs probed at indicated time delays following the excitation by a 400-nm pulse. d TA kinetics probed at the X (light red circles), CT (dark red squares), and 1P (blue triangles) band bleaches following the excitation by a 400-nm pulse. Note that the CT and 1P band signals have been amplified by factors of 3 and 4, respectively. Also shown is the u-PL kinetics of CT band emission (scaled and inverted; gray open squares) measured under 400 nm excitation with <N>~ 4. e, f Similar plots as (c, d) for undoped CdSe QDs