TY - JOUR T1 - Wavelength-dependent hot electron relaxation in PVP capped CdS/HgS/CdS quantum dot quantum well nanocrystals JF - Journal of Physical Chemistry B Y1 - 2004 A1 - Schill, A. W. A1 - El-Sayed, Mostafa A AB - Subpicosecond pump-probe transient absorption spectroscopy has been used to examine the probe wavelength-dependent kinetics of PVP capped CdS/HgS/CdS quantum dot quantum well nanoparticles. Using 398- and 520-nm excitations, the relaxation of the excited hot electrons above the band gap state is characterized by both rapid electronic nonradiative relaxation and slower thermal relaxation processes. The wavelength dependence of both the fast rise and fast decay of the transient bleach is discussed in terms of electronic relaxation processes involving mixed CdS/HgS states at short probe wavelengths or pure HgS states at long probe wavelengths. The slow decay of the transient bleach is discussed in terms of a thermal relaxation process leading to the dissipation of heat from the hot nanoparticle lattice to the surrounding medium. VL - 108 SN - 1520-6106 N1 - Schill, AW El-Sayed, MA M3 - 10.1021/jp047832u ER - TY - JOUR T1 - Why is the thermalization of excited electrons in semiconductor nanoparticles so rapid? Studies on CdSe nanoparticles JF - Chemical Physics Letters Y1 - 2003 A1 - Darugar, Q. A1 - Landes, Christy F. A1 - Link, Stephan A1 - Schill, A. W. A1 - El-Sayed, Mostafa A AB - Quantum confinement of electronic motion in semiconductor nanoparticles leads to quantization of its band continua of the bulk. The relaxation between the resulting quantized levels by electron phonon coupling was expected, but not found, to be slow due to the small phonon frequencies (phonon bottleneck). Studying the electronic relaxation from the band gap and a higher excited state in CdSe dots and rods under different perturbations suggest the importance of coupling the excited electron to the surface. The surface species act as an efficient heat bath or as electron trapping sites in the linear or nonlinear (Auger) relaxation processes. (C) 2003 Elsevier Science B.V. All rights reserved. VL - 373 SN - 0009-2614 N1 - Darugar, Q Landes, C Link, S Schill, A El-Sayed, MA M3 - 10.1016/s0009-2614(03)00213-6 ER -