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Synthesis and Photochemistry of Quantum‐Size Semiconductor Particles in Solution and in Modified Layers
Author(s) -
Weller H.,
Eychmüller A.,
Vogel R.,
Katsikas L.,
Hässelbarth A.,
Giersig M.
Publication year - 1993
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.199300016
Subject(s) - chemistry , exciton , photocurrent , dispersity , crystallite , semiconductor , electron , quantization (signal processing) , electron transfer , band gap , chemical physics , fluorescence , particle size , quantum , quantum dot , electrode , photoinduced electron transfer , photochemistry , molecular physics , optoelectronics , condensed matter physics , optics , quantum mechanics , physics , crystallography , organic chemistry , computer science , computer vision
We describe the preparation of highly monodisperse, quantum‐size CdS particles. In these samples a band splitting into discrete exciton‐like states is observed. A mechanism for the excitonic fluorescence is presented involving shallow traps as a reservoir for electrons which finally recombine with free positive holes across the bandgap. Quantum‐size CdS and PbS particles prepared in situ on highly porous, polycrystalline TiO 2 electrodes work as highly efficient sensitizers. Photocurrent yields of more than 70% are reported. In the case of PbS, it is shown that an efficient electron transfer is possible only with particles in the size of the quantization regime.