Bifunctional capping of CdS nanoparticles and bridging to TiO2

2019-05-11 10:07:27

transfer TiO2 particles electron CdS

责任者: Lawless, D.;Kapoor, S.;Meisel, D. 单位: Argonne Natl, IL, USA 来源出处: Journal of Physical Chemistry,1995,99(25):10329-10335 摘要: We report on the preparation of quantum-sized CdS particles capped with three bifunctional mercaptocarboxylic acids (HS-(CH2)n-CO2H, n = 1-3). The absorption spectra of all three colloid preparations exhibit a new band at 365 nm, assigned to a charge transfer to particle transition, probably from the free carboxylate head group. Among these, mercaptobutyric acid was the most efficient acid at controlling the size of the CdS particles. TiO2 particles were attached to the CdS particles through the carboxylic end of the bifunctional caps. Bridging TiO2 to CdS through these acids leads to quenching of the blue and enhancement of the red edges of the emission spectra of CdS. This is attributed to selective electron transfer from shallow traps, but not from deeper traps, to the TiO2 particle. The efficiency of the quenching decreases upon increasing the alkyl chain length of the acid presumably because of the distance dependence of the electron transfer process. 关键词: Semiconductor materials;Cadmium compounds;Titanium dioxide;Nanostructured materials;Spectrum analysis;Electron transport properties;Physical chemistry;Cadmium sulfide;Bifucntional capping;Bridging;Electron transfer;Electron traps;Chain length