Study of mesoporous CdS-quantum-dot-sensitized TiO2 films by using X-ray photoelectron spectroscopy and AFM
نویسندگان
چکیده
CdS quantum dots were grown on mesoporous TiO2 films by successive ionic layer adsorption and reaction processes in order to obtain CdS particles of various sizes. AFM analysis shows that the growth of the CdS particles is a two-step process. The first step is the formation of new crystallites at each deposition cycle. In the next step the pre-deposited crystallites grow to form larger aggregates. Special attention is paid to the estimation of the CdS particle size by X-ray photoelectron spectroscopy (XPS). Among the classical methods of characterization the XPS model is described in detail. In order to make an attempt to validate the XPS model, the results are compared to those obtained from AFM analysis and to the evolution of the band gap energy of the CdS nanoparticles as obtained by UV-vis spectroscopy. The results showed that XPS technique is a powerful tool in the estimation of the CdS particle size. In conjunction with these results, a very good correlation has been found between the number of deposition cycles and the particle size.
منابع مشابه
Preparation of CdIn2S4-CdS nanocomposite via a green route and using them in dot-sensitized solar cells for boosting efficiency
In this work In2S3 and CdS nanoparticles were prepared by a simple hydrothermal method and then annealed at 500 °C for 2 h in an Ar gas until CdIn2S4(CdIS)-CdS nanocomposites were formed. Afterwards, efficiency of the as-synthesized CdIS-CdS nanocomposite in quantum dot-sensitized solar cells (QDSSCs) was evaluated. For this purpose, the as-prepared CdIS-CdS nanocomposites were deposited on TiO...
متن کاملSynthesis of Ag-TiO2 composite nano thin film for antimicrobial application.
TiO2 photocatalysts have been found to kill cancer cells, bacteria and viruses under mild UV illumination, which offers numerous potential applications. On the other hand, Ag has long been proved as a good antibacterial material as well. The advantage of Ag-TiO2 nanocomposite is to expand the nanomaterial's antibacterial function to a broader range of working conditions. In this study neat TiO2...
متن کاملAg2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method
Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor-Ag2S (0.9 eV) quantum dots (QDs)-in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by...
متن کاملSynthesis and photoelectrochemical response of CdS quantum dot-sensitized TiO2 nanorod array photoelectrodes
A continuous and compact CdS quantum dot-sensitive layer was synthesized on TiO2 nanorods by successive ionic layer adsorption and reaction (SILAR) and subsequent thermal annealing. The thickness of the CdS quantum dot layer was tuned by SILAR cycles, which was found to be closely related to light absorption and carrier transformation. The CdS quantum dot-sensitized TiO2 nanorod array photoelec...
متن کاملSynergistic effect of ZnS outer layers and electrolyte methanol content on efficiency in TiO2/CdS/CdSe sensitized solar cells.
The effect of methanol content in water based polysulfide electrolytes in TiO(2)/CdS/CdSe quantum dot sensitized solar cells (QDSSCs) prepared by the SILAR method was studied. In addition, the effect of coating the mesoporous QD sensitized films with ZnS outer layers was investigated. Charge recombination reactions were measured using time resolved spectroscopic measurements. These studies reve...
متن کامل