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Journal of Physical Chemistry C. 01/2012; 116(47):25119-25125.
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ABSTRACT: Efficient solar energy conversion is strongly related to the development of new materials with enhanced functional properties. In this context, a wide variety of inorganic, organic or hybrid nanostructured materials have been investigated. In particular, in hybrid organic-inorganic nanocomposites are combined the convenient properties of organic polymers, such as easy manipulation and mechanical flexibility, and the unique size dependent properties of nanocrystals (NCs). However, applications of hybrid nanocomposites in photovoltaic devices require a homogeneous and highly dense dispersion of NCs in polymer in order to guarantee not only an efficient charge separation but also an efficient transport of the carriers to the electrodes without recombination. In previous works we demonstrated that cadmium thiolate complexes are suitable precursors for the in-situ synthesis of nanocrystalline CdS. Here, we show that the soluble [Cd(SBz)2]2.(1-methylimidazole) complex can be efficiently annealed in a conjugated polymer obtaining a nanocomposite with a regular and compact network of NCs. The proposed synthetic strategies require annealing temperatures well below 200°C and short time for the thermal treatment, i.e. less than 30 min. We also show that the same complex can be used to synthesize CdS NCs in mesoporous TiO2. The adsorption of cadmium thiolate molecule in TiO2 matrix can be obtained by using chemical bath deposition technique and subsequent thermal annealing. The use of NCs, quantum dots, as sensitizers of TiO2 matrices represents a very promising alternative to common dye-sensitized solar cells and an interesting solution for heterogeneous photocatalysis.
Journal of Nanoparticle Research 03/2011; · 3.29 Impact Factor
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Polymer Composites 01/2010; 31:1075. · 1.23 Impact Factor
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ABSTRACT: Polymer films embedding cadmium thiolate precursors have been irradiated with ultraviolet laser pulses resulting in the formation of cadmium sulfide crystalline nanoparticles through a macroscopically non-destructive procedure for the host matrix. Controlling the number of the incident laser pulses, the gradual increase of the size of the nanoparticles is accomplished, and consequently the progressive change of the emission characteristics of the formed nanocomposites. The X-ray diffraction and transmission electron microscopy measurements were used for the full characterization of the nanoparticles. This study compares two polymer matrices, poly(methyl methacrylate) and a cyclic olefin copolymer, and reveals the importance of each one for the emission characteristics of the formed cadmium sulfide nanocrystals. It is found that the poly(methyl methacrylate) matrix contributes to the increase of the trap states on the surface of the formed nanocrystals, causing the broadening of their emission. On the other hand the cadmium sulfide nanoparticles, grown into the cyclic olefin copolymer matrix, exhibit narrower emission spectra.
Journal of Nanoscience and Nanotechnology 01/2010; 10(2):1267-1272. · 1.56 Impact Factor
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ABSTRACT: A method of in situ formation of patterns of size controlled CdS nanocrystals in a polymer matrix by pulsed UV irradiation is presented. The films consist of Cd thiolate precursors with different carbon chain lengths embedded in TOPAS polymer matrices. Under UV irradiation the precursors are photolyzed, driving to the formation of CdS nanocrystals in the quantum size regime, with size and concentration defined by the number of incident UV pulses, while the host polymer remains macroscopically/microscopically unaffected. The emission of the formed nanocomposite materials strongly depends on the dimensions of the CdS nanocrystals, thus, their growth at the different phases of the irradiation is monitored using spatially resolved photoluminescence by means of a confocal microscope. X-ray diffraction measurements verified the existence of the CdS nanocrystals, and defined their crystal structure for all the studied cases. The results are reinforced by transmission electron microscopy. It is proved that the selection of the precursor determines the efficiency of the procedure, and the quality of the formed nanocrystals. Moreover it is demonstrated that there is the possibility of laser induced formation of well-defined patterns of CdS nanocrystals, opening up new perspectives in the development of nanodevices.
Nanotechnology 05/2009; 20(15):155302. · 3.98 Impact Factor
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Microelectronic Engineering 01/2009; 86:816. · 1.56 Impact Factor
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Nanotechnology. 01/2009; 20:155302.
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ABSTRACT: The nucleation and growth of CdS nanoparticles within a polymer matrix was followed by in-situ synchrotron X-ray diffraction. The nanoparticles form by effect of the thermolysis of thiolate precursors at temperatures between 200 and 300 Celsius degrees. Above 240 Celsius degrees the precursor decomposition is complete and CdS nanoparticles grow in the polymer matrix forming a nanocomposite with interesting optical properties. The nanoparticle structural properties (size and crystal structure) depend on the annealing temperature.(abridged version)
08/2006;
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ABSTRACT: We deposited thin layers of CdS and ZnS nanoparticles embedded in a thermoplastic cyclo-olephin copolymer (COC) with elevated optical transparency and highly bio-compatible. The nanoparticles were obtained by thiolate precursors previously dispersed in the polymer upon thermal treatment at temperatures ranging between 200 and 300 Celsius degrees depending on the desired size. The precursor/polymer solutions were spin coated in order to get thin films. The samples were mainly characterised by X-ray reflectivity (XRR) and by High Resolution Transmission Electron Microscopy (HRTEM) analyses. The HRTEM measurements showed that the nanoparticles have quasi-spherical shape without evident microstructural defects. The size of the nanoparticles depends on the annealing temperature, e.g. at 232 Celsius degrees the size of the CdS nanoparticles is about 4-5 nm.
08/2006;
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Phys. Status Solidi B 244(2007)8,2768-2781.
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ABSTRACT: Cited By (since 1996): 4, Export Date: 17 April 2012, Source: Scopus, doi: 10.1021/jp104097w, Language of Original Document: English, Correspondence Address: Resta, V.; ENEA, Unità Tecnica Tecnologie Dei Materiali Brindisi (UTTMATB), Strada Statale 7 Appia-706, I-72100 Brindisi, Italy; email: vincenzo.resta@enea.it, References: Burda, C., Chen, X., Narayanan, R., El-Sayed, M.A., (2005) Chem. Rev., 105, p. 1025;
Journal of Physical Chemistry C. 114(41):17311-17317.
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ABSTRACT: Conference code: 87784, Export Date: 17 April 2012, Source: Scopus, CODEN: MRSPD, doi: 10.1557/opl.2011.1231, Language of Original Document: English, Correspondence Address: Laera, A.M.; ENEA, Unità Tecnica Tecnologia dei Materiali Brindisi (UTTMATB), S.S. 7 Appia km 706, 72100 Brindisi, Italy, References: Sanchez, C., Judeinstein, P., (1996) J. Mater. Chem., 6, p. 511;
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ABSTRACT: Cited By (since 1996): 2, Export Date: 17 April 2012, Source: Scopus, CODEN: PSSAB, doi: 10.1002/pssa.200983743, Language of Original Document: English, Correspondence Address: Resta, V.; ENEA, Unitá Tecnica Tecnologie dei Materiali Brindisi (UTTMATB), Centro Ricerche Brindisi, Strada Statale 7 Appia, 72100 Brindisi, Italy; email: vincenzo.resta@enea.it, References: Shen, Y.-J., Lee, Y.-L., (2008) Nanotechnology, 19, p. 045602;
Physica Status Solidi (A) Applications and Materials Science. 207(7):1631-1635.
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ABSTRACT: Cited By (since 1996): 5, Export Date: 17 April 2012, Source: Scopus, CODEN: MIENE, doi: 10.1016/j.mee.2008.12.050, Language of Original Document: English, Correspondence Address: Fragouli, D.; NNL-National Nanotechnology Laboratory, INFM, CNR, Via Arnesano, 73100 Lecce, Italy; email: despina.fragouli@unile.it, References: Warner, J.H., Watt, A.A.R., Tilley, R.D., (2005) Nanotechnology, 16, pp. 2381-2384;
Microelectronic Engineering. 86(4-6):816-819.
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ABSTRACT: Export Date: 17 April 2012, Source: Scopus, doi: 10.1007/s11051-011-0304-4, Language of Original Document: English, Correspondence Address: Resta, V.; ENEA, UTTMATB, Centro Ricerche Brindisi, Strada Statale Appia km. 706, 72100 Brindisi, Italy; email: vincenzo.resta@enea.it, Chemicals/CAS: cadmium sulfide, 1306-23-6; carbimazole, 22232-54-8; titanium dioxide, 1317-70-0, 1317-80-2, 13463-67-7, 51745-87-0, References: Antolini, F., Pentimalli, M., Di Luccio, T., Terzi, R., Schioppa, M., Re, M., Mirenghi, L., Tapfer, L., Structural characterization of CdS nanoparticles grown in polystyrene matrix by thermolytic synthesis (2005) Materials Letters, 59 (24-25), pp. 3181-3187. , DOI 10.1016/j.matlet.2005.05.047, PII S0167577X05005082;
Journal of Nanoparticle Research. 13(11):5705-5717.
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ABSTRACT: Conference code: 80810, Export Date: 17 April 2012, Source: Scopus, CODEN: MRSPD, Language of Original Document: English, Correspondence Address: Resta, V.; ENEA, Department of Advanced Physics Technology and New Materials (FIM), Brindisi Research Center, Strada Statale Appia, 72100 Brindisi, Italy, References: Shen, Y.-J., Lee, Y.-L., (2008) Nanotechnology, 19, p. 045602;
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ABSTRACT: Cited By (since 1996): 3, Export Date: 17 April 2012, Source: Scopus, Art. No.: 155302, CODEN: NNOTE, doi: 10.1088/0957-4484/20/15/155302, Language of Original Document: English, Correspondence Address: Fragouli, D.; NNL - National Nanotechnology Laboratory, INFM, CNR, Via Arnesano, Lecce 73100, Italy; email: despina.fragouli@unile.it, Chemicals/CAS: cadmium sulfide, 1306-23-6; carbon, 7440-44-0; thiol derivative, 13940-21-1, References: Duan, X., Huang, Y., Agarwal, R., Lieber, C.M., (2003) Nature, 421 (6920), p. 241;
Nanotechnology. 20(15).
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ABSTRACT: Cited By (since 1996): 2, Export Date: 17 April 2012, Source: Scopus, doi: 10.1166/jnn.2010.1861, Language of Original Document: English, Correspondence Address: Fragouli, D.; National Nanotechnology Laboratory of INFM-CNR, Via Arnesano Km 5, 73100 Lecce, Italy, References: Tessler, N., Medvedev, V., Kazes, M., Kan, S., Banin, U., (2002) Science, 295, p. 1506;
Journal of Nanoscience and Nanotechnology. 10(2):1267-1272.
