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Righetto M, Bolzonello L, Volpato A, Amoruso G, Panniello A, Fanizza E, Striccoli M, Collini E. Deciphering hot- and multi-exciton dynamics in core-shell QDs by 2D electronic spectroscopies. Phys Chem Chem Phys 2018; 20:18176-18183. [PMID: 29961782 PMCID: PMC6044327 DOI: 10.1039/c8cp02574f] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
2D electronic spectroscopy maps acquired in different configurations unveil intraband hot carrier cooling and interband multi-exciton recombination dynamics.
Although the harnessing of multiple and hot excitons is a prerequisite for many of the groundbreaking applications of semiconductor quantum dots (QDs), the characterization of their dynamics through conventional spectroscopic techniques is cumbersome. Here, we show how a careful analysis of 2DES maps acquired in different configurations (BOXCARS and pump–probe geometry) allows the tracking and visualization of intraband Auger relaxation mechanisms, driving the hot carrier cooling, and interband bi- and tri-exciton recombination dynamics. The results obtained on archetypal core–shell CdSe/ZnS QDs suggest that, given the global analysis of the resulting datasets, 2D electronic spectroscopy techniques can successfully and efficiently dispel the intertwined dynamics of fast and ultrafast recombination processes in nanomaterials. Hence, we propose this analysis scheme to be used in future research on novel quantum confined systems.
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Affiliation(s)
- Marcello Righetto
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy.
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Pati ML, Fanizza E, Hager S, Groza D, Heffeter P, Laurenza AG, Laquintana V, Curri ML, Depalo N, Abate C, Denora N. Quantum Dot Based Luminescent Nanoprobes for Sigma-2 Receptor Imaging. Mol Pharm 2017; 15:458-471. [PMID: 29226684 DOI: 10.1021/acs.molpharmaceut.7b00825] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The increasing importance of sigma-2 receptor as target for the diagnosis and therapy of tumors paves the way for the development of innovative optically traceable fluorescent probes as tumor cell contrast and therapeutic agents. Here, a novel hybrid organic-inorganic nanostructure is developed by combining the superior fluorescent properties of inorganic quantum dots (QDs), coated with a hydrophilic silica shell (QD@SiO2 NPs), the versatility of the silica shell, and the high selectivity for sigma-2 receptor of the two synthetic ligands, namely, the 6-[(6-aminohexyl)oxy]-2-(3-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)propyl)-3,4-dihydroisoquinolin-1(2H)-one (MLP66) and 6-[1-[3-(4-cyclohexylpiperazin-1-yl)propyl]-1,2,3,4-tetrahydronaphthalen-5-yloxy]hexylamine (TA6). The proposed nanostructures represent a challenging alternative to all previously studied organic small fluorescent molecules, based on the same sigma-2 receptor affinity moieties. Flow cytometry and confocal fluorescence microscopy experiments, respectively, on fixed and living cancerous MCF7 cells, which overexpress the sigma-2 receptor, prove the ability of functionalized (QD@SiO2-TA6 and QD@SiO2-MLP66) NPs to be internalized and demonstrate their affinity to the sigma-2 receptor, ultimately validating the targeting properties conveyed to the NPs by sigma-2 ligand conjugation. The presented QD-based nanoprobes possess a great potential as in vitro selective sigma-2 receptor imaging agent and, consequently, could provide a significant impact to future theranostic applications.
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Affiliation(s)
- Maria Laura Pati
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro , Via Orabona 4, I-70125 Bari, Italy
| | - Elisabetta Fanizza
- Istituto per i Processi Chimico-Fisici-IPCF-SS Bari, Consiglio Nazionale delle Ricerche, c/o Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro , Via Orabona 4, 70125 Bari, Italy.,Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro , Via Orabona 4, I-70125 Bari, Italy
| | - Sonja Hager
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna , Borschkegasse 8a, A-1090 Wien, Austria
| | - Diana Groza
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna , Borschkegasse 8a, A-1090 Wien, Austria
| | - Petra Heffeter
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center of the Medical University, Medical University of Vienna , Borschkegasse 8a, A-1090 Wien, Austria
| | - Amelita Grazia Laurenza
- Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro , Via Orabona 4, I-70125 Bari, Italy
| | - Valentino Laquintana
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro , Via Orabona 4, I-70125 Bari, Italy
| | - Maria Lucia Curri
- Istituto per i Processi Chimico-Fisici-IPCF-SS Bari, Consiglio Nazionale delle Ricerche, c/o Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro , Via Orabona 4, 70125 Bari, Italy
| | - Nicoletta Depalo
- Istituto per i Processi Chimico-Fisici-IPCF-SS Bari, Consiglio Nazionale delle Ricerche, c/o Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro , Via Orabona 4, 70125 Bari, Italy
| | - Carmen Abate
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro , Via Orabona 4, I-70125 Bari, Italy
| | - Nunzio Denora
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro , Via Orabona 4, I-70125 Bari, Italy
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Di Mauro AE, Striccoli M, Depalo N, Fanizza E, Cano L, Ingrosso C, Agostiano A, Curri ML, Tercjak A. Selective confinement of oleylamine capped Au nanoparticles in self-assembled PS-b-PEO diblock copolymer templates. SOFT MATTER 2014; 10:1676-1684. [PMID: 24800269 DOI: 10.1039/c3sm52596a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Amphiphilic polystyrene-block-polyethylene oxide (PS-b-PEO) block copolymers (BCPs) have been demonstrated to be effective in directing organization of colloidal Au nanoparticles (NPs). Au NPs have been incorporated into the polymer and the different chemical affinity between the NP surface and the two blocks of the BCP has been used as a driving force of the assembling procedure. The morphology of the nanocomposites, prepared and fabricated as thin films, has been investigated by means of atomic force and scanning electron microscopies as a function of the NP content and BCP molecular weight. NPs have been effectively dispersed in PS-b-PEO hosts at any investigated content (up to 17 wt%) and a clear effect of the BCP properties on the final nanocomposite morphology has been highlighted. Finally, electrostatic force microscopy has demonstrated the conductive properties of the nanocomposite films, showing that the embedded Au NPs effectively convey their conductive properties to the film. The overall investigation has confirmed the selective confinement of the as-prepared surfactant-coated metal NPs in the PS block of PS-b-PEO, thus proposing a very simple and prompt assembling tool for nanopatterning, potentially suitable for optoelectronic, sensing and catalysis applications.
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Placido T, Fanizza E, Cosma P, Striccoli M, Curri ML, Comparelli R, Agostiano A. Electroactive layer-by-layer plasmonic architectures based on Au nanorods. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2608-2618. [PMID: 24564705 DOI: 10.1021/la402873c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Nanostructured films based on Au nanorods (NRs) have been obtained by layer-by-layer (LbL) assembly driven by electrostatic interaction between metal nanoparticles and polyelectrolytes. Multilayer films have been fabricated by using LbL assembly of poly(sodium styrenesulfonate) (PSS) and positively charged Au NRs on a polyelectrolyte-modified substrate. The effect of fabrication parameters, including the nature of the substrate, the polyelectrolyte initial anchoring layer, and the number of layers has been investigated by means of UV-vis absorbance spectroscopy and atomic force microscopy (AFM). The results demonstrated the dependence of morphology and plasmonic features in the multilayered nanostructured architectures from the nature of the anchoring polyelectrolyte on the substrate, the number of layers, and the kind of NR mutual assembly. In addition, a study of the electrochemical activity at the solid/liquid interface has been carried out in order to assess charge transport through the NR multilayer by using two molecular probes in solution, namely, potassium ferricyanide, a common and well-established redox mediator with reversible behavior, and cytochrome C, a robust model redox protein. The presented systematic study of the immobilization of Au NRs opens the venue to several application areas, such as (bio)chemical sensing.
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Affiliation(s)
- Tiziana Placido
- CNR-IPCF Istituto per i Processi Chimici e Fisici, Sez. Bari , c/o Dip. Chimica Via Orabona 4, 70126 Bari, Italy
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Sardella E, Liuzzi F, Comparelli R, Depalo N, Striccoli M, Agostiano A, Favia P, Curri ML. Functionalized luminescent nanocrystals on patterned surfaces obtained by radio frequency glow discharges. NANOTECHNOLOGY 2013; 24:145302. [PMID: 23507981 DOI: 10.1088/0957-4484/24/14/145302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this work a genuine combination of a bottom-up approach, which is based on synthesis and functionalization of emitting nanocrystals (NCs), with a top-down strategy, which relies on a flexible and versatile cold plasma process, is shown. Luminescent semiconducting colloidal NCs consisting of a CdSe core coated with a ZnS shell (CdSe@ZnS) are directly assembled onto micro-patterned substrates previously functionalized by means of glow discharges performed through physical masks. The NC assembly is driven by electrostatic interactions that led to their successful organization into spatially resolved domains. Two distinct protocols are tested, the former using a plasma deposition process combined with an electrostatic layer-by-layer procedure, the latter based on a two-step plasma deposition/treatment process. The procedures are thoroughly monitored with fluorescence microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy and scanning electron microscopy. The two-step plasma protocol is demonstrated to be more efficient in directing a uniform and specific assembly of luminescent NCs with respect to the hybrid procedure. The presented 'mix and match' approach offers great potential for integrating NCs, with their unique size-dependent properties, into microstructures, providing a universal platform for the fabrication of sensors, biochips, displays and switches.
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Affiliation(s)
- E Sardella
- CNR-IMIP (UOS Bari) c/o Dipartimento di Chimica, Università degli Studi di Bari, via Orabona 4, I-70126 Bari, Italy.
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Watanabe S, Mino Y, Ichikawa Y, Miyahara MT. Spontaneous formation of cluster array of gold particles by convective self-assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:12982-12988. [PMID: 22916823 DOI: 10.1021/la302811y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Cluster arrays composed of metal nanoparticles are promising for application in sensing devices because of their interesting surface plasmon characteristics. Herein, we report the spontaneous formation of cluster arrays of gold colloids on flat substrates by vertical-deposition convective self-assembly. In this technique, under controlled temperature, a hydrophilic substrate is vertically immersed in a colloid suspension. Cluster arrays form when the particle concentration is extremely low (in the order of 10(-6)-10(-8) v/v). These arrays are arranged in a hierarchically ordered structure, where the particles form clusters that are deposited at a certain separation distance from each other, to form "dotted" lines that are in turn aligned with a constant spacing. The size of the cluster can be controlled by varying the particle concentration and temperature while an equal separation distance is maintained between the lines formed by the clusters. Our technique thus demonstrates a one-step, template-free fabrication method for cluster arrays. In addition, through the direct observation of the assembly process, the spacing between the dotted lines is found to result from the "stick-and-slip" behavior of the meniscus tip, which is entirely different from the formation processes observed for the striped patterns, which we reported previously at higher particle concentrations. The difference in the meniscus behavior possibly comes from the difference in colloidal morphology at the meniscus tip. These results demonstrate the self-regulating characteristics of the convective self-assembly process to produce colloidal patterns, whose structure depends on particle concentration and temperature.
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Affiliation(s)
- Satoshi Watanabe
- Department of Chemical Engineering, Kyoto University, Katsura, Nishikyo, Kyoto, Japan
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