Our group targets many aspects of fundamental research in nanocrystals, ranging from the advanced synthesis, to assembly and to the study of chemical and structural transformations in nanomaterials. The applications that are the focus of our research span many disparate fields, including catalysis, energy storage, optoelectronics, and lighting. Also, in collaboration with other groups at IIT, we develop applications in biomedicine (for example laser hyperthermia), for photodetection, and removal of heavy metals from contaminated fluids.

Activities

The Electron Microscopy (EM) laboratory includes two scanning EMs (SEMs), both with analytical capabilities, one (JEOL JSM-6490LA) devoted to routine imaging even in low vacuum conditions and a high-resolution instrument (JEOL JSM-7500FA). The laboratory is also equipped with three transmission EMs (TEMs): one of them (JEOL JEM-1011) used for routine imaging and diffraction, one (FEI Tecnai G2 F20) optimized for cryo-electron tomography and a third one (JEOL JEM-2200FS, image-Cs-corrected) optimized for high-resolution TEM imaging and with in-situ capabilities (heating, electrochemical liquid cell, cryo). The laboratory also includes an area devoted to specimen preparation of both hard and soft materials in view of EM analysis. The whole instrumentation enables in-depth analyses of a huge variety of samples and processes.

The Advanced Characterization Facility provides structural and chemical analyses. The facility comprises a X-ray diffraction (XRD) laboratory equipped with two X-ray diffractometers.

A Rigaku Smartlab, with 9kW Cu Ka rotating anode and five axis high resolution goniometer is used for advanced X-ray diffraction measurements on a wide range of materials. Many accessories (doomed high temperature stage, capillary rotation attachment, XYZ automatic stage, D/teX Ultra SSD linear detector and battery cell attachment) are available for a large variety of measurements (e.g. non-ambient conditions and in-situ electrochemical analysis). Additionally, a PANalytical Empyrean system equipped with universal PreFIX optics, Pixcel3D2x2 area detector and programmable XYZ platform, is available for routine measurements. Moreover, the facility comprises a Photoelectron Spectroscopies lab, including a photoelectron spectrometer (Kratos UltraDLD) equipped for X-ray (XPS) and ultraviolet (UPS) spectroscopies, enabling for both core-levels and valence band investigations. The system is equipped with a temperature-controlled stage (working in the 77 – 870 K range) and with an Ar Gas Cluster Ion Source, for depth profiling studies.

Our studies are aimed at understanding the mechanisms underlying cation exchange reactions in nanocrystals. A cation exchange reaction is a post-synthetic chemical transformation in which the cations of a preformed nanocrystal are exchanged with new desired cations while preserving, in most cases, the size, shape and morphology of the starting nanocrystal. If only part of the original cations are substituted with guest ions, then alloy nanostructures or heterostructured nanocrystals are formed.

 

Engineering new nanomaterials by controlling the self-organization of colloidal nanocrystals is a versatile route to create sophisticated structures that can provide diverse functionalities. We work on the formation of well-ordered 2D monolayer – with a single or two types of component shapes - and 3D nano-solids, for which we study in detail the nanocrystal interactions for a better understanding of the mechanisms responsible for their self-assembly. Currently, our main focus is on multiply branched nanocrystals. We implement different experimental approaches to prepare hybrids with nanocrystals and polymers, and our target is that proper control over the interactions between the components play in favour of the self-organization of the particles in the films to enhance functionalities in the resulting material. We collaborate with other groups to develop molecular dynamics simulations that provide a complete analysis of the self-assembly of the nanocrystals and find the key parameters to control and optimize the structures.

In heterogeneous catalysis we target the development of innovative materials for the efficient exploitation of new energy feedstocks (i.e. methane and biomasses) and the effective conversion of CO2, in order to foster a sustainable carbon-based economy. We focus on nano-engineered, multi-element nanocrystals (i.e. nanoalloys and nano-scale mixed oxides), where synergistic effects in terms of electronic and structural interactions could lead to breakthrough results in the selected energy relevant catalytic processes.

Equipment

The laboratory of heterogeneous catalysis is equipped with state of the art equipment for the measurement of catalytic activity data the characterization of catalytic materials. The equipment includes different micro-reactors, able to work continuously and in parallel. Gas phase analysis at reactor outlet can be carried out using gas chromatography, mass spectrometry and non-dispersive infrared spectroscopy, enabling the study of both steady-state and transient reaction conditions. The laboratory is also equipped with instrumentation for physisorption and chemisorption measurements. By an in-house built set-up we can exploit a powerful technique (called concentration-modulation excitation spectroscopy) that allows to monitor the evolution of chemical species at the gas–solid interface by means of in situ Diffuse Reflectance Infrared Spectroscopy (DRIFTS).

Lead halide perovskites, in their bulk form, are emerging as one of the most promising materials for photovoltaic applications.  On the other hand, nanocrystals made of these materials show outstanding optical properties that could be exploited for bright inorganic dyes, lighting devices and lasers over the whole visible spectrum. In our group, we are working on new synthetic approaches towards colloidal methods by which we can finely control size, shape and composition of fully inorganic lead halide perovskite nanocrystals, in order to optimize their optical properties. The nanocrystals are then implemented in optoelectronic devices, also in collaboration with other research teams at IIT. Moreover, we are working at solving the Pb toxicity issue of these materials, either by testing alternative cations or by minimizing lead leaching by surface engineering

Hydrogen has drawn considerable attention as an efficient alternative energy carrier to fossil fuels, due to its clean and renewable characteristics. Since the first report on photocatalytic water splitting with TiO2 as photoanode by Fujishima and Honda in 1972, the generation of hydrogen utilizing simple and inexpensive procedures has received increasing attention. The PEC water splitting process uses semiconductor materials to convert solar energy directly to chemical energy in the form of hydrogen. The semiconductor materials used in the PEC process are similar to those used in photovoltaic solar electricity generation, but for PEC applications the semiconductor is immersed in a water-based electrolyte, where sunlight energizes the water-splitting process. Our group has recently started working on the synthesis, characterization and applications of novel colloidal nanocrystals based on SnS, SnSe, SnSe2 and NiS by hot injection and ion-exchange reactions that could be used for electro and photocatalytic water splitting, with the final aim to efficiently generate hydrogen.

The use of nanosized particles in Lithium and Sodium–ion batteries can alleviate the issues related with poor ionic and electronic conductivity associated with many materials that can intercalate such ions, thus helping to develop high-rate performing electrodes. The Battery activity comprises the synthesis and the morphological, structural and electrochemical characterization of nanosized crystals, in view of their application as electrodes in Lithium-ion and Sodium-ion batteries. In collaboration with Graphene Labs the combined use of graphene and nanosized crystals is even explored as an alternative way to improve electronic conductivity and enhance the electrodes rate performances. Coin-cell type batteries are assembled in a Argon filled glove-box with oxygen and water levels < 0.1 ppm, to prevent both the Li or Na metal oxidation and the electrolyte degradation. Multi-channel Potentiostats/galvanostats are used to test the electrochemical performances via cyclic voltammetry, impedance spectroscopy and galvanostatic charge/discharge cycles.

Degenerately doped semiconductor NCs show tunable localized surface plasmon resonances (LSPRs), which can be tuned over a wide spectral range from the vis to the NIR by controlling the carrier density. In copper chalcogenide NCs this occurs by controlling the copper vacancy density by post-chemical treatment; in contrast in doped metal oxide NCs upon capacitive charging via electrochemical or photo doping. These fundamentally different mechanisms of plasmon tuning result in diverse applications, such as sensing, heavy metal detection, photocatalysis or to trigger chemical reactions.

We have recently initiated a research line aimed at screening different nanocrystal materials that have a significant absorption in the NIR “water window” region, where the light can penetrate deep into biological tissues. We develop synthesis for these materials, we study their optical and structural properties and we attempt to correlate the laser heating efficiency with their electronic structure, also using computational approaches. Then, in collaboration with the D3 Department at IIT we functionalize the surface of these nanocrystals to make them stable in biological media and study their photothermal effect on various cell lines.

Projects

  1. SAN PAOLO (contract n. 2008.2381) - Coordinated by Università; di Siena.
    Molecular and morphological correlates of neuronal plasticity in rat models of learning
    Person in charge for IIT: A. Falqui. IIT Contribution: €60.000. Project start: July 1st 2009. End: June 30th 2012.
  2. FP7 Collaborative Project (MAGNIFYCO, contract n. 228622) - Coordinated by CNR-Lecce.
    Magnetic Nanocontainers for combined hyperthermia and controlled drug release
    Person in charge for IIT: L. Manna and T. Pellegrino. IIT Contribution: €327.720. Project start: September 1st 2009. End: February 28th 2013.
  3. FP7 ERC Starting Grant (NANO ARCH contract n. 240111).
    Assembly of Colloidal Nanocrystals into Unconventional Types of Nanocomposite Architectures with Advanced Properties
    Person in charge for IIT: L. Manna. IIT Contribution: €1.299.960. Project start: September 1st 2009. End: February 28th 2013.
  4. FP7 Collaborative Project (SCALENANO contract n. 284486) - Coordinated by IREC.
    Development and scale-up of nanostructured based materials and processes for low cost high efficiency chalcogenide based photovoltaics
    Person in charge for IIT: L. Manna; IIT Contribution: €305.400. Project start: February 1st 2009. End: July 31st2015.
  5. FIRB (Italian funds for fundamental research) project (contract n. RBAP115AYN) - Coordinated by Università degli Studi di Milano Bicocca.
    Ossidi nanostrutturati: multi-funzionalità e applicazioni
    Person in charge for IIT: L. Manna - IIT Contribution: €226.160. Project start: February 22nd 2012. End: February 21st 2015.
  6. FP7 Marie Curie Intra European Fellowship (IEF) NIRPLANA (contract n. 298022).
    Near-Infrared Semiconductor Plasmonic Nanocrystals for Enhanced Photovoltaics
    Person in charge for IIT: I. Moreels. IIT Contribution: €193.726,80. Project start: May 16th 2012. End: May 15th 2014
  7. FP7 Marie Curie Intra European Fellowship (IEF) LOTOCON (contract n. 301100).
    Low-toxicity copper chalcogeneide semiconductor nanocrystals
    Person in charge for IIT: V. Lesnyak. IIT Contribution: €185.763,60. Project start: June 15th 2012. Ended: June 14th 2014
  8. FP7 Marie Curie Actions Initial Training Networks (ITN) - Coordinated by Universitaet Regensburg.Mag(net)icFun (contract n. 290248)
    Functionalized Magnetic Nanoparticles and their Application in Chemistry and Biomedicine
    Person in charge for IIT: L. Manna and T. Pellegrino. IIT Contribution: €590.234. Project start: October 1st 2012. End: September 30th 2016
  9. CARIPLO 2012 NANOCRYSLAS (contract n. 2012-0824).
    Micro-laser based on rod-shaped self-assembling colloidal semiconductor nanocrystals
    Person in charge for IIT: R. Krahne. IIT Contribution: €74.000. Project start: March 1st 2013. End: February 28th 2015
  10. FP7 Collaborative Project FLAGSHIP GRAPHENE (contract n. 604391)
    Graphene-Based Revolutions in ICT And Beyond
    Person in charge for NACH dep.: L. Manna, R. Krahne and I. Moreels. NACH Contribution: €305.520. Project start: October 1st 2013. End: March 31st 2016
  11. AIRC Investigator Grant (contract n. IG 14527)
    Stimuli-Responsive Nanoparticles for eradicating different subsets of cancer cells within tumors
    Person in charge for IIT: T. Pellegrino. IIT Contribution: €180.000. Project start: January 2nd 2014. End: January 1st 2016
  12. FP7 ERC Consolidator Grant TRANS NANO (contract n. 614897).
    Advancing the Study of Chemical, Structural and Surface Transformations in Colloidal Nanocrystals
    Person in charge for IIT: L. Manna. IIT Contribution: €2.430.720. Project start: March 1st 2014. End: February 28th 2019
  13. CARIPLO 2013 - Coordinated by Istituto Nazionale Tumori (contract n. 2013 0865).
    Disease recurrence in epithelial ovarian cancer: deciphering miRNA-driven regulatory networks related to drug sensitivity/cellular plasticity and exploring nanomaterial-based targeted delivery of identified key molecules for therapeutic purposes
    Person in charge for IIT: T. Pellegrino. IIT Contribution: €90.000. Project start: May 1st 2014. Project end: April 30th 2017
  14. CARIPLO 2013 GREENS(contract n. 2013 0656).
    Green nanomaterials for next-generation photovoltaics
    Person in charge for NACH dep.: L. Manna. NACH Contribution: €140.000. Project start: June 1st 2014. End: May 31st 2016