Prof. Zitoun's Lab
Head - Nanomaterials on Surfaces Lab
Prof. David Zitoun is a Senior Lecturer in the Department of Chemistry and a member of the Nano-Energy and Nano-Materials Center at the Bar-Ilan Institute of Nanotechnology and Advanced Materials (BINA).
He came to Bar-Ilan University from the University of Montpellier, France, as part of the 2008 cohort of returning scientists, a special program within Bar-Ilan University to recruit young Israeli scientists to return to work in Israel.
Nanotechnology and Materials: A Bottom-Up Approach to Devices
As miniaturization is spreading among all fields of technology, one key desired parameter is the control of nanoscale thin films of materials. Currently, most of the control processes are based on the use of physical deposition, which presents severe limitations due to the harsh conditions of temperature and pressure required.
In Zitoun's lab, the team is working to use wet chemistry deposition as an alternative to thin films. They are exploring two major approaches. The first consists of the colloidal synthesis of nanospheres and nanowires, which are spread on the substrate by wet coating. In the second approach, the molecular precursor is directly targeted to the substrate and reacts in situ.
Zitoun and his group synthesize reactive organometallic complexes and study the thermolysis, photolysis and chemical reduction of these complexes. The lab builds on Zitoun’s previous work, in which he demonstrated that designed reactive organometallic precursors could be decomposed to form metallic coatings.
This approach allows direct synthesis on the desired substrate, such as a metal or plastic, with the use of standard coating equipment and/or state of the art research equipment, such as Atomic Layer Deposition.
The aim of the laboratory is to elaborate active and passive components for devices. The advantages in the syntheses described above are that they lead to "clean surface" nanoparticles and tailored interfaces.
Zitoun and his group work on the integration of these nano-building blocks on silicon, one of the most well-known and promising materials for energy conversion (solar cells) and energy storage (lithium-ion batteries). As silicon’s surface is free of contaminants, the nanoparticles can either be used directly, or after the grafting a functional molecule on the surface, leading to hybrid materials.
One project conducted in Zitoun’s lab aims at elaborating a conductive transparent window based on a thin film of metallic nanowires. The ability to tailor the interfaces between the nanowires by molecular grafting enables precise control of the conductivity of the film.
In another project, the group synthesizes silicon nanowires by chemical etching, and engineers them as anodes for lithium-ion batteries with a one order of magnitude increase of weight capacity as compared to standard graphite. An additional research topic addressed by the lab is related to tuning the permeability of ferromagnetic thin films by adapting the chemical reactivity of organometallic precursors.
Complex alloys are usually mandatory for soft and hard magnets, and in this respect, the lab is working on nickel/iron/cobalt based alloys grown at very low temperature, and their self-assembly as nanodots, nanowires and nanoplates.
Looking to the Future: Intelligent Self-assembly for Better Devices
Zitoun and his group continue to work on projects related to the self-assembly of functional materials on the nanometer scale. Their initial work on this area was conducted on transparent conductive windows, anodes from lithium-ion batteries, and magnetic thin films, and they are currently working on applying their ideas to lithium-ion batteries and photovoltaic inorganic thin films.
Zitoun and his team plan to continue working on projects related to alternative energy sources, which they believe is a cornerstone to a brighter future.