Contact Persons: Maria Losurdo

Keywords: Plasma Deposition, Plasma Processing, Surface Functionalization, Processes Development, Materials Growth, Nanostructures, Biomaterials, Coatings

Plasmas are used to deposit or remove/etch materials and nanostructures in a controlled way making possible intricate patterns on a large variety of substrates, including wafers of silicon for microelectronic, glass, ceramics and plastics. Plasma-aided fabrication is an integral part of electronics and semiconductor manufacturing. It is used in the manufacturing of everyday devices such as computer processors, RAM, hard drives, monitors, television displays, and solar cells. Progress in plasma research has proved essential to the rapid miniaturization and increased performance of electronics.

Plasma-surface interaction processes are investigated predominantly in dedicated laboratory experiments and the understanding of these interactions is used to develop new technologies with far-reaching applications as well as  to endow solid surfaces and materials with new functionalities. Plasma at room temperature and atmospheric pressure is used in biotechnology and medicine to sterilize surgical equipment, to disinfect clothing or surfaces and to modify cellular growth. Its antibacterial and antimicrobial properties also mean it can be used for wound care. Initial research into cold plasma applications has explored their uses in medicine, particularly for infection control and cancer therapy. Plasma research is also dedicated to the potential uses of the antimicrobial properties of cold plasma in agriculture and food for livestock healthcare and biosecurity, food hygiene and shelf-life extension. The plasma technology has the ability to reduce harmful chemicals and antibiotics in the food chain. Plasmas are also applied to environmental science and engineering, including contaminated soil and wastewater remediation, metal recovery from waste solutions, sterilization and air pollutant abatement.

We provide a balanced and comprehensive expertise in the core principles, novel plasma reactors and diagnostics, and state-of-the-art environmental applications of plasma.

The research lines of the PlasmaChem area are listed below:

  1. Plasma for Materials
  2. Plasma Medicine
  3. Plasma AgriFood
  4. Plasma for Environment & Energy
  5. Plasma Architectures

Plasma for Materials
Contact Persons: Maria Losurdo

Keywords: Semiconductors, Oxides, Ceramics, Perovskites, Graphene and 2D Materials, Metal Nanoparticles, Nanostructures, Scaffolds

People: Maria Losurdo, Maria Michela Giangregorio, Giovanni Bruno, Giuseppe Bianco, Fabio Palumbo, Fiorenza Fanelli, Eloisa Sardella, Silvia Colella, Marcella Dell’Aglio, Alberto Sacchetti, Savino Cosmai, Andrea Listorti, Francesco Fracassi, Pietro Favia, Alessandro De Giacomo, Fabio Arnesano, Marco Grande, Gerardo Palazzo.

Plasma material engineering embraces a large range of processes aimed at tailoring properties of materials during their growth/deposition and at drastically changing the surface properties of materials preserving the bulk ones. This includes for instance corrosion protective coatings, barrier layers for food packaging, surface hydrophobization/hydrophilization, enhanced surface dyebility/printability or adhesion. In particular plasma-assisted deposition can be used to produce films on a solid material by promoting chemical reactions at the plasma/substrate interface. Indeed, by using sacrificial layers/substrates free standing nano-films can be produced. The processes can be performed by using both low and atmospheric pressure plasmas in direct and remote approach, injecting the film precursors in gas, vapor and aerosol form. Strategies differ depending on the addressed surface property. Barrier and protective coatings consist in inorganic film (SiOx or SiNx) commonly deposited from organosilicon fed plasmas. The control of polymer adhesion properties and alike (dyebility) can be reached by grafting of polar groups (oxygen or nitrogen containing ones) in plasma fed with O2, N2 or H2O. Hydrophobization can be achieved either by PECVD of fluorocarbon and organosilicon coatings or by grafting of F-contaning functionalities (e.g., CF4-fed plasma).

Plasma Medicine
Contact Persons: Eloisa Sardella

Keywords: Plasma Medicine, Plasma Pharmacy, Plasma Induced Oxidative Stress, Plasma Immunotherapy

People: Eloisa Sardella, Roberto Gristina, Pietro Favia.

Plasma medicine is an interdisciplinary field of research that studies the direct application of cold atmospheric plasma (CAP) on or inside the human body for therapeutic purposes. Over the past decade, plasma medicine has shown promising applications in sterilization, wound healing, dentistry, tissue engineering and cancer therapy. Approaches to plasma medicine include: direct plasma treatment of cells in the presence or not of liquid media and plasma treatment of liquid solutions for secondary application to cells (indirect approach). The study of chemical composition of plasma treated water solutions (PTWS), beside their importance to gain new insights in mechanism of action of direct approaches, offers important advancement towards an emerging field known as Plasma Pharmacy, i.e. the systemic administration of PTWS for therapeutic treatment of patient diseases. The observed behaviors of cells exposed to PTWS were presumably due to Reactive Oxygen and Nitrogen Species (RONS) considered as main players of the process. Currently, the mechanism of PTWS is mainly linked to the presence of H2O2, but PTWS are more than an H2O2 solution, because their effect is larger than an H2O2 solution at the same concentration, indicating that it is the chemical cocktail of species that induces selective cancer cell death. Oxidative stress caused by the imbalance between the excessive formation of RONS and limited antioxidant defenses apart from cancer is connected to other pathologies including age-related disorders, cardiovascular, inflammatory, and neurodegenerative diseases such as Parkinson’s and Alzheimer’s diseases. Plasma treated water solutions (PTWS) are well known as possible sources of RONS for triggering specific cell responses that are tightly related to the chemical composition of the tested liquids. Working with PTWS has some extra value above direct plasma treatment, for tumors inside the body, which are not easily accessible by direct CAP treatment. NANOTEC, thanks to a tight collaboration with the Istituto Tumori Bari Giovanni Paolo II - IRCCS has demonstrated for the first time in literature the possibility to induce Immunological Cell Death (ICD) of tumor cells mediated by the PTWS by opening the scenario of using such activated solution not only as a type of cancer chemotherapy but also as a way to help dendritic cells find, eat and present cancer cell antigen to elicit robust T cell immune responses (i.e. redox-control T cell phenotypes in cancer immunology). Moreover, the expertize of the NANOTEC team involved in this research allowed to gain important insights on the role of Reactive Nitrogen containing species (RNS) in combination with H2O2 when the level of the latter is below the damaging level for nonmalignant cells. Finally, this line of research is offering today very interesting results on other cell models demonstrating an improvement of the glial cell migration depending on the chemical composition of PTWS as a tool to support wound healing in brain diseases.

Plasma AgriFood
Contact Persons: Fabio Palumbo

Keywords: Hitech Agricolture, Healthy Food, Food Packaging, Plasma Activated Water, Seeds Treatment

People: Fabio Palumbo, Pietro Favia, Eloisa Sardella, Fiorenza Fanelli, Maria Losurdo

Application of plasma technology to the agriculture field has gained interest in the last 10 years. In fact this technique is suitable for treatment of biological samples, operating approximately at room temperature and pressure. The technology is considered environmentally friendly as systems can be designed to operate with atmospheric air only, and the process does not produce waste. The research is oriented to address mainly the following applications: Decontamination of seeds; Decontamination of plants; Enhancement of seed germination; Disinfection of products before packaging; Treatment, sterilization, and cleaning of water used for washing products after harvest; Treatment of water to add reactive reactive species combined with lowered pH, to reduce pathogen proliferation in soil; Capture of atmospheric nitrogen in water to be used as fertilizer. The main strategies carried out at NANOTEC are mostly: Plasma treatment at atmospheric pressure of seeds to enhance germination and reducing pathogens. Plasma treatment to activate water to be used in watering to reduce pathogens in soils, and helping nitrogen fixation. Plasma coating of seed with active nanocomposite films to reduce pathogens proliferation and enhancing germination. Sanitising microbiologically contaminated soil and soilless growth substrates, where plasma can destroy unwanted microbial cells whilst retaining fertility of the soil and substrates Plant disease management, by direct plasma treatment as well as PAW generating reactive oxygen and nitrogen species that, combined with lowered pH, control plant pathogens. Fresh fruits/vegetables disinfection before packaging and disinfection of packaged fruits, sealed in plastic or cellophane.

Plasma for Environment & Energy
Contact Persons: Fiorenza Fanelli

Keywords: Plasma Surface Eingineering, Water Condensation, Water Harvesting, Photocatalysis, air Decontamination, Hybrid Perovskite Solar Cells

People: Fiorenza Fanelli, Fabio Palumbo, Silvia Colella, Andrea Listorti, Francesco Fracassi, Savino Cosmai, Maria Losurdo.

Our objective here is the exploitation of non-equilibrium plasma technologies for various applications in the field of energy, environmental protection and remediation. Research topics currently include: Plasma processing of filtration and absorbent materials for oil/water separation, characterized by extremely opposite wetting behavior towards oil and water. Plasma deposition of photocatalytic thin films, containing metal oxides as TiO2, Fe2O3 and ZnO, for the degradation of organic pollutants in water and for water splitting. Surface modification of adsorbent materials for removal of heavy metal and organic pollutants from aqueous solutions. Interface engineering of hybrid halide perovskite based photovoltaic devices using advanced plasma technologies. Development of novel surfaces for efficient water harvesting and condensation. Atmospheric pressure plasma treatment of air and water for abatement of pollutants, decontamination and disinfection.

Plasma Architectures
Contact Persons: Giovanni Bruno, Marcella Dell’Aglio (Laser-Plasma)

Keywords: Low-pressure Plasms, Atmospheric Plasmas, Radiofrequency Plasmas, Sputtering, Dielectric Barrier Discharges, Remote Plasms, Laser-Plasma

People: Giovanni Bruno, Fabio Palumbo, Fiorenza Fanelli, Savino Cosmai, Alberto Sacchetti, Francesco Fracassi, Maria Losurdo, Marcello Dell’Aglio, Alessandro De Giacomo, Fabio Arnesano, Gerardo Palazzo.
Low pressure and atmospheric pressure plasma

The strong expertise in plasma deposition and plasma treatment processes of materials has given Bari-unit the chance to take a leading position also on Plasma Reactors Architecture. Since the 1980s, plasmochemical reactors have been developed for the deposition of materials (semiconductors and related materials, oxides, polymers) for the modification and activation of surfaces, and for etching of semiconductors. When in presence of complex processes the reactor engineered platform involves the careful assembling of plasma/surface characterization techniques also operating in real time. Low pressure plasma reactor design involves matching of sample/chamber size, gas flow rate/pumping speed, electrodes potential distribution and power sources. Furthermore, often heating/chilling of electrodes or substrates is necessary, as well as bias, to control surface ion bombardment. Technologies implemented by plasmas are: PECVD, remote plasma MOCVD, sputtering, etching, plasma MBE.
Atmospheric pressure dielectric barrier discharge reactors for surface treatment of materials need a smart design, assembly and optimization. Reactors design and electrode configurations are tailored to address the requirements of specific plasma processes (e.g., deposition of thin films from precursors in vapor or aerosol form) and, importantly, the shape and dimension of the substrate to be treated. Atmospheric pressure reactors include also plasma jets, i.e., remote plasma sources in which the plasma is allowed to exit from the region where it is generated and to propagate in the external environment towards the substrate to be treated. In order to improve the control of the surface/material modification/growth and for the understanding of the plasmachemistry mechanisms, the following techniques can be integrated in the reactor configuration: optical emission spectroscopy (OES), mass spectrometry (MS), Langmuir probe (LP), Laser reflectance interferometry (LRI) and spectroscopic ellipsometry (SE).

The following images summarize a few examples of types of plasma-reactor architectures in use and developed since 1980:

Laser Plasma

Laser Induced Plasma (LIP) is the plasma produced by laser-matter interactions, when a laser pulse with an irradiance of 0.1-10 GW cm2 is focused on a sample (solid, liquid or gas). In the last 3 decades, as a consequence of the decreasing cost of laser sources, the interest in LIP based technology is growing in analytical and material sciences. The most common applications are related to LIP based spectroscopy and spectrometry, industrial processes (welding, cutting etc.), production of thin films and nanostructures. In the laser plasma NANOTEC lab the applications are the following: 1) Spectroscopic diagnostics of Laser Induced Plasma (LIP) processes; 2) Chemical Analysis of solids, liquids and gases with Laser Induced Breakdown Spectroscopy (LIBS) (archaeological finding, meteorites, gemstones, soils and plants, sample submerged in water, etc.); 3) Nanoparticle field enhancement effect on laser induced plasma (NE-LIBS) for chemical analysis; 4) Nanoparticles and nanostructures production by Pulsed Laser Ablation in Liquids (PLAL) and their employment in different fields (analytical chemistry, biochemistry, etc.).