RESEARCH THEMES
Our research group focuses on four main themes:
- Sustainable energy harvesting: Focus on thermoelectric energy conversion and solid-state approaches for waste-heat recovery and energy efficiency.
- Nanomaterials and nanocomposites: Synthesis and characterization of inorganic and organic nanomaterials/nanocomposites, for energy, electronic, and functional applications.
- Surface and interface engineering: Tuning material properties by controlling nano- and micro-scale morphology and through targeted chemical functionalization of surfaces and interfaces.
- Additive manufacturing of advanced materials: Development of printable materials and manufacturing strategies, with particular focus on flexible, stretchable, and wearable devices and biomedical sensors.
Examples of Our Research Projects
● Efficient Conversion of Waste Heat to Electricity through Nano-Engineered Thermoelectric Materials
Our energy systems are predominantly powered by fossil fuels, producing CO₂ and other greenhouse gases that drive global climate change. A major shift toward sustainable energy sources is therefore essential. One promising solution is the conversion of waste heat into electricity using thermoelectric (TE) materials, which can directly transform a temperature gradient into electrical energy without generating additional pollution. To enhance this energy conversion efficiency, we focus on nano-engineering of TE materials, applying techniques such as nanostructuring, hybridization with nanoparticles, and the formation of nanoprecipitates. Our research emphasizes near-room temperature chalcogenide materials, including Bi-Te, Bi-Se, Sb-Te, and their ternary alloys, compounds, and composites.
Our energy systems are predominantly powered by fossil fuels, producing CO₂ and other greenhouse gases that drive global climate change. A major shift toward sustainable energy sources is therefore essential. One promising solution is the conversion of waste heat into electricity using thermoelectric (TE) materials, which can directly transform a temperature gradient into electrical energy without generating additional pollution. To enhance this energy conversion efficiency, we focus on nano-engineering of TE materials, applying techniques such as nanostructuring, hybridization with nanoparticles, and the formation of nanoprecipitates. Our research emphasizes near-room temperature chalcogenide materials, including Bi-Te, Bi-Se, Sb-Te, and their ternary alloys, compounds, and composites.
● Flexible and Wearable Nano-Thermoelectrics for Body Energy Harvesting
Thermoelectric research has traditionally concentrated on rigid devices, with limited exploration of flexible power generators. But recently, there have been efforts to address that gap by using nanotechnology and additive manufacturing to create compact, flexible thermoelectric devices that can be worn on the skin or integrated into clothing to harvest ambient body heat and convert it to electricity. We develop functionalized inks containing conductive polymers and semiconducting nanomaterials to print flexible thermoelectric films, and flexible thermoelectric generators. These cost-effective, miniaturized generators hold potential to replace battery-based systems in wearable electronics and sensors that require power levels in the µW–mW range. Their advantages include self-sustainability, motionless electricity generation (without moving parts), and compatibility with wearable and medical devices, positioning this research at the forefront of next-generation wearable electronics.
Thermoelectric research has traditionally concentrated on rigid devices, with limited exploration of flexible power generators. But recently, there have been efforts to address that gap by using nanotechnology and additive manufacturing to create compact, flexible thermoelectric devices that can be worn on the skin or integrated into clothing to harvest ambient body heat and convert it to electricity. We develop functionalized inks containing conductive polymers and semiconducting nanomaterials to print flexible thermoelectric films, and flexible thermoelectric generators. These cost-effective, miniaturized generators hold potential to replace battery-based systems in wearable electronics and sensors that require power levels in the µW–mW range. Their advantages include self-sustainability, motionless electricity generation (without moving parts), and compatibility with wearable and medical devices, positioning this research at the forefront of next-generation wearable electronics.
● Electrospinning for Advanced Biomedical Sensors & Energy Harvesting Fabrics
Electrospinning is a powerful and versatile technique for creating nanofibers with tailored mechanical, thermal, and electrical properties, enabling breakthroughs across a range of biomedical and wearable technologies. In our research, electrospinning is used to develop flexible strain sensors for respiratory monitoring, where lightweight, stretchable nanofibers can comfortably conform to the chest or abdomen to precisely track breathing patterns. Additionally, electrospun thermoelectric nanofibers are employed in advanced cooling devices for treating injuries and managing chronic conditions, offering controlled, long-lasting cooling without the limitations of traditional methods. Lastly, electrospinning supports the creation of energy-harvesting fabrics capable of converting body heat into electricity, paving the way for self-powered wearable electronics. These diverse applications highlight electrospinning's potential in next-generation healthcare, monitoring, and sustainable energy technologies.
Electrospinning is a powerful and versatile technique for creating nanofibers with tailored mechanical, thermal, and electrical properties, enabling breakthroughs across a range of biomedical and wearable technologies. In our research, electrospinning is used to develop flexible strain sensors for respiratory monitoring, where lightweight, stretchable nanofibers can comfortably conform to the chest or abdomen to precisely track breathing patterns. Additionally, electrospun thermoelectric nanofibers are employed in advanced cooling devices for treating injuries and managing chronic conditions, offering controlled, long-lasting cooling without the limitations of traditional methods. Lastly, electrospinning supports the creation of energy-harvesting fabrics capable of converting body heat into electricity, paving the way for self-powered wearable electronics. These diverse applications highlight electrospinning's potential in next-generation healthcare, monitoring, and sustainable energy technologies.
● Synthesis and Electron Microscopy Characterization of 1D & 2D Boron Nitride Nanostructures
Boron nitride (BN) is a synthetically produced compound that does not occur naturally. It is isostructural to carbon, with hexagonal BN (h-BN) being a layered material similar to graphite. However unlike graphite, the controlled synthesis of pure, highly crystalline BN nanostructures remains a complex challenge, often resulting in low yields across methods. To address this, we developed a straightforward chemical vapor deposition (CVD) route for synthesizing high-quality BN nanostructures, including planar, tubular, and conical forms (such as nanosheets, nanotubes, and nanocones). To understand the growth mechanisms of these structures, we conducted systematic electron microscopy studies (HRTEM, STEM, SEM, EELS, EDX) on a wide range of BN nanostructures, identifying distinct growth mechanisms in each case.
Boron nitride (BN) is a synthetically produced compound that does not occur naturally. It is isostructural to carbon, with hexagonal BN (h-BN) being a layered material similar to graphite. However unlike graphite, the controlled synthesis of pure, highly crystalline BN nanostructures remains a complex challenge, often resulting in low yields across methods. To address this, we developed a straightforward chemical vapor deposition (CVD) route for synthesizing high-quality BN nanostructures, including planar, tubular, and conical forms (such as nanosheets, nanotubes, and nanocones). To understand the growth mechanisms of these structures, we conducted systematic electron microscopy studies (HRTEM, STEM, SEM, EELS, EDX) on a wide range of BN nanostructures, identifying distinct growth mechanisms in each case.
● Surface Engineering of Biomimetic Hierarchical Nanostructured Films towards Self-Cleaning and Water Treatment Applications
BN has excellent thermal stability, mechanical stiffness, and chemical inertness. This makes it an ideal material for surface protective film applications. So, we focused on the surface engineering of BN nanostructure films to control their wettability via two distinct approaches: (1) controlling the surface nanomorphology during the CVD synthesis; and (2) addition of functional groups to the surface by wet chemistry, plasma, and UV/ozone treatments. We initially grew a smooth BN film that was relatively hydrophilic with a water contact angle (CA) of ~50°. Then, by changing synthesis conditions, we grew partially and fully aligned boron nitride nanosheets vertical-to-substrate, which demonstrated hydrophobic (CA ~100°) and superhydrophobic effects (CA ~160°), respectively. Later we synthesized other hierarchical BN surfaces composed of aligned or randomly oriented nanotubes and nanocones, and observed similar water-repelling effects due to partial liquid/solid contact at the interface of those nano-rough surfaces. We also performed a DFT simulation to compare wetting on a flat and rough BN surface, and showed that the hydrophobicity extent and water CA of each BN film was a result of the interplay between two factors: (1) dipole moment interactions of polar water molecules and BN surfaces (dictated by the orientation of BN atomic layers on the surface); (2) real area of contact at the interface of water droplet and BN nanostructure (dictated by shape, size, and morphology).
BN has excellent thermal stability, mechanical stiffness, and chemical inertness. This makes it an ideal material for surface protective film applications. So, we focused on the surface engineering of BN nanostructure films to control their wettability via two distinct approaches: (1) controlling the surface nanomorphology during the CVD synthesis; and (2) addition of functional groups to the surface by wet chemistry, plasma, and UV/ozone treatments. We initially grew a smooth BN film that was relatively hydrophilic with a water contact angle (CA) of ~50°. Then, by changing synthesis conditions, we grew partially and fully aligned boron nitride nanosheets vertical-to-substrate, which demonstrated hydrophobic (CA ~100°) and superhydrophobic effects (CA ~160°), respectively. Later we synthesized other hierarchical BN surfaces composed of aligned or randomly oriented nanotubes and nanocones, and observed similar water-repelling effects due to partial liquid/solid contact at the interface of those nano-rough surfaces. We also performed a DFT simulation to compare wetting on a flat and rough BN surface, and showed that the hydrophobicity extent and water CA of each BN film was a result of the interplay between two factors: (1) dipole moment interactions of polar water molecules and BN surfaces (dictated by the orientation of BN atomic layers on the surface); (2) real area of contact at the interface of water droplet and BN nanostructure (dictated by shape, size, and morphology).
● Aluminum Micro-/Nano-Composites: Casting, Solid-State Sintering, Deformation, and Fracture Analysis
There have been many investigations on metal matrix microcomposites produced by conventional casting routes; however, in the past decade, the focus has shifted more toward nanocomposites produced via solid state routes. To have a realistic view of performance prediction and optimum design of such composites, in this work Al matrix composites (AMCs) reinforced with WC microparticles, nanoparticles, and bimodal micro-/nano-particles were prepared by spark plasma sintering. The effects of particle size and concentration, and process variables (i.e. sintering temperature, duration, and pressure) on the evolution of microstructure, density and hardness of the composites were studied comprehensively.
Then in the next step, composites of a Al reinforced with 10 wt% B4C microparticles were fabricated by a combination of spark plasma sintering and stir casting methods, followed by hot extrusion. A systematic study on the relationship between extrusion process variables (i.e. extrusion ratio, temperature, and punch speed) and porosity, particle refinement, particle distribution and consequently tensile properties and fracture behavior of the composites was performed. Extensive electron microscopy analysis and tensile testing of the composites revealed a multifactoral interdependency of microstructural evolution and mechanical properties on the extrusion process variables. For example, while increasing the extrusion ratio at higher temperatures led to moderate particle refinement, better densification of the composites, and improvement in mechanical properties, concurrent particle fragmentation and microvoid formation around the particles at lower temperatures had opposing effects on the mechanical behavior.
There have been many investigations on metal matrix microcomposites produced by conventional casting routes; however, in the past decade, the focus has shifted more toward nanocomposites produced via solid state routes. To have a realistic view of performance prediction and optimum design of such composites, in this work Al matrix composites (AMCs) reinforced with WC microparticles, nanoparticles, and bimodal micro-/nano-particles were prepared by spark plasma sintering. The effects of particle size and concentration, and process variables (i.e. sintering temperature, duration, and pressure) on the evolution of microstructure, density and hardness of the composites were studied comprehensively.
Then in the next step, composites of a Al reinforced with 10 wt% B4C microparticles were fabricated by a combination of spark plasma sintering and stir casting methods, followed by hot extrusion. A systematic study on the relationship between extrusion process variables (i.e. extrusion ratio, temperature, and punch speed) and porosity, particle refinement, particle distribution and consequently tensile properties and fracture behavior of the composites was performed. Extensive electron microscopy analysis and tensile testing of the composites revealed a multifactoral interdependency of microstructural evolution and mechanical properties on the extrusion process variables. For example, while increasing the extrusion ratio at higher temperatures led to moderate particle refinement, better densification of the composites, and improvement in mechanical properties, concurrent particle fragmentation and microvoid formation around the particles at lower temperatures had opposing effects on the mechanical behavior.
Research Collaborators & Visitors (past & present)
Prof. Dmitry Golberg, Queensland University of Technology (Australia)
Prof. Yoshio Bando, University of Wollongong (Australia)
Prof. Gunther Andersson, Flinders University (Australia)
Prof. Chunyi Zhi, City University of Hong Kong (China)
Prof. Xuebin Wang, Nanjing University (China)
Prof. Yanming Xue, Hebei University of Technology (China)
Prof. Gaulthier Rydzek, Université de Montpellier & CNRS (France)
Prof. Franck Gascoin, École Nationale Supérieure d'Ingénieurs de Caen & CNRS (France)
Prof. Sylvie Hebert, École Nationale Supérieure d'Ingénieurs de Caen & CNRS (France)
Prof. Florent Pawula, Université de Bordeaux (France)
Prof. Anthony Robinson, Trinity College Dublin (Ireland)
Prof. Tim Persoons, Trinity College Dublin (Ireland)
Prof. Rocco Lupoi, Trinity College Dublin (Ireland)
Prof. Seamus O'Shaughnessy, Trinity College Dublin (Ireland)
Prof. Jonathan Coleman, Trinity College Dublin (Ireland)
Prof. Michael Morris, Trinity College Dublin (Ireland)
Prof. Valeria Nicolosi, Trinity College Dublin (Ireland)
Prof. Roger West, Trinity College Dublin (Ireland)
Dr. Niall McEvoy, Trinity College Dublin (Ireland)
Dr. Aran Rafferty, Trinity College Dublin (Ireland)
Prof. Dario Narducci, University of Milano Bicocca (Italy)
Prof. Takao Mori, National Institute for Materials Science (Japan); University of Tsukuba (Japan)
Prof. Katsuhiko Ariga, National Institute for Materials Science (Japan); University of Tokyo (Japan)
Prof. Takashi Sekiguchi, National Institute for Materials Science (Japan); University of Tsukuba (Japan)
Dr. Mohamed B. Zakaria, National Institute for Materials Science (Japan); Waseda University (Japan)
Prof. Dayangku Noorfazidah Awang Shri, University of Malaysia Pahang (Malaysia)
Prof. Karina Vink, University of Twente (the Netherlands)
Prof. Agnieszka Witecka, Polish Academy of Sciences (Poland)
Prof. Dmitry V. Shtansky, National University of Science and Technology (Russia)
Prof. Andres Cantarero Saez, University of Valencia (Spain)
Dr. Andrés Seral-Ascaso, Instituto de Nanociencia y Materiales de Aragón (Spain)
Dr. Sang-Hoon Park, Korea Institute of Energy Research (South Korea)
Dr. John C.F. Zhang, EMPA- Swiss Federal Laboratories for Materials Science and Technology (Switzerland)
Prof. James Ryan, Swansea University (UK)
Dr. Atta Ullah Khan, Rutgers University - The State University of New Jersey (USA)
Prof. Dmitry Golberg, Queensland University of Technology (Australia)
Prof. Yoshio Bando, University of Wollongong (Australia)
Prof. Gunther Andersson, Flinders University (Australia)
Prof. Chunyi Zhi, City University of Hong Kong (China)
Prof. Xuebin Wang, Nanjing University (China)
Prof. Yanming Xue, Hebei University of Technology (China)
Prof. Gaulthier Rydzek, Université de Montpellier & CNRS (France)
Prof. Franck Gascoin, École Nationale Supérieure d'Ingénieurs de Caen & CNRS (France)
Prof. Sylvie Hebert, École Nationale Supérieure d'Ingénieurs de Caen & CNRS (France)
Prof. Florent Pawula, Université de Bordeaux (France)
Prof. Anthony Robinson, Trinity College Dublin (Ireland)
Prof. Tim Persoons, Trinity College Dublin (Ireland)
Prof. Rocco Lupoi, Trinity College Dublin (Ireland)
Prof. Seamus O'Shaughnessy, Trinity College Dublin (Ireland)
Prof. Jonathan Coleman, Trinity College Dublin (Ireland)
Prof. Michael Morris, Trinity College Dublin (Ireland)
Prof. Valeria Nicolosi, Trinity College Dublin (Ireland)
Prof. Roger West, Trinity College Dublin (Ireland)
Dr. Niall McEvoy, Trinity College Dublin (Ireland)
Dr. Aran Rafferty, Trinity College Dublin (Ireland)
Prof. Dario Narducci, University of Milano Bicocca (Italy)
Prof. Takao Mori, National Institute for Materials Science (Japan); University of Tsukuba (Japan)
Prof. Katsuhiko Ariga, National Institute for Materials Science (Japan); University of Tokyo (Japan)
Prof. Takashi Sekiguchi, National Institute for Materials Science (Japan); University of Tsukuba (Japan)
Dr. Mohamed B. Zakaria, National Institute for Materials Science (Japan); Waseda University (Japan)
Prof. Dayangku Noorfazidah Awang Shri, University of Malaysia Pahang (Malaysia)
Prof. Karina Vink, University of Twente (the Netherlands)
Prof. Agnieszka Witecka, Polish Academy of Sciences (Poland)
Prof. Dmitry V. Shtansky, National University of Science and Technology (Russia)
Prof. Andres Cantarero Saez, University of Valencia (Spain)
Dr. Andrés Seral-Ascaso, Instituto de Nanociencia y Materiales de Aragón (Spain)
Dr. Sang-Hoon Park, Korea Institute of Energy Research (South Korea)
Dr. John C.F. Zhang, EMPA- Swiss Federal Laboratories for Materials Science and Technology (Switzerland)
Prof. James Ryan, Swansea University (UK)
Dr. Atta Ullah Khan, Rutgers University - The State University of New Jersey (USA)
