Materials scientist Nguyen Duc Hoa: 'Nanomaterials are fascinating!'

As an applied physicist, have you ever been captivated by the romanticism and philosophy of theoretical physics? - The practicality and feasibility of theory are crucial because a theory can open up new perspectives on physical phenomena, leading to new technologies never before considered. Abstract concepts can lead to practical applications in nanotechnology, new materials, medicine, and quantum information… Therefore, the romanticism and philosophy of theoretical physics not only attract but also complement the practicality of applied physics, creating a fascinating journey of discovery and innovation. Combining theoretical and experimental physics provides a comprehensive and enriching experience for physicists. I have always been interested in and motivated by theoretical problems in physics. That is why our recent research has involved collaboration between experimentalists and theoretical and computational researchers. The theory promises a complete understanding of fundamental principles, as well as providing a comprehensive foundation from which new perspectives on physical phenomena can be opened.

Professor Dr. Nguyen Duc Hoa (left) with his inspiring mentor – Professor Dr. Nguyen Duc Chien

Professor, could you explain in simple terms one of your main research subjects: why do nanomaterials have so many unexpected properties? Nanomaterials operate at the atomic and molecular levels, where the usual physical laws applicable at larger sizes no longer apply, including size effects at the nanoscale, differences in surface-to-volume ratios, quantum effects, and strong interactions between atoms at the nanoscale. This creates novel physical, chemical, and biological properties, opening up vast potential applications. That's the appeal of nanomaterials in many fields, from medicine and electronics to energy… A striking example is the element gold (symbol Au): at larger sizes, it is yellow and insoluble in water; but when broken down to the nanoscale, it can be red, blue, or other colors depending on the particle size. Quantum dots are semiconductor nanoparticles with unique optical properties: when excited, they emit light whose color depends on the particle size. Quantum dots are used in TV displays (QLEDs), LEDs, and medical applications such as fluorescence imaging for disease diagnosis.

Together with my classmates from Hanoi Pedagogical University

What are 1D and 2D materials? Aren't all the materials we see 3D? - The world we perceive is a 3D spatial world. When one dimension is much larger than the other two dimensions, the object can be considered one-dimensional - that is, a 1D material; or when two dimensions are much larger than the other dimension, the object is almost considered two-dimensional - that is, 2D. At the nanoscale, 1D and 2D materials have many unique properties because their atomic structure is limited to one or two dimensions. A 1D material such as carbon nanotubes (hollow cylindrical tubes with a diameter <100 nanometers and a length that can reach a few micrometers or more) has extremely high partial tensile strength and good electrical and thermal conductivity. Nanowires (with a diameter < 100 nm and a very large length-to-diameter ratio, made from various materials such as metals, semiconductors, and metal oxides) can be applied in sensors or electronic components. A 2D material like graphene (with a thickness of one layer of carbon atoms arranged in a honeycomb lattice) possesses very strong mechanical properties, good electrical and thermal conductivity, and forms the basis for many research and applications in electronics, energy, and transparent electrodes. With nanotechnology, 1D and 2D materials are increasingly developing and having diverse applications, contributing to expanding human understanding of the physical world and promising groundbreaking technological advancements in the future.

Together with colleagues at ITIMS

Does the further we break down material particles, the more surprises and potential applications we discover? What remains if we break down particles to the absolute minimum? This is a fascinating question that helps clarify some fundamental principles in materials science and nanotechnology. Indeed, when we break down material particles to the nanoscale, many new and unexpected properties emerge. By further breaking down particles, we approach the most fundamental level of matter, namely atoms and subatomic particles such as protons, neutrons, quarks, leptons, and bosons – currently the smallest constituent units of materials. However, in the future, many more fundamental particles may be discovered or predicted to exist. This is what motivates materials scientists, because science has no end point. These are also the realms of romance, imagination, and philosophy in theoretical physics.

Since ancient times, nanoparticles have been found in many artifacts. What makes nanomaterials so important to modern society? Nanomaterials are incredibly important to modern society not only because of their small size, but primarily because of their unique properties and wide-ranging potential applications. Although nanoparticles have existed since ancient times (for example, the Lycurgus Cup will have different colors when viewed under reflected or transmitted light), our understanding and control of them have advanced dramatically in recent decades, opening up many new and groundbreaking applications in various fields. Thus, the ability to fabricate and control nanomaterials is the key. Nanotechnology not only opens up new potential for current applications but also creates breakthrough opportunities in the future, contributing positively to global economic and social development.

Together with ITIMS colleagues in Ba Vi

What about superconducting materials and their applications? Simply put, a superconducting material is a material that, when an electric current flows through it, will remain constant without degradation or energy loss. Superconducting materials have many different applications in fields such as medicine , power transmission, magnetic levitation trains, particle accelerators, etc. Currently, the most common device using superconducting materials is magnetic resonance imaging (MRI) machines, which use superconducting magnets to create the strong magnetic field necessary for detailed imaging of the inside of the body. Thanks to superconducting materials, MRI machines operate more efficiently and provide higher quality images. Recently, China successfully tested a magnetic levitation train with superconducting coils in a vacuum tube, achieving speeds of over 623 km/h (the design speed could reach 1,000 km/h). Perhaps the biggest challenge currently hindering the commercialization and widespread use of superconducting materials is their very low operating temperature. Superconductivity requires the use of complex and expensive cooling systems, such as liquid helium (-269°C) or liquid nitrogen (-196°C) to maintain low temperatures. Other challenges include high production costs, poor mechanical strength, complex fabrication technology, the ability to maintain superconductivity in strong magnetic fields, and the requirement for superconductivity under high pressure.

Discussing with colleagues in the laboratory.

What are the latest developments in Professor's research on nanomaterial applications? - After about 10 years of basic research, with certain achievements in the field of nanomaterials and sensors, our group decided to research integrated nanomaterials for application in IoT (Internet of Things) for breath analysis in disease diagnosis. This is truly a step forward and clearly demonstrates the interdisciplinary spirit in modern scientific research. The combination of nanomaterials, electronic components, and IoT not only opens up new potential for disease diagnosis but also contributes to the development of advanced medical technologies, or many applications in various fields such as industry, environment, security… Our idea originated in 2009 when we consulted a research paper published in Nature Nanotechnology by Hosam Haick (Israel) on the results of "Diagnosing lung cancer through breath using gold nanoparticles". This group's research indicates that by comparing the breath analysis results of healthy individuals and lung cancer patients, it is possible to identify lung cancer patients.

Interacting with experts at an event.

Our subsequent research has resulted in the creation of semiconductor gas sensors using nanomaterials that offer better responsiveness and lower gas concentration detection limits compared to gold nanoparticles, and are fully capable of being developed for applications in breath analysis for disease screening and diagnosis. This is a research direction applied in a project funded by the Vingroup Innovation Foundation (VinIF) in 2019. One of the driving forces behind our confidence in proposing this challenging project to the VinIF Foundation is the Foundation's "risk-taking" approach. Thanks to this progressive mechanism, instead of proposing a safe research direction with guaranteed product results, we decided to pursue a groundbreaking topic, even if it carried a high risk. The principle of this research is that when people suffer from certain diseases such as lung cancer, asthma, diabetes, etc., it affects the metabolic processes in the body, thereby creating characteristic gases (biomarkers) in the patient's breath at different concentrations. These biomarkers will change differently for each type of disease. Gas sensors are designed to identify and analyze these biomarkers, helping to detect diseases early without invasive methods such as biopsies. The wave of microchips and semiconductor chips is hotter than ever. According to the professor, in what direction should we take advantage of this wave? -That's right, this topic is very hot and is at the center of many research, development and application of modern technology. The growth and progress in this field not only promotes the development of information and communication technology but also has a profound impact on many other industries. But frankly, our semiconductor and microchip workforce is still too small, with limited expertise. Furthermore, Vietnam currently lacks a sufficiently strong semiconductor research center and a robust semiconductor ecosystem. In my opinion, Vietnam should capitalize on the semiconductor and microchip technology boom by focusing on niche areas with competitive potential, investing in R&D and human resource training, building a technology and supporting industrial ecosystem, and applying technology to key industries. These strategies will help Vietnam achieve sustainable development and compete effectively in the context of rapidly changing global technology. Thank you, Professor!

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Source: https://thanhnien.vn/nha-khoa-hoc-vat-lieu-nguyen-duc-hoa-vat-lieu-nano-day-thu-vi-185240531094042686.htm