Seminar on the topic: Advanced Materials, Photonics, and Applied Chemical-Biological Technology

At 2:00 PM on May 08, 2026, the IAST Institute will hold a seminar at the Meeting Room, 5th Floor, Library - Tan Hung Office with the following details:

1/ Assoc. Prof. Dr. Ngo Ngoc Ha will present on the topic: Photonic properties of Er-doped crystalline silicon
Abstract: During the last years, a remarkable research effort has been made to understand the physical properties of Si:Er material, as it is considered to be a promising approach towards improving the optical properties of crystalline Si. Impressive amount of experimental data and theoretical results have been gathered, and many fundamental questions pertaining to this system have been satisfactorily answered. Nevertheless, important problems remain. The most prominent of these are the thermal quenching of emission and the low optical activity of the Er dopants. These preclude the application of Si:Er for the development of practical devices. In this presentation, I will summarize the most important results of that research. Detailed description of the properties of Si/Si:Er multinanolayer structures, where preferential formation of a particular type of Er-related optical center has been realized. This in many aspects represents the most advanced form of Er-doped crystalline Si with prospects for applications in Si photonics, will be presented and discu ssed as a future research for Si:Er photonic applications

2/ Dr. Nguyen Van Quyet  will present on the topic: Electric field induced strain enhancement in BNKT lead-free electromechanical ceramics by co-doping with Li and Ta
Abstract: Electric field induced strain (EFIS) is one of the most important parameters for electromechanical actuators, with requiring precision displacement control or high generative force are widely used in applications, for which Pb(Zr,Ti)O3 (PZT) ceramics are currently widely used because of their excellent piezoelectric properties. However, the increasing demand for environmentally friendly materials in electronic and automotive industries promotes a wide range of studies on lead-free piezoelectric ceramics last decade. In this work, the effects of co-doping with Ta- and Li-ions on the microstructure, crystal structure, ferroelectric, and electric field-induced strain properties of Bi0.5(Na0.82K0.18)0.5TiO3 (BNKT) lead-free piezoelectric ceramics were investigated. Li substitution into Na-sites led to a ferroelectric-nonpolar phase transition and a large accompanying normalized strain (Smax/Emax) of 727 pm/V near the phase boundary, when 2.5 mol% Li and 2.5 mol% Ta were co-doped on A- and B-sites, respectively. The phase transition-related strain was thought to be induced by a decrease in the tolerance factor of the perovskite structure. We expect that this work could be helpful for further understanding the original enhancement in electrical field-induced strain in lead-free BNKT-based ceramics due to comparison between A- and B-site co-modifications

3/ Dr. Truong Ngoc Hung will present on the topic: Synthesis and biological activities of new 1,2,3-triazole derivatives of nucleosides
Abstract: A Click chemistry with CuSO4/hydrazine hydrate as the catalyst system for copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) of AZT and 5′-azido adenosine with terminal alkynes to give new 1,2,3-triazole derivatives. Screening for their anticancer, anti-inflammatory activities showed that some triazoles of AZT containing murayafoline A and indirubin scaffolds inhibited the growth of Hep-G2 and LU-1 with the IC50 values ranging from 11.01 to 19.87 μg/mL. Additionally, some triazole derivatives of adenosine indicated anti-inflammatory activity against RAW264.7 cells with the IC50 values within an interval of 12.00 – 59.48.00 μg/mL.

4/ Dr. Subramanian Ramanathan will present on the topic: Deciphering rhodamine B dye degradation via the non-radical (1O₂) pathway: Toxicological assessment using Zebra fish (Danio rerio) and yeast cells (Saccharomyces cerevisiae)

Abstract: This pioneering study revealed the potential of used face mask-derived carbon (UFMC) as a sustainable metal- free catalyst for peroxymonosulfate (PMS) activation, to effectively achieve the degradation of Rhodamine B (RhB) dye. Leveraging the surface oxygen functionalities of UFMC, the catalyst facilitated the generation of reactive oxygen species (ROS), predominantly singlet oxygen (1O2), which drives the efficient breakdown of the dye molecules. Although a slight decrease in catalytic performance was observed over cycles, with a minimum degradation efficiency of 58.8 % by the fifth cycle due to structural changes, the UFMC-catalyzed process demonstrated remarkable sustainability. Toxicological assessments using Zebrafish (Danio rerio) and yeast (Saccharomyces cerevisiae) indicated significant growth inhibition in response to untreated RhB, while water treated by UFMC showed no developmental deformities. This breakthrough underscored the potential of UFMC as an eco-friendly catalyst for wastewater treatment, offering a novel approach to environmental remediation. The findings of this study provided critical insights into the development of sustainable, metal-free catalytic systems for dye degradation, contributing to more environmentally conscious wastewater management practices.