Aristotle University of Thessaloniki (AUTH), Greece
Study of a new Anthracene-based polymer: From thin film characterization to fabrication of flexible yellow OLED devices
Mr. Kyparisis Papadopoulos holds a BSc in Physics and an MSc in Nanosciences& Nanotechnology from the Aristotle University of Thessaloniki. Currently, he is a Ph.D. candidate in Physics, also at the Aristotle University of Thessaloniki. He is specialized in Sheet-to-Sheet and Roll-to-Roll printing processes of organic electronics for techniques such as slot-die coating, screen printing, and spin coating. His work is focused on the field of Printed Organic Light-Emitting Diodes (OLEDs). Also, Mr. Papadopoulos participates in a national R&I project about developing a methodology and printing processes for large-scale OLED devices (project code: T1EDK-01039).
Great efforts in both academia and industry have been made toward the development of bendable lightings, such as light-emitting devices on substrates that can be flexed and stretched. Organic Light-Emitting Diodes (OLEDs) are the perfect candidates for such applications. Design and synthesis of advanced polymeric emitting materials with appropriate electrical and optical properties are necessary for the realization of stable-performance OLEDs. Especially, yellow emissions can be applied to signaling applications, vehicle electronics, wearable electronics, etc. In this study, we focused on the characterization of a lab-scale polymer bearing bis(styryl)-anthracene moiety in terms of film-forming ability, emission characteristics, and color purity. The optical and photophysical properties of the solution-processable thin films were thoroughly studied via NIR-Vis-far UV Spectroscopic Ellipsometry (SE) and Photoluminescence (PL) respectively, whereas the structural characteristics were examined by Atomic Force Microscopy (AFM). Subsequently, yellow light OLED devices are fabricated by spin coating technique and characterized in terms of their electroluminescence properties and electrical characteristics. Finally, promising preliminary results on flexible OLEDs, using a slot die coating processes, are reported.
Riga Technical University, Latvia
Morphology and Antibacterial Properties of ZnO-TiO2-SiO2 Sol-Gel Derived Coatings on Stainless Steel
Prof.Gundars Mezinskis is Dr.Sc.Eng. (1981) and Dr.HabilSc.Eng. (1998) in Faculty of Materials Science & Applied Chemistry of Riga Technical University (RTU). Leader of the Sol-Gel derived materials group of the Institute of Materials and Surface Engineering (RTU). He has authored over 110 publications (60 ISI publications among them) and author of 14 patents (2 EU patents among them). He led or participated in projects funded by national and European agencies as well as industrial companies. His research over the past 10 years has focused mainly on the development and study of coatings finding synthesis methods for material structure and material properties correlations.
Biofilms are formed in different environments, on virtually any surface with sufficient moisture and nutrients, as well as hospital equipment surfaces resulting in causing biological contamination. The specific negative effects of bacteria biological pollution thanks to the growth of various bacterial resistance to antibacterial drugs is becoming a growing problem in medicine. It is concluded that antimicrobial resistance (AMR) poses a major threat to human health around the world .
We report the influence of ZnO-SiO2-TiO2 sol-gel dip-coating (single and multilayer) deposited on mirror-polished stainless steel AISI 304 (SS) modified by a phosphate conversion coating. Different parameters such as particle size of sols used, coatings mechanical durability, wettability, topography, and morphology (AFM, SEM/EDS) were analyzed (Fig.1). The antibacterial effect was determined in samples with a novel dried droplet method  using E. coli ATCC 25922 and S. aureus ATCC 6538 strains.
Results obtained show that phosphate SS and then sol-gel coated materials show a higher antibacterial effect than polished materials respectively 73,0% vs 21,3% in case of S.aureus and 77,3% vs 44,3% in case of E.coli (Figure 1). PhosphatedSS materials showed an antibacterial effect of more than 99% against E. coli and more than 95% against S.aureus.
Aristotle University of Thessaloniki (AUTH), Greece
Photophysical and Electroluminescence characterization of blue emitting polymers for OLEDs
Tselekidou Despoinaholds has a BSc in Physics from the University of Ioannina and an MSc in Nanotechnology from the Aristotle University of Thessaloniki (AUTH). Currently, she is a Ph.D. student at the Nanotechnology Lab LTFN, at the AUTH. Her research interests involve the fabrication of thin films based on solution processes and the characterization through Spectroscopic Ellipsometry, Photoluminescence, Electroluminescence, and Atomic Force Microscopy. Specifically, her research activities focus on studying the properties of fluorescent and phosphorescent emitters for application in polymer OLEDs. In parallel, she holds 3 publications in international scientific journals, and she has participated in several international conferences.
Conjugated polymers have received increasing attention owing to their outstanding electrical and optical properties and for this reason, they are promising candidates to apply as an emissive layer in Organic light-emitting diodes (OLEDs). Recently, efficient, and stable blue-emitting materials have been one of the most important prerequisites to kick off the commercialization of OLEDs. Consequently, the development of novel, high-performance, and stable blue light-emitting materials with color purity is crucial. Specifically, the blue light-emitting materials remained a great challenge and triggered the research interest, in order to achieve stable and high-quality light. This is due to the intrinsic wide band gaps of blue emissive materials, which generate a high charge injection barrier and unbalanced injection and transportation of charges. In this study, we focus on the photophysical characterization of one novel, lab-scale blue emissive polymer based on Carbazole derivatives compared to the commercially supplied based on Polyfluorene derivatives. The comparative study of these materials helped to evaluate their properties, through the synergy of Spectroscopic Ellipsometry, Photoluminescence, and Atomic Force Microscopy techniques. Following, these blue-emitting polymers are used as an emissive layer in OLEDs. The electrical characteristics of fabricated OLED devices are investigated as well as the stability of the electroluminescence emission spectrum during the device operation. Finally, the determination of the optical properties in combination with the photo- and electro-emission characteristics provide us to evaluate the color stability of each material.
Fraunhofer Institute for Reliability and Microintegration, Germany
Prototype fabrication of sub-millimeter sized batteries based on silicon wafer technology batteries
Robert Hahn received his Master's and Ph.D. degrees in electrical engineering from the Technische Universität Dresden. He is head of the micro energy storage group of Fraunhofer IZM. He works for more than 20 years in the field of batteries and microelectronic packaging. He has taken over the coordination of several national and European research projects for the development of new batteries and integrated power supplies for microsystems, energy autarkic, and medical electronics. He is head of the Fraunhofer micro battery initiative MicroLIB. Dr. Hahn has filed 30 patents in the area of micro-energy systems and authored and co-authored more than 100 journal and conference publications as well as book chapters. He was the coordinator of the FP7 project MATFLEXEND for the development of Lithium-ion batteries based on nanofibers. Since 2018 he is in charge of the micro battery prototyping line at Fraunhofer IZM that is used for the fabrication of micro-batteries for industrial customers.
Several emerging innovations in fields like the internet of things, medical/health, nano-robotics, and the military require extremely miniaturized batteries and special form factors. A technology was developed that combines advanced silicon wafer-level packaging and micro-print and deposition processes to fabricate thousands of small batteries in parallel on a substrate. While standard lithium-ion electrode materials are used adaptions were made for the electrolyte to reduce the vapor pressure. A key technology is the wafer fabrication on glass carriers because the silicon walls of the battery housing are very thin. Deep reactive ion etching is used to fabricate the battery housing, as well as PECVD oxide/nitride deposition to isolate the active battery materials from the silicon walls. Special focus is on the low-temperature hermetic sealing of the batteries on wafer-level since battery degradation and increase of internal resistance start at temperatures above 90 °C. A combined process of polymer bonding of the battery lid and additional metallization was developed to achieve both: an assembly and packaging technology that can be performed simultaneously on thousands of micro-batteries on the substrate and a robust and tight encapsulation.
The attainable energy density as a function of active materials and battery size will be shown. At battery dimensions between 1x1 … 10x10 mm2 and thickness between 200 μm and 1 mm the overall energy density is ca. 300 Wh/l. All available electrodes for lithium-ion batteries like graphite and lithium titanate anodes and NCA; NCM and LFP cathodes were qualified for the micro battery fabrication. With help of various electrode combinations, cell voltages between 1.5 and 4.0 Volts can be realized. Carbon nanotubes are used to increase electrical conductivity and reduce the contact resistance between electrodes and current collectors. Finally, a process yield of the battery fabrication process will be discussed.
University of Belgrade, Serbia
Ferro electric properties of BiFeO3 ceramics with cation substitutions at Bi-site (La3+, Eu3+) and Fe-site (Nb5+, Zr4+)
Dr. Aleksandar Radojkovic is a senior research fellow at the Institute for Multidisciplinary Research, University of Belgrade. he as worked Senior Research Fellow at, Institute for Multidisciplinary Research in 2022. Research Fellow, Institute for Multidisciplinary Research in 2014. Research Assistant, Institute for Multidisciplinary Research in 2010.His Education Ph.D. in Materials science, Faculty of Technology and Metallurgy, University of Belgrade, Dissertation title: “Properties of yttria doped barium cerium oxide ceramics as an electrolyte for solid oxide fuel cells”.in 2014He Studied BSc in Norwegian language and Scandinavian literature, Faculty of Philology, the University of Belgrade in 2004He studied MSc in Inorganic Chemical Engineering, Faculty of Technology and Metallurgy, the University of Belgrade in 2003His research interest is Proton conductivity and electrical properties of BaCeO3-based materials and their application in solid oxide fuel cells; Synthesis and characterization of multiferroic BiFeO3, using doping and codoping as a strategy for tailoring its ferroelectric and magnetic properties; Development of hybrid composites based on biopolymers and metal oxides as environmentally safe pesticides.
BiFeO3 is one of few multiferroic perovskites that exhibits both magnetic and ferroelectric properties at room temperature. However, it is also distinguished by high leakage current, low remnant electric and magnetic polarization, and high electric coercive field. These features keep it away from any practical use in electronics. Therefore, many attempts have been done to improve the properties of BiFeO3 by Bi- or Fe-site doping or by both. Previous investigations suggest that doping with Nbat Fe-site can positively affect the magnetic behavior of BiFeO3 and decrease the leakage current.
In this study, a variety of cation substitutions at Bi-site (La3+, Eu3+) and Fe-site (Nb5+, Zr4+) were examined with the aim to investigate their possible synergism and benefit for the ferroelectric properties. The role of the cations with higher valence is to suppress the formation of structural defects during syntheses, such as oxygen and bismuth vacancies. These defects are responsible for high leakage currents, and consequently, low breakdown voltages characteristic of the pure BiFeO3. On the other hand, rare-earth cations at the Bi-site usually enable densification of the ceramics in a wider range of temperatures, preventing bismuth loss and formation of defects and secondary phases during sintering. However, do pant concentrations above 10–15mol% may give rise to transition from polar, rhombohedral (R3c) to non-polar, orthorhombic (Pnma) symmetry.
The carefully selected compositions of doped BiFeO3 were synthesized by a simple hydro-evaporation method. The ceramics samples were characterized using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and polarization techniques, including leakage current measurements. Although it was shown that the introduction of Nb5+or Zr4+decreased the leakage current, they surprisingly deteriorated the ferroelectric properties even at concentrations as low as 1 mol%. This effect was more pronounced for the samples containing Nb. On the contrary, both La3+ and Eu3+(incorporated at the Bi-site) improved the ferroelectric properties as their concentrations increased, whereby the La-doped samples exhibited higher remnant electric polarization at observed electric fields. The highest remnant electric polarization of31.9 µC/cm2at 150 kV/cm, was measured for Bi0.85La0.15Fe0.998Zr0.002O3, indicating the synergetic effect of La3+ and Zr4+, which is limited to very low Zr4+concentrations.
Vajresh Kumar N
Indian Institute of Science, India
Functionalization of Fiber Bragg Grating Using Different Coating Methods
Optical fiber gratings have gone through an improved growth of development in the current years in track with the observation of narrow-band reflection in the photosensitive core region of silica optical fiber which is Germanium or boron-doped. Fiber Bragg grating is a periodic modulation of the refractive index along with the core of a photosensitive fiber. The refractive index changes are made by exposing the fiber to the interference pattern of Ultraviolet light. FBGs are less sensitive to refractive index (RI) variations of the external medium as the fiber is covered by cladding, limiting the application of FBGs being used in biological and chemical sensing applications. The surface of the e-FBG is modified with functionalized coatings based on the target to detect the change in RI using different coating techniques and different nanomaterials such as AgNP, AuNP, etc., and is characterized. This sensing probe can be used in different biological sensing applications.
Keywords: Fiber Bragg grating, coating techniques, nanoparticles, functionalization,
Tarbiat Modares University, Iran
Oocyte Characterization Using Microfluidic Channel
Dr. Davood Fathi received a B.Sc. degree in the field of electronic engineering from Amirkabir University of Technology, Tehran, Iran, in 1990, and an M.Sc. degree in the field of biomedical engineering from Sharif University of Technology, Tehran, Iran, in 1994. After a couple of years working in the industry, he worked toward a Ph.D. degree between 2006-2009 in the field of nanotechnology with the Nanoelectronic Center of Excellence, Thin Film and Photonics Research Laboratory, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran.
Dr. Fathi has joined in 2010 as a member of the faculty of the Department of Electrical and Computer Engineering, Tarbiat Modares University (TMU), Tehran, Iran.
He has been the reviewer for more than 20 international journals including IEEE, OSA, Elsevier, Springer, John Wiley, and so on.
His current research interests include Nanoelectronics; Nanotechnology; Nanophotonics and Optoelectronics; Nano-biotechnology; Nano-microfluidics; Biosensors; Solar Energy.
He is also the author or co-author of more than 85 scientific journal and conference papers in various fields of Nanoelectronics, Nanotechnology, and Photonics.
Dr. Fathi is currently an Associate Professor in his department.
He has supervised more than 40 M.Sc. students and 5 Ph.D. students. One Ph.D. student and 3 M.Sc. students are currently working on an interdisciplinary topic of oocyte evaluation based on the design and fabrication of nano-micro fluidic systems.
He has been selected as an invited or keynotes speaker for several international conferences such as CCET-2022, CCT-2022, Nanotechnology 2022, Microfluidics 2022, Material Chemistry 2022, and so on.
Oocyte development is largely dependent on its mechanical properties. Cell mechanics control the outcome of cell division. In recent years, various techniques such as micropipette aspiration (MPA) and optical tweezers are being used to measure the mechanical properties of membranes. The traditional MPA systems, however, have low throughputs and limited potential for automation and require bulky infrastructures. These methods have been used to investigate the mechanical characteristics of single cells including the elastic and viscoelastic properties, etc. In MPA methods, by applying a specific suction pressure, the cell aspirates into a micropipette. The amount of aspirated surface into the pipette is then recorded and measured using an electron microscope over time. During the aspiration, any leakage between the cell and the micropipette needle causes an error in the measurement of suction pressure. Due to the complexity of pressure measurement, the accuracy of the results largely depends on the skill of the user of the equipment. Furthermore, surface water evaporation and bubbles in the micropipette lead to errors in measuring the applied pressure. Although the aspiration force is applied to the entire oocyte volume, since the direction of the applied pressure is random, the average values for the measured mechanical characteristics of the entire cell are considered. On the other hand, these techniques are generally labor-intensive and time-consuming, typically involving a difficult process of manipulation.
Microfluidic channels have been developed in the past two decades for various biomedical applications, due to advantages such as real-time analysis, system integration, transparency for direct optical access, labor, precise control, lower cost, and reduced space. Furthermore, microfluidic channels can be integrated with other techniques and can enhance traditional cell analysis methods. Biological cell analysis and characterization can be performed based on the shape, size, and deformability of single cells in microfluidic chips. Various methods have been applied for microfluidic single-cell trapping including hydrodynamic trapping, dielectrophoresis trapping, chemical trapping, gel trapping, magnetic trapping, acoustic trapping, laser trapping, etc.
In this lecture, I present a new method for designing and manufacturing microfluidic channels in order to measure and evaluate the mechanical properties of mouse oocytes. The proposed process has the advantages of high accuracy and fast and easy operation. In our proposed technique, the oocytes are trapped in a specific channel, as shown in Fig. 1.
Although the designed and manufactured structure has microfluidic dimensions, in the design and analysis of the structure, knowledge and software environment in the field of nanotechnology and nanoelectronics have been used.
Indian Institute of Science, India
Immobilized functionalized silver nanoparticles to detect Chromium in water.
A simple yet effective way to detect chromium, one of the major water contaminants by using Tartaric acid-functionalized silver nanoparticles immobilized on the surface of etched Fiber – Bragg grating sensors (e-FBG). The target analyte and functionalized nanoparticle could be further confirmed by performing UV-Visible spectroscopic analysis while the structure of the coating surface could be analyzed by SEM imaging.figure1 provides an insight into the working principle of the developed sensor. The limit of detection(LOD) falls well within the permissible range. The sensitivity and linearity of the sensor show promising signs of developing into a field-deployable unit.
Keywords: Chromium detection, silver naoparticle,functionalization, e-FBG.
Paula Fonseca Antunes Vieira
Paraíba University, Brazil
Analysis of the diagnostic potential of nano sensors in Breast Cancer 3D tumor
Paula Vieira is a Bachelor of Biomedical Sciences (2020) from Vale do Paraíba University. She began her MSc studies in Biomedical Engineering at the Nanosensors lab in 2021. with a scholarship from Coordination for the Improvement of Higher Education Personnel, CAPES [grant number: 88887.649530/2021-00]. She has experience with the synthesis and functionalization of nanoprobes, photodynamic therapy, 2D and 3D cell culture, xenografts, photosensitizers, and nanocomposites. Her research interests include nanotechnology, 2D and 3D cell culture, nanoprobes, photodynamic therapy, and non-conventional diagnosis/treatment methods.
Overexpression of the Epidermal Growth Factor Receptor (EGFR) has been associated with malignancies with a worse prognosis, and the EGF protein activates its signaling pathways, which regulate cellular functions. As a result, the EGFR receptor is being investigated for a wide range of tumor diagnostics, encouraging the development of novel methods to improve quality and efficiency. Nanomaterials can recognize cancer cells by targeting certain biochemical pathways, highlighting nanomedicine's potential. Three-dimensional (3D) cell culture has arisen as an alternative to in vivo experiments for the formation of a heterogeneous microenvironment and the representativeness of the cellular mechanisms present in malignancies. Cell-cell and cell-extracellular matrix interaction is enhanced in 3D cell culture, preserving tissue shape and structure. In this regard, among the several types of 3D environment development that are conceivable, micro molded agarose allows large-scale reproducibility. In this study, breast cancer spheroids were created on micro molded agarose by the MDA-MB-468 strain. By functionalizing the EGF protein and Chlorine e6 (Ce6) in gold nanoparticles, the nanosensors were synthesized and applied to the spheroids for the detection of EGFR. Iron Oxide Nanoparticles Stabilized by Sodium Citrate. In: Second International Conference of Nanoscience and Nanobiotechnology, 2021, Brazil. In Vitro Matt Assay of Magnetic Nanoparticles Negatively Charged by Surfactant. In: Second International Conference of Nanoscience and EGF protein is delivered to the EGFR receptor through active targeting, and Ce6 serves as a fluorescent flag molecule. The tumors were cultivated for 21 days after being cast in 2% agarose molds. Flow cytometry was used to detect the presence of fluorescence and the cell death pathways after the nanosensors were applied. Annexin V (AnnV) and propidium iodide (PI) staining were used to assess cell death pathways in viable (AnnV- PI-), apoptotic (AnnV+ PI-), and necrotic (AnnV+ PI+) cells. The characterization of this tissue reveals the presence of fluorescence and the absence of substantial apoptosis and necrosis deaths.
Marcela Aparecida Cândido
Vale do Paraíba University, Brazil
Theranostic characterization of breast cancer treated with Nanoprobes, and Thermal Ablation Therapy
Marcela Cândido received a chemical engineering degree from Vale do Paraiba University in 2018. She has been a Ph.D. student at Nanosensors Laboratory (IP&D/UNIVAP), with a scholarship from São Paulo Research Foundation, FAPESP [grant number 2019/26353-3]. Her expertise in the field of nanoparticle synthesis and functionalization, molecule modification as well as the photodynamic and photothermic therapies in cell cultures.
Cancer is a problem for public health and new types of therapies have been studied. Among them, Photothermal Therapy (PTT), has been investigated in recent years, primarily as a non-invasive cancer treatment with fewer side effects for patients. The heat energy is produced when iron or gold nanoparticles are irradiated in the near-infrared range (700-1000 nm), which is capable to start the death process for a specific cell because tumor cells have a lower heat tolerance than normal ones. SPIONs@Au are multifunctional core-shell nanoparticles with an iron core that improve the material's chemical, physical, and optical capabilities. In this context, we investigated the synthesis and characterization of Au@SPIONs, as well as the surface functionalization with EGF-α-lipoic acid (increasing specificity for cells with EGFR overexpression) and chlorin e6 (Ce6)-cysteamine complexes, composing a theranostic nanoprobe (TP). The Confocal Fluorescence Microscopy evaluated TP internalization in the triple-negative breast cancer (TNC) cell line, which has a poor prognosis. Also, PTT was performed associated with Au@SPIONs and TP. The effectiveness of the technique was determined by flow cytometry, labeling viable cells, apoptotic cells, and necrotic cells. The results, SPIONs@Au showed a color change to red, and the presence of an absorption band centered at 530 nm. The Ce6-cysteamine complex was formed efficiently, having a resonant band at 670 nm, allowing the diagnosis in biological samples via fluorescence. Internalization of the TP in the cell cytoplasm was confirmed, indicating that it might be used as a diagnostic marker. The PPT in TNC produced positive outcomes, with an apoptosis death preponderance. Aside from that, the functionalized ce6 complex permits Photodynamic Therapy to be used, broadening the variety of uses.
Ahmed Raza Khan
Australian National University, Australia
Monitoring Folds Localization in ultra-thin Transition Metal Dichalcogenides using Optical Harmonic Generation
Ahmed Raza Khan did his Ph.D. at Australian National University. He is working as a post doctoral researcher in the School of Engineering, Australian National University. His research interests include linear and nonlinear optics, strain-engineering of nano-materials, and non-conventional machining processes. He has published many papers, including in high-impact journals like ACS Nano, Science Advances, Materials today, and Nano Letters, etc.
Folding is an effective technique to alter the optoelectronic properties of two-dimensional (2D) materials such as interlayer coupling, band gap, etc. Optical techniques such as PL and Raman were used in the past to probe the folds localization. Here, we show that optical second harmonic generation (SHG), which is sensitive to the crystalline symmetry of 2D materials, is a powerful probe to monitor the fold localization in TMDCs. Two-dimensional 2H Transition Metal Dichalcogenides (TMDC) are particularly well-suited for the study because their SHG investigation has already been done, in addition, they can be easily folded due to their high flexibility. Our study includes the fabrication of clean folds on ultra-thin layers of TMDCs, optical characterization of the folds using SHG imaging, and theoretical calculations to prove our findings. We find that SHG from the folds is a coherent superposition of the SHG from the individual layers of the fold, with a very small phase difference depending on the folding angle. The SHG response is theoretically calculated as a function of the folding angle. Our results establish SHG as an effective tool to monitor fold localization in 2D TMDCs.
Sharif University of Technology, Iran
The investigation of photocatalytic properties ofNi0.8CO0.2/Zn0.4Cd0.6S/g-C3N4as a nano-photocatalystfor pollutants, degradation, andH2 generationbywater splitting
Fatemeh Sousani joined the department of material science and engineering of the Shariff University of Technology as a doctoral candidate in September 2020. Her doctoral thesis is entitled “the performance improvement of H2 production via water splitting with NixCo1-x/ZnxCd1−xS/g-C3N4 nano hybrid photocatalysts” under the supervision of Prof.SayedKhatiboleslam Sadrnezhaad and Dr. Parvin Abachi. She received her master’s degree in 2017. She worked on the design of the germanium–carbon antireflection coatings. She had also a research project to investigate the thermal stability properties of germanium-carbon coatings. The results of her master’s thesis were published in reputable ISI journals.
Graphitic carbon nitride (g-C3N4) is a promising metal-free visible-light photocatalyst due to its strong visible light response, high thermal and chemical stability, and available low-cost raw materials. This substance has gained significant attention for the degradation of pollutants and photocatalytic water splitting for H2 production under visible light. Nevertheless, due to the relatively large band-gap, low charge-carrier mobility, and thus limited effective use of sunlight, the photocatalytic hydrogen evolution efficiency of pristine g-C3N4is still unfavorable. Several strategies, such as morphological control of g-C3N4, creating heterojunctions with semiconductors, and doping with other elements have improved its photocatalytic efficiency. This study's aim is to improve the photocatalytic performance of g-C3N4for degradation of pollutants and hydrogen evolution by creating Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4 nano-photocatalyst that makes it more effective under visible-light irradiation. Here, Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4nano-photocatalyst is produced via a facile hydrothermal and chemical reduction method. Then, the morphology, structural, optical, and photocatalytic properties of the nanohybrid were characterized by field emission scanning electron microscope (FE-SEM), X? ray diffraction (XRD), Brunauer–Emmett–Teller (BET), UV? vis diffuse reflectance absorption spectra (DRS) and photoluminescence (PL). With the formation of Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4, the bandgap energy of the g-C3N4 decreases from 3.01 to 2.77 eV, and the absorption edge increases from 412 to 448 nm. The Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4absorption edge is located between g-C3N4 and Zn0.4Cd0.6S and has a stronger visible light absorption compared to g-C3N4 and Ni0.8Co0.2/Zn0.4Cd0.6S in the range of 410 to 620 nm. The performance of the Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4nano-photocatalyst in the removal of methylene blue (MB)from an aqueous solution can be used as a basis for its proper performance for water splitting and H2 production too. Photocatalytic degradation of methylene blue in an aqueous solution was carried out under an LED lamp (100 W, 400-700 nm) illumination for 120 min. It was found that the degradation efficiency of methylene blue was 96% within this period. Thus, the Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4nano-photocatalyst can act as a potential photocatalytic material for the degradation of pollutants and production of hydrogen under visible light.
University of Szczecin, Poland
Metabolic Insertion of Titanium Into the 3D Structure of Diatomaceous Biosilica
M.Sc. Weronika Brzozowska obtained MA degrees in Quantum Chemistry and Forensic Chemistry at the Faculty of Chemistry at the Nicolaus Copernicus University in Torun in 2016 and 2019. During her second master's thesis research, she implemented the Ministry of National Defense project entitled "Study of the physicochemical properties of intelligent composites with the use of electroactive materials" in cooperation with the Polish Naval Academy based in Gdynia. Currently, she works on modifying algae - diatoms -with metal ions to obtain innovative nano-silica materials with unique optoelectronic properties and semiconductors. These activities are directly related to the doctoral studies that she carries out as part of the Doctoral School of the University of Szczecin (US), in the discipline of Earth and Environmental Sciences. She is also a member of the US research team implementing the project "Advanced biocomposites for the economy of tomorrow BIO-GNET".
In the development of modern technologies, microorganisms, particularly unicellular algae (microalgae), are the growing inspiration due to their abundance and unique properties . Microalgae have the capacity to synthesize phenomenal mineral composites under natural conditions (calcium carbonate, silica) with complex hierarchic structures. The intricately ornamented silica shells known as frustules are a unique feature of diatom cells. The siliceous walls of frustules are perforated by periodic arrays of pores with diameters ranging from nano- to microscale forming openwork three-dimensional (3D) silica structures. Obtaining such structures of inorganic materials is one of the main challenges in the new materials and devices development. According to published works, the diatomaceous biosilica characterized by perfectly ordered3-D structure, thermal and mechanical stability, unique optical properties, and biocompatibility can be a valuable resource for applications in modern technologies for the production of optoelectronic devices, biosensors, gas sensors, catalysts, adsorbents, efficient filters, semiconductors, solar cells, templates for nanolithography, drug carriers or building material in the synthesis of bone implants [4,5].
The main aim of this study was to evaluate the ability of the diatom species Pseudostaurosiratrainorii to metabolically insert soluble titanium from a culture medium into the structure of their amorphous silica cell walls, by the cultivation of selected diatom species under laboratory conditions. The culture of diatom species was cultivated using Erlenmeyer flasks (3000 ml) with Guillard’sF/2 growth medium with soluble titanium concentrations range by2.5 mg/l to 90 mg/l and soluble silicon concertations ranging from 1.2 mg/l to 500 mg/l.
The morphological and structural features, elemental composition, structure, photoluminescence properties, and thermal stability of the obtained biosilica were examined using a set of techniques comprising scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy, IR spectroscopy, X-ray powder diffraction, and thermogravimetry. The figure shows some of the absorbing and compelling results obtained during the doping of diatomaceous silica with titanium ions.