Ramzi Maalej

University of Sfax | US · Department of Physics

Peralkaline Sm3+-doped aluminosilicate glasses with different network modifier ions (Mg2+, Ca2+, Sr2+, Ba2+, Zn2+) were investigated to clarify the effect of glass composition and glass structure on the optical properties of the doped Sm3+ ions. For this purpose, the Sm3+ luminescence emission spectra were correlated with the molecular structure of...

In this paper, the determination of Thiram fungicide by a novel modified screen-printed carbon electrode (SPCE) fabricated modifying the working electrode (WE) with 2D-GO/WS2 nanohybrid composites, is reported. Scanning electron microscopy (SEM), Raman spectroscopy, and fluorescence analysis (PL) were used to reveal the morphological and microstruc...

A simple and sensitive electrochemical sensor was developed for the detection of folic acid (FA) based on gold nanoparticles (AuNPs) dispersed on exfoliated MoS2 (2D-MoS2) nanosheets by a simple impregnation method. The prepared 2D-MoS2 and AuNPs-MoS2 samples were characterized by scanning electron microscopy (SEM-EDX), UV-Vis, and Raman spectrosco...

In the optical energy gap, visible and near-IR emission of halide phosphate glasses with a composition of 40P2O5-30ZnO-20LiCl-10BaF2 in mol% doped with 3.5 × 104 ppm Pr2O3, referred to as PZLBPr, were synthesized. The UV-VIS-NIR and spectroscopic properties of these glasses were also predicted. The current glasses had broadband emission photolumine...

Undoped Y2Sn2O7 and Eu3+ doped Y2Sn2O7 samples with doping concentrations 7%, 8%, 9%, and 10% are successfully synthesized by the co-precipitation method. A complete structural, morphological, and spectroscopic characterization is carried out. XRD measurements reveal that samples crystallize in the pure single pyrochlore phase and Eu3+ ions occupy...

Surface plasmon resonance sensors (SPR) using copper for sensitive parts are a competitive alternative to gold and silver. Copper oxide is a semiconductor and has a non-toxic nature. The unavoidable presence of copper oxide may be of interest as it is non-toxic, but it modifies the condition of resonance and the performance of the sensor. Therefore...

Descriptors derived from atomic structure and quantum chemical calculations for small molecules representing polymer repeat elements were evaluated for machine learning models to predict the Hildebrand solubility parameters of the corresponding polymers. Since reliable cohesive energy density data and solubility parameters for polymers are difficul...

Program of Nano Boston Conference 2021. I am the chairman of the third day and give a talk on latest results.

Certificate of participation in the summer bootcamp organized by African MRS https://ramzimaalej.wixsite.com/pam-group/achievments

Understanding the atomic structure of glasses is critical for developing new generations of materials with important technical applications. In particular, the local environment of rare-earth ions and their distribution and clustering is of great relevance for applications of rare earth-containing glasses in photonic devices. In this work, the stru...

The choice of substrate is crucial for device applications, in particular for atomically thin materials such as monolayer transition metal dichalcogenides. The interaction between the active material and the substrate could be exploited to improve the device performance. In this work, we used a Sm-doped aluminosilicate glass (Sm-ASG) as a substrate...

A series of green emitting Gd2O3:Tb3+ (Tb: 0-10% mol) nanoparticles (NP) were synthesized using the hydrothermal method, then characterized and evaluated for latent fingerprint visualization. X-ray diffraction study (XRD) revealed a cubic structure of the nanoparticles and the total incorporation of the terbium in the Gd2O3 matrix. Field Emission-S...

Invited Speaker and session chairman at NANO Boston international Conference 7-9 December 2020

Y 2 O 3 rare earth Nanoparticles Suspension Hamaker 2 program. a b s t r a c t Sol-gel processing was used to fabricate undoped and rare-earth (Er, Yb) doped very fine Y 2 O 3 nanoparticles under supercritical drying conditions of ethanol using an autoclave and annealed at 500 • C and 800 • C for 2 h. The Er and/or Yb concentration is fixed at 5 mo...

Two-dimensional (2D) layered Transition Metal Dichalcogenides (2DMX2) are materials with unique optoelectronic properties, high surface to volume ratio and the high carrier mobility. The combination of noble metal nanoparticles (MNPs) with 2DMX2 opens new avenues in conceiving more efficient plasmonic sensors, allowing one to optimize both the elec...

Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) were prepared by liquid-phase exfoliation and used to modify screen-printed carbon electrodes (SPCE), in order to develop an electrochemical sensor for the simultaneous determination of dopamine (DA) and tyrosine (Tyr) in presence of uric acid (UA). To demonstrated the layered morphology, t...

Fitting optical properties of metals is of great interest for numerical methods in electromagnetism, especially finite difference time domain (FDTD). However, this is a tedious task given that theoretical models used usually fail to interlink perfectly with the experimental data. However, in this paper, we propose a method for fitting the relative...

Er³⁺ doped, Yb³⁺ doped, and Er³⁺/Yb³⁺ co-doped Y2Ti2O7 phosphors with various concentrations of Er³⁺ (12–20%), Yb³⁺ (1-10 at%), and Er³⁺Yb³⁺ (1%, and 1,2,3%, respectively) were prepared by solid-state reaction. The phase structure and purity of all prepared phosphors were studied by X-ray diffraction analysis followed by measurement of the hydrodyn...

We demonstrate a simple enzyme-free electrochemical sensor for tyrosine (Tyr) detection, based on the enhanced catalytical activity of two-dimensional molybdenum disulphide nanosheets (2D-MoS2), prepared by liquid phase exfoliation and deposited on commercial screen-printed carbon and gold electrodes (SPE). We first evaluate the electrochemical per...

Associate Editor at IEEE Transactions on Nanobioscience Journal https://www.embs.org/tnb/associate-editors/

We are delighted to invite you to the Fourth International Conference on Engineering Sciences in Biology and Medicine (ESBM'2019) that will take place from 29 to 31 of October 2019 in Sfax, Tunisia. https://ramzimaalej.wixsite.com/pam-group/esbm2019

En vue de l'obtention du DOCTORAT Dans la discipline : Physique Par Ikram BENAMMAR Synthèse par voie sol-gel et mise en suspension des nanoparticules dopées (Er, Yb) en vue d'application photovoltaïque Soutenue le 15 juillet 2019, devant le jury composé de : Synthèse par voie sol-gel et mise en suspension des nanoparticules dopées (Er, Yb) en vue d...

République Tunisienne Ministère de l'Enseignement Supérieur et de la Recherche Scientifique Université de Sfax, Faculté des Sciences de Sfax Avis public de recrutement d’un post-doctorant dans le cadre du projet de recherche PAQ COLLABORA « KIDAEM » Article 1 : Objet de l'annonce La Faculté des Sciences de Sfax (FST), sise à Route de Soukra km4,...

Certificate of Particpation in the NAUSS conference 2018

Development of new biosensor based on MoS2 nanosheets.

In this work, rare earths (Erbium and Ytterbium) doped or co-doped yttrium oxide (Y2O3) nanopowders has been successfully prepared by hydrothermal-assisted sol-gel method using supercritical drying of ethyl alcohol and annealing at 500°C and at 800°C for 2 h. Nanopowders were prepared with various composition: Y2O3 pure, 5 mol.% Er : Y2O3, 5 mol.%...

The medium-range atomic structure of magnesium and barium aluminosilicate glasses doped with Gd2O3 as a model rare earth oxide is elucidated using molecular dynamics simulations. Our structure models rationalize the strong dependence of the luminescence properties of the glasses on their chemical composition. The simulation procedure used samples'...

A series of phosphate glasses including two compositions that are similar to commercial laser glasses and 3 new compositions doped with 2 × 1020 Er3+/cm3 were prepared by using the classical melt quenching technique. The new glass compositions show much better glass forming properties than the commercially available glasses, lower molecular weights...

Two series of mixed barium magnesium alumino silicate glasses with the molar compositions (35-x) BaO · x MgO · 10 Al2O3 · 55 SiO2 (mol%) (peralkaline series: x=0, 2.5, 5, 7.5, 10, 15, 25, 35) and (20-x) BaO · x MgO · 20 Al2O3 · 60 SiO2 (mol%) (metaluminous series: x=0, 10, 20) have been prepared and doped with Tb³⁺ ions with a constant concentratio...

High dense tellurite glass with system 80TeO2–5Bi2O3–15WO3–doped with (0, 2000, 10000 ppm Er2O3) (labeled TBW, TBW: 1000 ppm Er2O3 and TBW: 20000 ppm Er2O3) were prepared. Physical parameters such as density (), glass transition temperature (Tg), thermal stability (T), optical energy gap and refractive index (n), of prepared glasses were evaluated....

This certificate was delivered as recognition of efforts as editor of the special issue (december 2017) of the IEEE Transactions on Nanobiosciences (IF 2.7)

I am proud to receive my certificate of appointment as Associate Editor of the IEEE transactions on Nanobiosciences Journal

The glasses with composition 50P2O5-30ZnO-20SrO (PZS) in mol% doped with 30,000ppm Er2O3 and 50P2O5-30ZnO-20CdO (PZC) in mol% doped with 30,000ppm Er2O3 were prepared by quenching -melting method. Spectroscopic and Judd-Ofelt (J-O) parameters, Ωt, of these glasses were evaluated. Moreover, different radiative properties and optical energy gap of pr...

Tellurite glass with composition 90TeO2-10Nb2O5-10ZnO in mol% codoped with x(Tm2O3/Dy2O3), where x = 10,000, 20,000 and 30,000 ppm were prepared by quenching melting technique. The optical density and photoluminescence properties of this glass were studied. Spectroscopic parameters such as the absorption cross section, σab(λ), emission cross sectio...

Engineering Sciences for Biology and Medicine (ESBM) is an exciting platform for researchers to discuss a wide range of modern biology and medicine goals. The third edition ESBM 2017 conference was organized by the Tunisian Association of Academic Researchers ATCU, in collaboration with the Technopark of Sfax and the Digital Research Centre of Sfax...

1 Workshop in the frame of the bilateral TUNGER project.

We proposed a new approach to determination of Judd-Ofelt intensity parameters of Er³⁺ doped phosphors via their absorption spectra. To validate this approach, JO parameters of Er³⁺ doped BaGd2ZnO5/PMMA and NaYF4/PMMA composites were calculated and in a good agreement with the other glass and crystal. The spontaneous radiative transition probabilit...

The luminescence characteristics of GaN films implanted with Er at low doses were evaluated. The defect-related yellow luminescence (YL) and green luminescence (GL) bands observed under direct excitation with 488 nm were attributed to the transitions via different charge levels of the same defect. The quenching behavior of the luminescence intensit...

This paper reports on the spectral results of Nd3+/Yb3+ ions codoped 50P2O5-30ZnO-20SrO (PZS ,in mol%) glasses which were prepared by a melting technique. The glass transition temperature and spectroscopic properties of these glasses were estimated. From the absorption spectra, Judd-Ofelt (J- -O) intensity parameters, several radiative properties s...

In contrast to Yb3+ which is a well-investigated optically active ion, the spectroscopic properties of its divalent counterpart Yb2+ in glasses are hardly investigated, although Yb2+ might have a notable influence on the luminescence properties of Yb3+-doped glasses even at low Yb2+ concentrations because of its strong f-d transitions. In this pape...

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Keywords: TiO2, rare earth, nanoparticles, sol-gel, supercritical drying. Abstract New titanium dioxide preparation protocols doped with rare earths composition of TiO2, Er (5%): TiO2, Yb (5%): TiO2, Yb-Er (5-5%): TiO2 and Yb- Er (10-5%):TiO2 nanoparticles doped rare earths are prepared by sol gel with a supercritical drying of ethanol. In this con...

Lanthanide doped inorganic nano-phosphor embedded into silica matrix have shown great potential in novel chemical and biological sensor development due to their pure, intense and stable photoluminescence (PL) properties. However, their potential applications in forensic science, especially in latent fingerprint detection in particular, were still u...

This Special Section of the IEEE TRANSACTIONS ON NANOBIOSCIENCE comprises 9 accepted papers selected from the 2nd Engineering Sciences for Biology and Medicine Conference (ESBM 2015) organized in Tunisia from 1–3 May 2015. The conference received 52 contribution submissions from over 11 countries which went through a very rigorous review process. I...

Approved project Submitted by my PhD student Dr Ridha Elleuch. In the framework of the Mediterranean Science, Policy, Research & Innovation Gateway – MED-SPRING project – , UNIMED, is honored to present the selected authors and title of papers, whose contributions have been collected in a open-access e-book. Authors have been selected after a dedi...

Ho3+ ions doped tellurite-borate glass samples with varying compositions were prepared. The compositional dependence on phenomenological Judd-Ofelt parameters was compared in different kinds of rare earth ions doped tellurite-borate glasses. Two methods were used to obtain radiative transition probability of 5I7 level with the aim of assuring the f...

ZnO:Er3+,Yb3+ thin films with hexagonal wurtzite structure were successfully deposited on Si (111) substrates at 430°C by aerosol-assisted chemical vapor deposition (AACVD) atmospheric pressure process. Films were deposited with fixed 3 mol.% Erbium concentration and various Ytterbium concentrations of 6, 8, 9 and 10 mol.%. The annealing treatment...

Conference Proceeding of the ESBM2015

We synthesized Gd 2 O 3 and Gd 2 O 3 doped by europium (Eu) (2% to 10%) nanoplatelets using the polyol chemical method. The synthesized nanoplatelets were characterized by X-ray diffraction (XRD), FESEM, TEM, and EDX techniques. The optical properties of the synthesized nanoplatelets were investigated by photoluminescence spectroscopy. We also stud...

Submission Deadline 30/01/2015 Call for papers ESBM 2015 The international conference " Engineering Sciences in Biology and Medicine" ESBM'2015 will be organized in Monastir- Tunisia from 01 to 03 Mai 2015. You are invited to submit your abstract by 30 January 2015. Selected high quality research papers will be considered for publication after peer...

Final Program of the ESBM 2015 Conference

Erbium-doped yttrium-aluminum oxide films (Er:Y2O3-Al2O3) are deposited by aerosol-assisted metal-organic (AA-MO)CVD. The effects of the humidity of the carrier gas and UV assistance on their structure and optical properties during the deposition are investigated as a function of the substrate temperature and the aluminum mole fraction (Al2O3 mol.-...

Hexagonal wurtzite phased ZnO:Er3+/Yb3+ thin films with various Yb concentrations were deposited on Si(111) substrate by Aerosol Assisted Chemical Vapor Deposition process. Post-annealed films at 1000 °C in air atmosphere showed a crystallinity enhancement. Yb3+ (4F7/2 → 4F5/2) 1000 nm emission increased with the increase of Yb3+ concentration eman...

Nanocrystals (NC) of Pr3+:BaY2F8 with average diameter of 24nm have been successfully prepared by high-energy ball milling. The method is versatile, easily scalable and does not require the use of surfactants or catalysts. NC were prepared starting from high quality single crystal pieces and their spectroscopic features are analyzed and compared wi...

Rare earth-doped tellurite glasses are very attractive materials for laser and photonic applications, such as optical amplifiers. They have a good glass stability which leads to an enhancement of the radiative transition. In the present study, a new transparent bulk glass with the composition 85TeO2-5Nb2O5-5ZnO-5LiF doped with 1% Er2O3 (TNZL doped...

Y2Ti2O7:Er3+/Yb3+ (EYYTO) phosphors co-doped with Li+ ions were synthesized by a conventional solid-state ceramic method. The X-ray diffraction studies show that all the Li+ co-doped EYYTO samples are highly crystalline in nature with pyrochlore face centred cubic structure. The X-ray photon spectroscopy studies reveal that the incorporation of Li+...