arXiv subjects

Muhammet S. Toprak

Publications and source records attributed to Muhammet S. Toprak.

3 recordsLinked to original sources

arXiv2026

Synergistic enhancement of Bi2Te3 Sb2Te3 PMMA thermoelectric generators via dithiol assisted conductivity and FEM based geometry optimization

In recent decades, thermoelectric (TE) materials have proven to be a complementary source of renewable energy, as they can directly convert waste heat into electrical energy. Energy-efficient, reliable, and scalable synthetic routes for the fabrication of TE materials and their processing into functional devices via low-energy and low-waste routes are necessary for the broader adoption of these materials in various applications. In this work, we report the formulation of hybrid thermoelectric (hTE) inks based on nanostructured Sb2Te3 and Bi2Te3, using PMMA as the polymer matrix and hexanedithiol (HDT) as the binder. Percolation studies were conducted to determine the optimal film composition, with an 80% nanoparticle content yielding the highest TE performance. Finite element modelling (FEM) was employed to optimize the device geometry, including the cross-sectional area ratio of p- and n-type legs, to maximize power output. Based on these results, a flexible hTEG was fabricated using the optimized ink composition. The device exhibited an output power of 950 nW and a Power Output Density (PoD) of 40.37 nW cm-2 under a 30 K temperature gradient, significantly outperforming previously reported polymer-based flexible hTEGs incorporating chalcogenides. This study presents a sustainable and effective strategy for developing high-performance hybrid thermoelectric devices through ink formulation, composition optimization, and simulation-guided device design.

physics.app-ph↗

arXiv2025

Scalable solution chemical synthesis and comprehensive analysis of Bi2Te3 and Sb2Te3

Thermoelectric (TE) materials can directly convert heat into electrical energy. However, they sustain costly production procedures and batch-to-batch performance variations. Therefore, developing scalable synthetic techniques for large-scale and reproducible quality TE materials is critical for advancing TE technology. This study developed a facile, high throughput, solution-chemical synthetic technique. Microwave-assisted thermolysis process, providing energy-efficient volumetric heating, was used for the synthesis of bismuth and antimony telluride (Bi2Te3, Sb2Te3). As-made materials were characterized using various techniques, including XRPD, SEM, TEM, XAS, and XPS. Detailed investigation of the local atomic structure of the synthesized Bi2Te3 and Sb2Te3 powder samples was conducted through synchrotron radiation XAS experiments. The sintered TE materials exhibited low thermal conductivity, achieving the highest TE figure-of-merit values of 0.7 (573 K) and 0.9 (523 K) for n-type Bi2Te3 and p-type Sb2Te3, respectively, shifted significantly to the high-temperature region when compared to earlier reports, highlighting their potential for power generation applications. The scalable, energyand time-efficient synthetic method developed, along with the demonstration of its potential for TE materials, opens the door for a wider application of these materials with minimal environmental impact.

physics.app-ph↗

arXiv2023

Size stability and self-agglomeration of erythrocyte-derived membrane nanovesicles versus physiological extracellular vesicles

Extracellular vesicles (EVs) and plasma membrane-derived exosome-mimetic nanovesicles demonstrate significant potential for drug delivery. Latter synthetic provides higher throughput over physiological EVs. However they face size-stability and self-agglomeration challenges in physiological solutions to be properly characterized and addressed. Here we demonstrate a fast and high-throughput nanovesicle screening methodology relying on dynamic light scattering (DLS) complemented by atomic force microscopy (AFM) measurements, suitable for the evaluation of hydrodynamic size instabilities and aggregation effects in nanovesicle solutions under varying experimental conditions and apply it to the analysis of bio-engineered nanovesicles derived from erythrocytes as well as physiological extracellular vesicles isolated from animal seminal plasma. The synthetic vesicles exhibit a significantly higher degree of agglomeration, with only 8 % of them falling within the typical extracellular vesicle size range (30-200 nm) in their original preparation conditions. Concurrent zeta potential measurements performed on both physiological and synthetic nanovesicles yielded values in the range of -17 to -22 mV, with no apparent correlation to their agglomeration tendencies. However, mild sonication and dilution were found to be effective means to restore the portion of EVs-like nanovesicles in synthetic preparations to values of 54% and 63%, respectively, The results illustrate the capability of this DLS-AFM-based analytical method for real-time, high-throughput and quantitative assessments of agglomeration effects and size instabilities in bioengineered nanovesicle solutions, providing a powerful and easy-to-use tool to gain insights to overcome such deleterious effects and leverage the full potential of this promising biocompatible drug-delivery carriers for a broad range of pharmaceutical applications.

physics.bio-ph↗