Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
6 results
Search Results
Article Citation - WoS: 101Citation - Scopus: 105Defect-Engineering Agsbte2 With High Thermoelectric Performance(Wiley, 2023) Zhang, Yu; Li, Zhi; Singh, Saurabh; Nozariasbmarz, Amin; Li, Wenjie; Genç, Aziz; Xia, YiThermoelectric (TE) generators enable the direct and reversible conversion between heat and electricity, providing applications in both refrigeration and power generation. In the last decade, several TE materials with relatively high figures of merit (zT) have been reported in the low- and high-temperature regimes. However, there is an urgent demand for high-performance TE materials working in the mid-temperature range (400–700 K). Herein, p-type AgSbTe2 materials stabilized with S and Se co-doping are demonstrated to exhibit an outstanding maximum figure of merit (zTmax) of 2.3 at 673 K and an average figure of merit (zTave) of 1.59 over the wide temperature range of 300–673 K. This exceptional performance arises from an enhanced carrier density resulting from a higher concentration of silver vacancies, a vastly improved Seebeck coefficient enabled by the flattening of the valence band maximum and the inhibited formation of n-type Ag2Te, and ahighly improved stability beyond 673 K. The optimized material is used to fabricate a single-leg device with efficiencies up to 13.3% and a unicouple TE device reaching energy conversion efficiencies up to 12.3% at a temperature difference of 370 K. These results highlight an effective strategy to engineer high-performance TE material in the mid-temperature range.Article Citation - WoS: 10Citation - Scopus: 9Recyclability of Cspbbr3 Quantum Dot Glass Nanocomposites for Their Long-Standing Use in White Leds(2022) Vahedigharehchopogh, Naji; Erol, Erdinç; Kıbrıslı, Orhan; Genç, Aziz; Çelikbilek Ersundu, Miray; Ersundu, Ali ErçinThe embedding of CsPbBr3 perovskite quantum dots (PQDs) in an inorganic glass matrix not only protects them against chemical, thermal, and photodegradation but also provides an effective strategy to isolate toxic elements such as Pb from the environment for a long period of time. Herein, the recyclability of glass is another important feature that contributes to environmental sustainability. Hence, effective and efficient recycling technologies are needed for the widespread use of PQD glass nanocomposites (GNCs) in many commercial applications. However, studies on the recyclability of CsPbBr3 PQD GNCs have not been conducted so far. Therefore, in this work, we investigate the structural, thermal, optical, and photoluminescence properties of recycled CsPbBr3 PQD GNCs to assess their suitability as long-standing and reusable luminescent materials. For this purpose, the recyclability of GNCs is checked by three repeated melt-quenching and subsequent heat-treatment processes. Although the color emission properties of GNCs under the same heat-treatment conditions show a slight variation after each recycling step, PQD GNCs almost retain their PLQY even after the last recycling step. Ultimately, a prototype white light-emitting diode is constructed by coupling recycled PQD GNCs and a commercial red phosphor on top of a blue LED chip showing high-performance with CIE color coordinates of x = 0.3228, y = 0.3470 and a CCT value of 5920 K. The findings of this work reveal that the recyclability of PQD GNCs holds great promise for a more sustainable technology.Article Citation - WoS: 16Citation - Scopus: 16Exploiting the Lability of Metal Halide Perovskites for Doping Semiconductor Nanocomposites(American Chemical Society, 2021) Calcabrini, Mariano; Genç, Aziz; Liu, Yu; Kleinhanns, Tobias; Lee, Seungho; Dirin, Dmitry N.; Akkerman, Quinten A.Cesium lead halides have intrinsically unstable crystal lattices and easily transform within perovskite and nonperovskite structures. In this work, we explore the conversion of the perovskite CsPbBr3 into Cs4PbBr6 in the presence of PbS at 450 degrees C to produce doped nanocrystal-based composites with embedded Cs4PbBr6 nanoprecipitates. We show that PbBr2 is extracted from CsPbBr3 and diffuses into the PbS lattice with a consequent increase in the concentration of free charge carriers. This new doping strategy enables the adjustment of the density of charge carriers between 10(19) and 10(20) cm(-3), and it may serve as a general strategy for doping other nanocrystal-based semiconductors.Article Citation - WoS: 9Citation - Scopus: 11Synthesis, Bottom Up Assembly and Thermoelectric Properties of Sb-Doped Pbs Nanocrystal Building Blocks(MDPI, 2021) Cadavid, Doris; Wei, Kaya; Liu, Yu; Zhang, Yu; Li, Mengyao; Genc, Aziz; Berestok, TaisiiaThe precise engineering of thermoelectric materials using nanocrystals as their building blocks has proven to be an excellent strategy to increase energy conversion efficiency. Here we present a synthetic route to produce Sb-doped PbS colloidal nanoparticles. These nanoparticles are then consolidated into nanocrystalline PbS:Sb using spark plasma sintering. We demonstrate that the introduction of Sb significantly influences the size, geometry, crystal lattice and especially the carrier concentration of PbS. The increase of charge carrier concentration achieved with the introduction of Sb translates into an increase of the electrical and thermal conductivities and a decrease of the Seebeck coefficient. Overall, PbS:Sb nanomaterial were characterized by two-fold higher thermoelectric figures of merit than undoped PbS.Article Citation - WoS: 44Citation - Scopus: 38The Importance of Surface Adsorbates in Solution-Processed Thermoelectric Materials: The Case of Snse(Wiley, 2021) Liu, Yu; Calcabrini, Mariano; Yu, Yuan; Genç, Aziz; Chang, Cheng; Costanzo, Tommaso; Kleinhanns, TobiasSolution synthesis of particles emerges as an alternative to prepare thermoelectric materials with less demanding processing conditions than conventional solid-state synthetic methods. However, solution synthesis generally involves the presence of additional molecules or ions belonging to the precursors or added to enable solubility and/or regulate nucleation and growth. These molecules or ions can end up in the particles as surface adsorbates and interfere in the material properties. This work demonstrates that ionic adsorbates, in particular Na+ ions, are electrostatically adsorbed in SnSe particles synthesized in water and play a crucial role not only in directing the material nano/microstructure but also in determining the transport properties of the consolidated material. In dense pellets prepared by sintering SnSe particles, Na remains within the crystal lattice as dopant, in dislocations, precipitates, and forming grain boundary complexions. These results highlight the importance of considering all the possible unintentional impurities to establish proper structure-property relationships and control material properties in solution-processed thermoelectric materials.Article Citation - WoS: 40Citation - Scopus: 44Plasmon-Enhanced Photocatalytic and Antibacterial Activity of Gold Nanoparticles-Decorated Hematite Nanostructures(Elsevier Ltd., 2021) Emre, Alp; İmamoğlu, Rizvan; Savacı, Umut; Turan, Servet; Kazmalı, M. Kürşat; Genç, AzizHematite (alpha-Fe2O3) nanoparticles have received significant attention from the researchers due to their favorable and desirable properties in diverse applications. In the present study, single-crystalline hematite pseudo-nanocubes and porous nanorods were synthesized by the hydrothermal route without the usage of any surfactant agents, which were then decorated with gold nanoparticles hidrothermally in an aqueous solution in order to increase the solar energy conversion efficiency. The photocatalytic activities of synthesized nanoparticles were studied against Rhodamine B (RhB) under the illumination of AM 1.5 solar simulator. The excellent photocatalytic efficiency was obtained by changing morphological features of hematite nanostructures, along with the photocatalytic performance enhancement up to 25% thanks to the surface plasmon resonances for the gold nanoparticles-decorated hematite nanostructures. For instance, gold-nanoparticles decorated hematite pseudo-nanocubes almost completely degraded all the RhB after 30 min of illumination. It was also observed that all hematite products, with and without gold decoration, exhibited an impressive antibacterial effect and showed the lethal effect in E.coli. The same nanoparticles being photocatalytically active for organic pollutant degradation and having antibacterial effect may have a good potential for waste water remediation applications. (C) 2020 Elsevier B.V. All rights reserved.