Materials Science and Engineering / Malzeme Bilimi ve Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4719
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Article Citation - WoS: 49Citation - Scopus: 54Highly Porous Poly(o-Phenylenediamine) Loaded Magnetic Carboxymethyl Cellulose Hybrid Beads for Removal of Two Model Textile Dyes(Springer, 2022) Arıca, Tuğçe Aybüke; Balcı, Fadime Mert; Balcı, Sinan; Arıca, Mehmet YakupEnsuring the removal of complex dyes from wastewater is a topic of great interest as it is vital for the environment. The present study reports a facile preparation method for poly(o-phenylenediamine) [p(o-PDA)] micro-particles loaded to magnetic carboxymethyl cellulose (CMC) hydrogel beads as adsorbents. The prepared products were characterized by FTIR, TGA, VSM, SEM, BET, and zeta sizer. The Fe3O4@p(o-PDA)@CMC beads were used for the removal of Reactive Blue 4 (RB-4) and Congo Red (CR) textile dyes from an aqueous medium. Different factors, such as adsorbent dose, initial pH, ionic strength, contact time, temperatures, and initial RB-4 and CR concentrations were examined. The maximum adsorption capacities of the RB-4 dye and CR at optimum pH 5 reached 398.7 and 524.6 mg/g in 120 min, respectively. The adsorption of RB-4 and CR on the hybrid magnetic beads can be due to the electrostatic, hydrogen bonding, and π-π interactions. Moreover, the magnetic hybrid beads showed easy regeneration ability and good reusability. The adsorbent can be a very good candidate for the efficient removal of micro-pollutant from wastewater.Article Citation - WoS: 7Citation - Scopus: 6L2[gaxfa1–xpbi3]pbi4 (0 ≤ X ≤ 1) Ruddlesden–popper Perovskite Nanocrystals for Solar Cells and Light-Emitting Diodes(American Chemical Society, 2022) Güvenç, Çetin Meriç; Tunç, İlknur; Balcı, SinanThe main challenges to overcome for colloidal 2D Ruddlesden–Popper (RP) organo-lead iodide perovskite nanocrystals (NCs) are phase instability and low photoluminescence quantum yield (PLQY). Herein, we demonstrate colloidal synthesis of guanidinium (GA)-L2[GAPbI3]PbI4, formamidinium (FA)-L2[FAPbI3]PbI4, and GA and FA alloyed L2[GA0.5FA0.5PbI3]PbI4 NCs without using polar or high boiling point nonpolar solvents. Importantly, we show that optical properties and phase stability of L2[APbI3]PbI4 NCs can be affectively tuned by alloying with guanidinium and formamidinium cations. Additionally, the band gap of NCs can be rapidly engineered by bromide ion exchange in L2[GAxFA1–xPbI3]PbI4 (0 ≤ x ≤ 1) NCs. Our approach produces a stable dispersion of L2[FAPbI3]PbI4 NCs with 12.6% PLQY that is at least three times higher than the previously reported PLQY in the nanocrystals. Furthermore, L2[GAPbI3]PbI4 and L2[GA0.5FA0.5PbI3]PbI4 NC films exhibit improved ambient stability over 10 days, which is significantly higher than L2[FAPbI3]PbI4 NC films, which transform to an undesired 1D phase within 6 days. The colloidally synthesized guanidinium- and formamidinium-based 2D RP organo-lead iodide perovskite NCs with improved stability and high PLQY demonstrated in this study may find applications in solar cells and light-emitting diodes. Therefore, large A-site cation-alloyed 2D RP perovskite NCs may provide a new way to rationalize high-performance and stable perovskite solar cells and light-emitting diodes.Article Citation - WoS: 7Citation - Scopus: 8Seed-Mediated Synthesis of Colloidal 2d Halide Perovskite Nanoplatelets(Wiley, 2021) Güvenç, Çetin Meriç; Balcı, SinanColloidal synthesis of two-dimensional lead halide perovskite nanoplatelets (2D LHP NPLs) with a general formula of L-2[APbX(3)](n-1)PbX4 has been widely performed by using hot-injection or ligand assisted reprecipitation methods. Herein, for the first time, we report on seed-mediated synthesis of two and three monolayers (n=2, 3) lead halide perovskite nanoplatelets without using A-site cation halide salt (AX; A=Cesium, methylammonium, formamidinium and, X=Cl, Br, I) and long chain alkylammonium halide salts (LX; L=oleylammonium, octylammonium, butylammonium and, X=Cl, Br, I). The nanocrystal seeds have been prepared by reacting lead (II) halide salt and coordinating ligands in a nonpolar solvent and then they have been reacted with cesium oleate, formamidinium oleate or methylamine. Our facile synthesis route enabling further understanding of the growth dynamics of LHP NPLs provides highly stable, monodisperse NPLs with very narrow absorption and emission linewidths (min. 68 meV), and high PLQY (max. 37.6%).Article Citation - WoS: 12Citation - Scopus: 14Laser Assisted Synthesis of Anisotropic Metal Nanocrystals and Strong Light-Matter Coupling in Decahedral Bimetallic Nanocrystals(Royal Society of Chemistry, 2021) Mert Balcı, Fadime; Sarısözen, Sema; Polat, Nahit; Güvenç, Çetin Meriç; Karadeniz, Uğur; Tertemiz, Necip Ayhan; Balcı, SinanThe advances in colloid chemistry and nanofabrication allowed us to synthesize noble monometallic and bimetallic nanocrystals with tunable optical properties in the visible and near infrared region of the electromagnetic spectrum. In the strong coupling regime, surface plasmon polaritons (SPPs) of metal nanoparticles interact with excitons of quantum dots or organic dyes and plasmon-exciton hybrid states called plexcitons are formed. Until now, various shaped metal nanoparticles such as nanorods, core-shell nanoparticles, hollow nanoparticles, nanoprisms, nanodisks, nanorings, and nanobipyramids have been synthesized to generate plasmon-exciton mixed states. However, in order to boost plasmon-exciton interaction at nanoscale dimensions and expand the application of plexcitonic nanocrystals in a variety of fields such as solar cells, light emitting diodes, and nanolasers, new plexcitonic nanocrystals with outstanding optical and chemical properties remain a key goal and challenge. Here we report laser-assisted synthesis of decahedral shaped noble metal nanocrystals, tuning optical properties of the decahedral shaped nanocrystals by galvanic replacement reactions, colloidal synthesis of bimetallic decahedral shaped plexcitonic nanocrystals, and strong plasmon-plasmon interaction in bimetallic decahedral shaped noble metal nanocrystals near a metal film. We photochemically synthesize decahedral Ag nanoparticles from spherical silver nanoparticles by using a 488 nm laser. The laser assisted synthesis of silver nanoparticles yields decahedral (bicolored) and prism (monocolored) shaped silver nanocrystals. The decahedral shaped nanoparticles were selectively separated from prism shaped nanoparticles by centrifugation. The optical properties of decahedral nanocrystals were tuned by the galvanic replacement reaction between gold ions and silver atoms. Excitons of J-aggregate dyes and SPPs of decahedral bimetallic nanoparticles strongly couple and hence decahedral shaped plexcitonic nanoparticles are prepared. In addition, localized SPPs of decahedral shaped bimetallic nanocrystals interact strongly with the propagating SPPs of a flat silver film and hence new hybrid plasmonic modes (plasmonic nanocavities) are generated. The experimental results are further fully corroborated by theoretical calculations including decahedral shaped plexcitonic nanoparticles and decahedral nanoparticles coupled to flat metal films.Article Citation - WoS: 18Citation - Scopus: 46Phosphor-Based White Led by Various Glassy Particles:control Over Luminous Efficiency(The Optical Society, 2019) Yüce, Hürriyet; Güner, Tuğrul; Balcı, Sinan; Demir, Mustafa MuammerGenerating white light through a mainstream remote phosphor design suffers from phosphor conversion efficiency loss due to a backscattering of light. Such a loss also reduces luminous efficiency of the resulting white light. To overcome this issue, various glassy scatterers with different morphologies such as glass bubbles, glass beads, and nanosized silica particles were employed as scatterers, together with a fixed amount of yellow phosphor (YAG:Ce3+) and a poly(dimethylsiloxane) (PDMS) matrix. In addition, the simulation of the system validates the rigorous multiple scattering of the incoming light most probably due to refractive index mismatch between the glass bubbles and surrounding PDMS matrix along with the internal reflections. (C) 2019 Optical Society of America