Browsing by Subject "Lattices"
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Item Open Access Electrospun Fe2O3 entrenched SiO2 supported N and S dual incorporated TiO2 nanofibers derived from mixed polymeric template/surfactant: enriched mesoporosity within nanofibers, effective charge separation, and visible light photocatalysis activity(American Chemical Society, 2019) Pradhan, Amaresh C.; Uyar, TamerThe α-Fe2O3 promoted and SiO2 supported N and S dual incorporated TiO2 nanofibers (FeSiNST NFs) along with neat oxide NFs have been synthesized by electrospinning via sol–gel. The keen approach is that mixed polyvinylpyrrolidone (PVP) as template and cetyltrimethylammonium bromide (CTAB) as surfactant are responsible for the creation of mesoporosity within NFs. The photoluminescence (PL) spectrum and UV–visible diffuse reflectance spectroscopic (DRS) result revealed the role of α-Fe2O3 as catalytic promoter in FeSiNST NFs by suppressing electron–hole (e––h+) recombination, red shifting, and oxygen vacancies (Ovs). The design of FeSiNST NFs by combining with SiO2 as catalytic support and N and S as visible light absorbers in TiO2, beautifies the present study. The high photocurrent (3.2 mA/cm2), high Efb value (−1.0 V), and low Rct value (∼74 Ω) support the enhanced photocatalysis (photoreduction and photodegradation) by FeSiNST in visible light. Charge transfer phenomena, Ovs, mesoporosity, and separation of e––h+ are the vital factors for an effective photocatalysis achievement.Item Open Access Orbits in the anti-invariant sublattice of the K3-lattice(Bilkent University, 2005) Koca, CanerItem Open Access Thermodynamic silver doping of core/shell colloidal quantum wells imparted with paramagnetic properties emitting at near-infrared(American Chemical Society, 2023-05-29) Shabani, Farzan; Ahmad, Muhammad; Kumar, Satish; Delikanlı, Savaş; Işık, Furkan; Bhattacharya, A.; Petrou, A.; Demir, Hilmi VolkanTwo-dimensional (2D) core/shell nanoplatelets (NPLs) synthesized via the hot-injection method provide excellent thermal and chemical stability for high-temperature doping, where an expanded and flexible lattice is required. Here, a thermodynamic approach toward silver doping of these NPLs is proposed and demonstrated, which previously proved to be challenging due to the fast self-purification of the dopants with the introduction of the shell. Maintaining the doping procedure in the reversible regime ensured the integrity of the NPLs and allowed a high level of doping; however, the equilibrium condition is further complicated by environmental factors that affect the chemical activity of the cations and the surface composition of the NPLs. Two main deterioration mechanisms in the irreversible regime were observed: ZnS-shelled NPLs suffered preferential etching, while CdS-shelled NPLs underwent cleavage and fragmentation. Alloying of the shell minimized both mechanisms for CdZnS-shelled NPLs and preserved the metastable state of the NPLs, including their 2D shape and crystalline structure. Distribution of silver ions in the lattice of the NPLs directly affected the recombination dynamics and enabled fine-tuning of the near-infrared emission beside the exciton confinement. These silver-doped CdZnS-shelled NPLs are shown further to exhibit enhanced paramagnetic properties with Zeeman splitting and Brillouin-like bound-exciton polarization as a function of the magnetic field, critical for spintronic applications