Ali Karatutlu

Metal–organic bimetallic frameworks of Ni–Co, having metal content of 2:1 and 1:2 molar ratios, respectively, have been synthesized via a rapid laser method with a continuous-wave Nd:YVO₄ laser (λ = 975 nm) under 88–90 °C in a DMF/H₂O solution in 70 min. The structure, porosity, and photophysical, electrochemical, and dielectric characteristics of the frameworks and their reduced graphene oxide (rGO) composites in the form of powders and UV-cured PEGMEA/PEGDA films have been investigated. Framework Ni2Co1MOF demonstrated a BET surface area equal to 88.3 m² g⁻¹ and a total pore volume of 0.022 cm³ g⁻¹, whereas framework Ni1Co2MOF exhibited a BET surface area of 52.5 m² g⁻¹ and a total pore volume of 0.016 cm³ g⁻¹. The incorporation of rGO from 1 to 10 wt.% into the framework changed the charge transport and polarization properties of the materials. The electrochemical investigations of the 10 wt.% rGO-Ni1Co2MOF composite in 0.5 M HCl demonstrated a specific capacitance of 32.3 F g⁻¹ at 10 mV s⁻¹, and it preserved 98% of the electrochemical response after 400 cycles, in comparison with 96% for the 10 wt.% rGO-Ni2Co1MOF. The electrochemical responses consisted of both diffusion-controlled ion transport and pseudocapacitance. The introduction of rGO in 1 to 10 wt.% in the polymer composite improved the conductivity and Maxwell–Wagner–Sillars interface polarization at low frequencies in the case of low rGO concentrations, whereas overly high rGO content led to aggregation and the decreased influence of the conductive phase. The main contribution of the present work is the fast sub-100 °C synthesis approach for compositionally tunable Ni-Co frameworks/rGO materials and the relationships between the metal ratio, porous structure, interfacial charge transport, and dielectric response.

In this study, amorphous germanium (a‐Ge) thin films on a Kapton tape are fabricated and utilized in monitoring gamma (γ)‐ray irradiation. The flexible Ge thin films are formed using electron beam evaporation without heating of the chamber with a rate of 0.01 Å s ⁻¹ . Ultraviolet‐visible‐near‐infrared (UV–vis–NIR) absorption and Raman spectroscopy studies confirm the absorption from the UV to NIR regions and amorphous nature of the thin films, respectively. The X‐ray diffraction and the extended X‐ray absorption fine structure studies demonstrate the atomic structure of a‐Ge thin films, which suggests the possible presence of the macrobending created due of the flexible Kapton tape. The samples are exposed to the γ‐rays with a relatively higher dose up to 5 kGy compared to previous typical values exposed to test Ge‐based thin films. The samples are exposed to the γ‐rays with a dose of 1, 3, 4, and 5 kGy. The structural and optical changes upon the exposure of the γ‐rays demonstrate that flexible Ge thin film can be used in the radiation monitoring up to a dose level of 12 kGy.

This comprehensive book chapter delves into cutting-edge advancements in the field of ceramics for photonic applications, a field poised to revolutionize light manipulation and control. The chapter explores the unique properties and synthesis methods of these advanced ceramic materials, which make them ideal for developing innovative photonic devices. The chapter highlights critical areas like photonic crystals, nonlinear optics, integrated photonics, and biophotonic ceramics, showcasing their applications in high-performance optics, sensing, energy harvesting, and biomedicine. We also delve into the potential of transparent ceramics, ceramic upconversion nanoparticles (UCNP), transparent glass/ceramics, rare-earth doped ceramics, and ceramic metamaterials, highlighting the diverse applications of these advanced ceramic materials. By examining the latest research and developments in this rapidly evolving field, the chapter aims to provide a detailed overview of how ceramics can impact photonic technologies and shape the future direction of light-based technologies. Through a thorough review of these materials’ properties, synthesis techniques, and applications, this chapter serves as a valuable resource for researchers, scientists, and professionals interested in the intersection of ceramics and photonics.

Metal‐organic frameworks (MOFs) are porous materials with numerous chemical and structural possibilities. Due to their ease of modification, well‐organized structure, and diverse guest molecule chemistry, MOFs are ideal platforms for uncovering improved functional material design characteristics. Quantitative analysis of glucose is crucial, especially in some food products, for quality control as well as evaluation of the glucose levels helps diagnose and treat diabetes. Recent glucose sensing devices have relied heavily on MOFs and other nanomaterials to enable user‐friendly and safe non‐invasive sensing methods. Nevertheless, the conventional synthesis methods involve multi‐day reactions, cooling, and depressurization processes. This study demonstrates the unprecedented high‐power laser‐induced rapid synthesis (LIRS) of Ni‐based MOF nanospheres with interconnected nano‐rods and noncentrosymmetric primitive triclinic crystalline structure, highlighting their multifunctional usage in sensing and gas sorption applications. Ab initio simulations show excellent agreement with the experimental physical and gas sorption properties. Furthermore, the Ni‐MOF‐based biosensor accurately measures glucose real‐life beverage samples, yielding promising glucose detection biosensor results with a low limit of the detection (LOD) of 13.96 µM and high sensitivity of 120.606 µA mM ⁻¹ cm ⁻² .

Optical tunability and repeatability are essential in fabricating optoelectronic devices from waveguides to Bragg gratings (BGs) for high‐energy, high‐power, mode‐locking, and sensing applications. For this purpose, a controlled adjustment in the optical properties, including the refractive index of the deposited nanolayers, becomes critical. This study reveals that silicon oxynitride (SiON) doping into silicon (Si) offers a new way for the preparation of novel Si‐based devices with an emphasis on the BGs for filtering a particular portion of an electromagnetic spectrum, including the wavelengths of 800, 976, 1550, and 1840 nm. Control on the incident angle dependence of the BGs is demonstrated at Watt‐level for the wavelength of 976 nm. Amorphous SiON‐doped Si layers on alternating SiO₂ can be synthesized on bulk substrates and different optical fibers at relatively low temperatures with wide and narrow bandwidths. The high reflectivity of the novel Si‐based BGs reveals over −22 dB reflection using typical optical fibers, including standardsingle‐mode fibers and high‐birefringent polarization‐maintaining (PM) fibers. The polarized transmission measurement over the BG on the PMfiber shows the BGs do not deteriorate the PM properties, strongly yielding a beat length of 1.68 mm and birefringence of 9.2 × 10⁻⁴ at the telecom C band.