Synergistic Influence of FRET on a High Quantum Yield π- Conjugate Polycarbazole-ZnS Composite Thin Film.

The incorporation of semiconducting materials into the π-conjugate polymer improves the optical, thermal, electrical, and electrochemical properties of optoelectronic devices. In this study, polycarbazole-zinc sulfide (PCZ) composites are synthesized via an in situ polymerization process, and their thin films are produced by spin coating. ZnS enhances the charge transfer qualities of polycarbazoles, which in turn results in better photophysical and electrical characteristics. The PCZ15 thin film has an optical band gap of 2.44 eV, a refractive index of 2.15, and an Urbach energy of 0.44 eV. Relative quantum yield for the PCZ15 was 38.4%, while Förster resonance energy transfer efficiency was 2%. Excellent thermal performance was shown by the PCZ15, which was 37.04% more efficient than the pure polycarbazole with an activation energy of 356 kJ/mol. PCZ15 has an outstanding charge mobility of 54.22 m2/(V s) and a conductivity of 0.298 S/cm. High charge transfer efficiencies were discovered by electrochemical analysis, which had a specific capacitance of 116 Fg-1. These characteristics strongly supported the viability of the PCZ15 thin film as a high-performance polymer-derived composite materials for optoelectronic devices.

FRET mechanism to enhance the quantum yield of the PCz/gC3N4 nanocomposite, an emissive material for OLED applications.

Conjugated polymers such as polycarbazole (PCz) have captivated more attention than other carbazole-based derivatives due to their superior electrical and optical properties. Accordingly, we synthesized PCz/gC3N4 nanocomposites via the in situ polymerization method using FeCl3 as the oxidative reagent. The synthesized nanocomposites were subjected to characterization techniques to examine their optical and electrical parameters and decide whether the materials were suitable as emissive materials. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were carried out to ascertain the crystalline or amorphous nature, surface interactions, and functional groups present in them. The surface microstructural and topographical investigations were conducted using field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (HRTEM) techniques. Optical parameters, such as refractive index ∼2.06, optical absorbance, optical band energy ∼2.77 eV, and the photoluminescence emission range, were studied using UV-Visible and photoluminescence spectrometry. The theoretical relative emission quantum yield of ∼67.9% and 87.7% energy transfer from the donor to the acceptor ion via the Förster energy transfer mechanism are illustrated by the PL data. The Förster energy transfer mechanism has been elaborated. The carrier mobility ∼32.03 m2 V-1 S-1, sheet resistance ∼1.6977 × 102 Ω m, carrier density ∼11.96 × 1014 cm-3 and conductivity ∼5.90 × 10-3 S cm-1 were computed using Hall effect measurements. The dielectric constant, dielectric loss, and IV characteristic curve were estimated by the LCR and Four-probe IV measurement methods. The high PL emission intensity, CIE coordinates in the blue emission region, and the CCT value indicate that it is a suitable emissive layer material for OLED applications.

Tuning the optical properties of high quantum-yield g-C3N4 with the inclusion of ZnS via FRET for high electron-hole recombination.

Luminescent polymeric graphitic composites have the potential to be efficient energy converters for sophisticated displays and light sources. Thermal condensation is used to synthesize g-C3N4-ZnS composites. The XRD, and FTIR analyses confirmed the synthesis of the pure host, filler, and composites. FESEM, and TEM images revealed that the ZnS nanosheets were evenly distributed over the g-C3N4 sheets. As a result of ZnS incorporation, the melting point of g-C3N4 has been raised to 748.5 °C, and the thermal stability of gZ has been increased by 27 %. The optimized gZ15 band gap is determined to be 2.98 eV with a crystallite size of 4.2 nm and a micro stain of 35.42 × 10-3. With a purity of 63.4 %, gZ15 demonstrated a significant rate of recombination in the blue region. gZ15 has a high PLQY of 98 % and a FRET efficiency of 92%. All of the improved properties demonstrated that polymeric g-C3N4-ZnS was the optimum materials for usage in the active or emissive layer of optoelectronic devices.

Nanocrystalline ß-NiS: a redox-mediated electrode in aqueous electrolyte for pseudocapacitor/supercapacitor applications.

Currently, enhancing the performance of electrochemical supercapacitors is the subject of intense research to fulfill the ever-increasing demand for grid-scale energy storage and delivery solution, thereby utilizing the full potential of renewable energy resources and decreasing our dependence on fossil fuels. Metal sulfides, such as cobalt sulfide (CoS), nickel sulfide (NiS), molybdenum sulfide (MoS), copper sulfide (CuS), and others, have recently emerged as a promising class of active electrode materials, alongside other supercapacitor electrode materials, due to their relatively high specific capacitance values and exceptional reversible redox reaction activities. The synthesis, characterizations, and electrochemical performances of single-phase nanocrystalline ß-NiS are presented here and the electrode based on this material shows a specific capacitance of 1578 F g-1 at 1 A g-1 from the galvanostatic discharge profile, whereas a capacitance of 1611 F g-1 at 1 mV s-1 was obtained through the CV curve in 2 M KOH aqueous electrolyte. Additionally, the electrode also performs well in neutral 0.5 M Na2SO4 electrolytes resulting in specific capacitance equivalent to 403 F g-1 at 1 mV s-1 scan rate. The high charge storage capacity of the material is due to the superior intercalative (inner) charge storage coupled with the surface (outer) charges stored by the ß-NiS electrode and was found to be 72% and 28%, respectively, in aqueous 2 M KOH electrolyte. This intercalative charge storage mechanism is also responsible for its excellent cycling stability. Additionally, we assembled aqueous asymmetric supercapacitors (ASCs) with activated carbon (AC) as the negative electrode and the ß-NiS electrode as the positive electrode. The combination of the ß-NiS electrode and AC with excellent cycling stability resulted in the highest specific energy equivalent to ∼163 W h kg-1 and a specific power of ∼507 W kg-1 at 1 A g-1 current rate.