A novel fabrication of electrospun polyacrylonitrile/NaYF4:Eu+3 light emitting nanofibers

Multifaceted enhancement of piezoelectricity and optical fluorescence in electrospun PVDF-ceria nanocomposite

This study investigates the enhancement of piezoelectric and optical fluorescence properties in electrospun polyvinylidene fluoride (PVDF) nanocomposite membranes doped with cerium oxide (Ce3+) at varying weight percentages. An optical characterisation using absorbance analysis found a blue shift in the bandgap of the ceria NPs, which also enhanced UV absorption in the PVDF polymer. At some additive doses, luminosity analysis demonstrated an incremental fluorescence impact. However, above a certain point, additional increases seemed to have a quenching effect, which decreased fluorescence. FTIR based analysis revealed the enhanced β sheets content to 61.75% in the sample of PVDF with a ceria 5 wt%. The fabricated nanofiber membrane displayed an average fiber diameter of around 108 nm. XRD analysis confirms that the incorporation of Ce3+ significantly promotes the formation of the β-phase in PVDF, thereby improving its piezoelectric response. Additionally, water contact angle measurements indicate increased hydrophobicity in the nanocomposite membranes, expanding their applicability in sensing and energy harvesting applications. ICP-OES and XRF analysis confirm that Ce was successfully incorporated with the PVDF chain. The dual role of ceria as both a nucleating agent for β-phase formation and an optical fluorescence enhancer highlights its potential for the development of multifunctional nanocomposites. This work presents a novel approach to engineering PVDF-based materials with enhanced piezoelectricity and optical fluorescence for advanced technological applications. This ultrasensitive PVDF with a ceria 5 wt% nanogenerator demonstrated pronounced piezoactivity, generating a maximum of 9 V with 3 N load at 1.5 Hz frequency which is almost three times of the output generated by pure PVDF. The formed oxygen vacancies according to tri-valent cerium ions, which have been showed through optical characteristics, supports the nucleation of PVDF chains around ceria NPs. The resultant PVDF/ceria nanomembrane demonstrated a remarkable maximum power density of 89 mW/m2, demonstrating its load-bearing capability. With its dual functionality as an optical sensor and an energy harvesting unit, this adaptable nanocomposite shows potential for use in multifunctional devices.

Electrospun network based on polyacrylonitrile-polyphenyl/titanium oxide nanofibers for high-performance supercapacitor device

Nanofibers and mat-like polyacrylonitrile-polyphenyl/titanium oxide (PAN-Pph./TiO2) with proper electrochemical properties were fabricated via a single-step electrospinning technique for supercapacitor application. Scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), thermogravimetry (TGA), fourier transform infrared (FTIR), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) were conducted to characterize the morphological and chemical composition of all fabricated nanofibers. Furthermore, the electrochemical activity of the fabricated nanofibers for energy storage applications (supercapacitor) was probed by cyclic voltammetry (CV), charge-discharge (CD), and electrochemical impedance spectroscopy (EIS). The PAN-PPh./TiO2 nanofiber electrode revealed a proper specific capacitance of 484 F g-1 at a current density of 11.0 A g-1 compared with PAN (198 F g-1), and PAN-PPh. (352 F g-1) nanofibers using the charge-discharge technique. Furthermore, the PAN-PPh./TiO2 nanofiber electrode displayed a proper energy density of 16.8 Wh kg-1 at a power density (P) of 2749.1 Wkg-1. Moreover, the PAN-PPh./TiO2 nanofiber electrode has a low electrical resistance of 23.72 Ω, and outstanding cycling stability of 79.38% capacitance retention after 3000 cycles.

Fluorescence regulation derived from Eu3+in miscible-order fluoride-phosphate blocky phosphor

Miscible-order fluoride-phosphate blocky phosphor (FBP), composed with ordered-phase of NaYF₄crystals and unordered phase of tin-fluorophosphate glass, is prepared by a two-step process and luminescent properties of FBPs embedded with different particle sizes of NaYF₄crystals are presented. High-frequency fluorescence from higher metastable⁵D_J(J = 1, 2 and 3) energy levels are effectively released in Eu³⁺doped fluoride crystals. Taking the blue emission of Sn²⁺as the framework, multi-peak emissions from metastable energy levels are controlled to adjust the color coordinates of the FBP to the white-light region, which the color rendering index (CRI) reaches 89. Tunable color FBP with high CRI retains splendid luminescence property of fluoride, providing a potential candidate for the development of white LED.