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

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.