Photoluminescent electrospun polymeric nanofibers incorporating germanium nanocrystals

Abstract

a b s t r a c tThe photoluminescent germanium nanocrystals (Ge-NCs) were successfully incorporated into electrospun polymeric nanofiber matrix in order to develop photoluminescent nanofibrous composite web. In the first step, the synthesis of Ge-NCs was achieved by nanosecond pulsed laser ablation of bulk germanium wafer immersed in organic liquid. The size, the structural and the chemical characteristics of GeNCs investigated by TEM, XPS, XRD and Raman spectroscopy revealed that the Ge-NCs were highly pure and highly crystalline having spherical shape within 3-20 nm particle size distribution. In the second step, Ge-NCs were mixed with polyvinyl alcohol (PVA) polymer solution, and then, Ge-NC/PVA nanofibers were obtained via electrospinning technique. The electrospinning of Ge-NCs/PVA nanoweb composite structure was successful and bead-free Ge-NCs/PVA nanofibers having average fiber diameter of 185 ± 40 nm were obtained. The STEM analysis of the electrospun Ge-NCs/PVA nanofibers elucidated that the Ge-NCs were distributed homogeneously in the polymeric nanofiber matrix. The UV-Vis absorption and photoluminescence spectroscopy studies indicated the quantum confinement effect of Ge-NCs on the optical properties of the electrospun Ge-NCs/PVA nanoweb.

Pulsed laser ablation of Germanium under vacuum and hydrogen environments at various fluences

“…This peak corresponds to optical vibration of Ge-Ge band which proves the crystalline behavior of Ge [34,35]. A slight shift in Raman peak is observed at wave number of 297 cm −1 at fluence of 4.5 J cm −2 which also represents crystalline Ge [36]. This peak shifting is attributed to laser induced stresses generated in Ge crystal [37,38].…”

Uniform Luminous Perovskite Nanofibers with Color‐Tunability and Improved Stability Prepared by One‐Step Core/Shell Electrospinning

“…It was reported that the energy spectrum of an emissive compound became discrete as its dimension was reduced to nanoscale (tens nanometer). Consequently, not only the resulting bandgap was size‐dependent but also the photoluminescence (PL) would be blue‐shifted and intensified with the decrease of the nanocrystal's size, known as the quantum confinement . Thus far, versatile methods have been explored to modulate the nanostructure of perovskite materials, especially by means of controlling the stoichiometry of the perovskite precursors.…”

Nanoparticles, Nanocrystals, and Nanocomposites Produced with Pulsed Laser Ablation and Their Applications

“…PLAL method offers pure and agent-free NP generation. The photoluminescent Ge-NCs synthesis was demonstrated by ns-PLAL method; then, the Ge-NCs were merged into the electrospun polymeric nanofiber matrix to generate functional nanofibrous composite web [33]. The generated functional nanocomposites are represented in Figure 3.…”

“…SEM images of (a) PVA nanofibers, (b) Ge-NCs/PVA nanofibers (the insets represent the high magnification SEM images), (c) STEM image of Ge-NCs/PVA nanofiber[33], (d) EDX data of Ge-NCs/PVA.…”