TY - JOUR

T1 - Perpendicular Alignment of 2D Nanoplatelet Emitters in Electrospun Fibers

T2 - A Result of the Barus Effect?

AU - Liu, Xu

AU - Li, Fuzhao

AU - Hohgardt, Manuel

AU - Klepzig, Lars Frederik

AU - Willich, Marcel Maximilian

AU - Christ, Henrik Alexander

AU - Schaate, Andreas

AU - Behrens, Peter

AU - Lauth, Jannika

AU - Menzel, Henning

AU - Walla, Peter Jomo

N1 - Funding Information: X.L., F.L., and M.H. contributed equally to this work. The authors thank Simone Schulz (Institute of Chemical and Thermal Process Engineering, Technische Universität Braunschweig) for taking SEM images and Stephanie Michel (Institute of Particle Technology, Technische Universität Braunschweig) for the AFM measurements. The authors thank Hartmut Sebesse (Communication and Media, Max‐Planck‐Institute for Multidisciplinary Sciences) for graphical assistance with Figure 4 . The authors also thank the Laboratory of Nano and Quantum Engineering (LNQE) in Hannover for access to the TEM. This research was funded by the German research foundation (Grants INST 188/334‐1 FUGG) and under Germany's Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453).

PY - 2023/9/15

Y1 - 2023/9/15

N2 - Stable jet electrospinning (SJES) is a special form of optical fiber generation that prevents chaotic fiber whipping typical for conventional electrospinning procedures. Incorporation of highly emissive semiconductor nanoplatelets (NPLs) in such fibers has very high potential in optical data transmission, optological circuits, fiber lasers, solar light concentrators and many other fields because NPLs exhibit strongly directed emission from their surface plane due to various in-plane transition dipole moments. However, potential orientation control of 2D-NPLs in SJES is entirely unknown as electric fields and various mechanical forces contribute in a complex manner simultaneously. Here, the observation of counter-intuitive yet very beneficial orientation of rectangular CdSe/CdS 2D-NLP in SJES perpendicular to the fiber drawing axis is reported. Scanning electron microscopy, 3D-single particle excitation polarization microscopy, 3D-photogoniometry, polarized emission spectroscopy and small angle X-ray scattering (SAXS) demonstrate aggregation free perpendicular alignment of the NPLs in poly(methyl methacrylate) (PMMA) fibers, resulting in dominant emission in directions parallel to the fiber. It is suggested that the observed vertical alignment is due to normal forces resulting from viscoelastic expansion when the polymer solution leaves the cannula (Barus effect) and that using such perpendicular nano-emitter alignment forces allows for the generation of novel materials also beyond fibers.

AB - Stable jet electrospinning (SJES) is a special form of optical fiber generation that prevents chaotic fiber whipping typical for conventional electrospinning procedures. Incorporation of highly emissive semiconductor nanoplatelets (NPLs) in such fibers has very high potential in optical data transmission, optological circuits, fiber lasers, solar light concentrators and many other fields because NPLs exhibit strongly directed emission from their surface plane due to various in-plane transition dipole moments. However, potential orientation control of 2D-NPLs in SJES is entirely unknown as electric fields and various mechanical forces contribute in a complex manner simultaneously. Here, the observation of counter-intuitive yet very beneficial orientation of rectangular CdSe/CdS 2D-NLP in SJES perpendicular to the fiber drawing axis is reported. Scanning electron microscopy, 3D-single particle excitation polarization microscopy, 3D-photogoniometry, polarized emission spectroscopy and small angle X-ray scattering (SAXS) demonstrate aggregation free perpendicular alignment of the NPLs in poly(methyl methacrylate) (PMMA) fibers, resulting in dominant emission in directions parallel to the fiber. It is suggested that the observed vertical alignment is due to normal forces resulting from viscoelastic expansion when the polymer solution leaves the cannula (Barus effect) and that using such perpendicular nano-emitter alignment forces allows for the generation of novel materials also beyond fibers.

KW - fiber optics

KW - light redirecting

KW - nanoparticle alignment

UR - http://www.scopus.com/inward/record.url?scp=85162011323&partnerID=8YFLogxK

U2 - 10.1002/mame.202300027

DO - 10.1002/mame.202300027

M3 - Article

AN - SCOPUS:85162011323

VL - 308

JO - Macromolecular Materials and Engineering

JF - Macromolecular Materials and Engineering

SN - 1438-7492

IS - 9

M1 - 2300027

ER -