In Situ Fabrication of Lead-Free Cs₃Cu₂I₅ Nanostructures Embedded in Poly(Vinylidene Fluoride) Electrospun Fibers for Polarized Emission

Abstract

Polarized emissive materials with anisotropic nanostructures have attracted tremendous attention as potential substitutes for polarizers. Herein, the electrospinning technique is adopted to realize in situ fabrication of lead-free halide Cs 3 Cu 2 I 5 nanostructures embedded in poly(vinylidene fluoride) (PVDF) micro/ nanofiber films for polarized luminescence generation, with a photoluminescence quantum yield (PLQY) of 33.3−86.1%. The functionality of the polymer PVDF as a protector and its interactions with Cs 3 Cu 2 I 5 were demonstrated. The Cs 3 Cu 2 I 5 /PVDF composite nanofibers exhibit a higher degree of PL polarization ratio (P) than that of composite microfibers, reaching a highest P of 0.4 and long-term stability. This polarized emission is attributed to the directional transition dipole moment (TDM) induced by the asymmetric crystal structure of aligned Cs 3 Cu 2 I 5 nanorods and dielectric confinement effect of the PVDF matrix. The universality of the in situ electrospinning preparation strategy is confirmed by the fabrication of a Cs 3 Cu 2 I 5 /PVA fiber film with a P of 0.5. The reported Cs 3 Cu 2 I 5 /polymer nanofiber films with bright and highly polarized light emissions will have great potential for optoelectronic applications such as liquid crystal display (LCD) backlighting, spectrum splitting, waveguides, lasers, and polarized photodetectors.

Unraveling the Phase Transition and Luminescence Tuning of Pb-Free Cs–Cu–I Perovskites Enabled by Reaction Temperature and Polar Solvent

“…To date, different synthetic approaches have been developed to prepare Cs–Cu–I perovskites, such as colloidal chemical methods, antisolvent strategy, and mechanical grinding methods . The rapid progress made in the synthesis of Cs–Cu–I perovskites drove the development of their applications in light-emitting diodes, photodetectors, anticounterfeiting, and so on. − For example, researchers demonstrated that the reversible conversion between blue-emitting Cs 3 Cu 2 I 5 and yellow-emitting CsCu 2 I 3 through exposing or removing water exhibited excellent stability in the anticounterfeiting applications. , Yet, to date, few works have been reported on the relationship between luminescence tuning and phase transition of Cs–Cu–I perovskites on the nanoscale.…”

Ibuprofen-Loaded ZnO Nanoparticle/Polyacrylonitrile Nanofibers for Dual-Stimulus Sustained Release of Drugs

“…Numerous medicated nanoparticles have found their potential applications in drug delivery, while electrospinning has wide application prospects in the field of transdermal drug delivery. − Electrospinning is able to treat many kinds of fluids, including solutions, , emulsions, , and nano-suspensions, , and in several manners such as blending, , coaxial, and multiple fluid . Drug-loaded electrospun nanofiber membranes have large specific surface areas, high porosity, and high fluid absorption, which induce a humid environment on the skin cuticle, allowing the fiber membrane to closely fit to the skin, thereby helping drugs enter systemic circulation in the way of dissimilar diffusion along a concentration gradient. − Polyacrylonitrile (PAN) is widely used for electrospinning because of its good electrospinnability and stability .…”

Lead-Free Inorganic Nanoparticles of Perovskite Embedded within Waterproof Nanofiber Films for White Color Emission

“…Several methods are suggested for improving the stability of perovskite materials through polymer coating with waterproof materials 19 or encapsulation within a polymer matrix. 20,24 without organic surfactants via electrospinning of a PS and CsI/CuI precursor solution. The perovskites within PS provide uniform yellow and blue emission with a wide full width at half-maximum (FWHM).…”

“…Cesium copper halide perovskites (Cs–Cu–X) are representative light-emitting materials that are low-cost and earth-abundant, and provide eco-friendly broad-band emission. The synthesis of Cs–Cu–X compounds has been accomplished using solvent evaporation, mechanochemical reactions, , QDs in surfactants, , melt growth, and vapor codeposition, , which could be used in optoelectronic applications such as anticounterfeiting, , polarization, and white light-emitting devices (WLEDs). , Despite the various advantages and applications mentioned above, Cs 3 Cu 2 I 5 perovskite has low stability in moisture, causing transformation into CsCu 2 I 3 and weak photoluminescence (PL) intensity. , …”

“…Polymer matrixes offer thermal, moisture, and oxidation stability to IPNC materials. Several methods are suggested for improving the stability of perovskite materials through polymer coating with waterproof materials or encapsulation within a polymer matrix. , Shi et al demonstrated the reversible conversion between blue-emissive Cs 3 Cu 2 I 5 and yellow-emissive CsCu 2 I 3 and a poly­(methyl methacrylate) (PMMA) layer, which gives blue-emissive Cs 3 Cu 2 I 5 long-term stability in water. Wang et al fabricated Cs 3 Cu 2 I 5 encapsulated in poly­(vinylidene fluoride) (PVDF) nanofiber films by a one-step electrospinning technique.…”