Stretchable and Ambient Stable Perovskite/Polymer Luminous Hybrid Nanofibers of Multicolor Fiber Mats and Their White LED Applications

Abstract

We report the fabrication and optical/mechanical properties of perovskite/thermoplastic polyurethane (TPU)-based multicolor luminescent core−shell nanofibers and their large-scale fiber mats. One-step coaxial perovskite/TPU nanofibers had a high photoluminescence quantum yield value exceeding 23.3%, surpassing that of its uniaxial counterpart, due to the homogeneous distribution of perovskite nanoparticles (NPs) by the confinement of the TPU shell. The fabricated core−shell nanofibers exhibited a high mechanical endurance owing to the well elastic properties of TPU and maintained the luminescence intensity even under a 100% stretched state after 1000 stretching−relaxing cycles. By taking advantage of the hydrophobic nature of TPU, the ambient and moisture stability of the fabricated fibers were enhanced up to 1 month. Besides, large-area stretchable nanofibers with a dimension of 15 cm × 30 cm exhibiting various visible-light emission peaks were fabricated by changing the composition of perovskite NPs. Moreover, a large-scale luminescent and stretchable fiber mat was successfully fabricated by electrospinning. Furthermore, the white-light emission from the fabricated fibers and mats was achieved by incorporating orange-light-emitting poly[2-methoxy-5-(2-ethylhexyloxy)-1,4phenylenevinylene] into the TPU shell and coupling the turquoise blue-light-emitting perovskite NPs in the core site. Finally, the integrity of the perovskite-based TPU fibers was realized by fabricating a light-emitting diode (LED) device containing the orange-light-emitting fibers embedded in the polyfluorene emissive layer. This work demonstrated an effective way to prepare stable and stretchable luminous nanofibers and the integration of such nanofibers into LED devices, which could facilitate the future development of wearable electronic devices.

Nano–Micro Dimensional Structures of Fiber‐Shaped Luminous Halide Perovskite Composites for Photonic and Optoelectronic Applications

“…In this technique, insulating polymeric materials were used as matrix to encapsulate nanostructures or accompany conjugated polymers. Over the past 5 years, the polymer fiber matrixes have been successfully electrospun into HP based luminescent fibers, such as polyvinylpyrolidone (PVP), [ 101–104 ] polyacrylonitrile (PAN), [ 105,106 ] poly(methlymethacrylate) (PMMA), [ 107–109 ] polystyrene (PS), [ 110–114 ] polyvinyl alcohol (PVA), [ 112,115 ] polyvinyl acetate (PVAc), [ 114 ] polyurethane (PU), [ 116,117 ] styrene‐butadiene‐styrene (SBS), [ 118,119 ] and poly(vinylidene fluoride) (PVDF). [ 120,121 ] Since electrospinning requires chain entanglement and perovskite materials are not being able to electrospun without any matrix agent, polymer selection is crucially important concerning to solubility and spinnability.…”

“…Additionally, enhanced PLQY of nanofibers were achieved as a consequence of smaller nanocrystals since core flow rate was independently controlled in co‐axial nanofibers. [ 116 ]…”

“…[ 13,120 ] Elastomeric materials such as TPU, and SBS were demonstrated to encapsulate HP nanoparticles allowing stretchablity over 100% (up to 170% for SBS) without any mechanical and luminescent failure as indicated in Figure a. [ 116 ]…”

“…A prototype work on LED concept was proposed using electrospun nanofibers incorporated into the emissive layer to achieve color tunability in light emitting devices. [ 116 ] A blue emissive conjugated polymer, poly(9,9‐di‐n‐octylfluorenyl‐2,7‐diyl) (PFO) was used to fill the voids between NF systems in voltage driven LED device for overcoming poor interfacial contact between fibers and electrodes by smoother NF incorporated hybrid film‐electrode interface. [ 116 ] In this concept, white light emission was introduced via energy transfer between blue emissive layer and orange light emitting HP embedded TPU fibers.…”

“…Figures in the section of enhanced mechanical properties: Reproduced with permission. [ 116 ] Copyright 2019, American Chemical Society.…”