Robust Hydrophobic and Hydrophilic Polymer Fibers Sensitized by Inorganic and Hybrid Lead Halide Perovskite Nanocrystal Emitters

Abstract

Advances in the technology and processing of flexible optical materials have paved the way toward the integration of semiconductor emitters and polymers into functional light emitting fabrics. Lead halide perovskite nanocrystals appear as highly suitable optical sensitizers for such polymer fiber emitters due to their ease of fabrication, versatile solution-processing and highly efficient, tunable, and narrow emission across the visible spectrum. A beneficial byproduct of the nanocrystal incorporation into the polymer matrix is that it provides a facile and low-cost method to chemically and structurally stabilize the perovskite nanocrystals under ambient conditions. Herein, we demonstrate two types of robust fiber composites based on electrospun hydrophobic poly(methyl methacrylate) (PMMA) or hydrophilic polyvinylpyrrolidone (PVP) fibrous membranes sensitized by green-emitting all-inorganic CsPbBr 3 or hybrid organic-inorganic FAPbBr 3 nanocrystals. We perform a systematic investigation on the influence of the nanocrystal-polymer relative content on the structural and optical properties of the fiber nanocomposites and we find that within a wide content range, the nanocrystals retain their narrow and high quantum yield emission upon incorporation into the polymer fibers. Quenching of the radiative recombination at the higher/lower bound of the nanocrystal:polymer mass ratio probed is discussed in terms of nanocrystal clustering/ligand desorption due to dilution effects, respectively. The nanocomposite's optical stability over an extended exposure in air and upon immersion in water is also discussed. The studies confirm the demonstration of robust and bright polymer-fiber emitters with promising applications in backlighting for LCD displays and textile-based light emitting 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.…”

“…Besides, electrospun nanofibers were also used as a template of HP nanocrystals through electrospinning prior to post‐processes involving spin‐coating or immersing of nanofibers into the toluene solution of HP QDs to generate highly stable well‐distributed HP nanocrystals. [ 107 ]…”

“…Well dispersed nanocrystal domains with the dimension varying from around 10 nm to couple hundred nanometers, was reported not only for post‐synthesized spinning techniques but also one step methods without surfactant in the fiber geometry. [ 106,107 ] Elemental mapping techniques was used to reveal well distributed particles in nanoscale. [ 113 ] In macroscale perspective, widely used polymer based composite nanofiber systems showed homogenous distribution and emission evidenced by uniform luminesce of nanofiber morphology by confocal images.…”

“…To get a more insight into the QD concentration dependent properties of composite nanofibers, consisting of electrospun PVP/HP using the multi‐step approach, time resolved PL (TRPL) and PL spectroscopy was studied by Papagiorgis et al. [ 107 ] As indicated in Figure a,b, the linear increase in bandgap difference of samples up to 50 meV is observed as the concentration of nanocrystals increase from 0.05% to 5.0% Consequently, 100% of PLQY enhancement is exhibited while average PL lifetime decreases as shown in Figure 5c. Over a critical concentration (1%), an enhanced recombination rate was due to the increased exciton binding energy by dielectric screening.…”

Improving the Stability of CsPbBr3 Perovskite Nanocrystals by Peroxides Post-treatment

“…All inorganic cesium lead halide (CsPbX 3 , X = Cl, Br, and I) perovskite nanocrystals (NCs) are promising materials for optoelectronic applications Juang et al, 2019;Papagiorgis et al, 2019), especially for light emitting because of their optically tunable band gap and excellent photoluminescence quantum yields (PLQY). In spite of the excellent merits of the perovskite NCs in various fields, the applications of perovskite NCs are impeded by several issues with regard to their stability.…”