Preparation Of Chiral Helical Polyacetylene-based Circularly Polarized Luminescence Nanofibers And Their Properties

Chrial mateirals with circularly polarized luminescence(CPL)are becoming a hot research topic in chiral and luminescent related material areas in recent years,because of their significant potential applications in 3D displays,optical encryption,data storage and asymmetric photocatalysis.Up to now,most of the research on CPL is limited to solution systems,but solid-state luminescent materials have more potential practical applications in fabricating thin film devices.Considering the importance of solid-state CPL materials,we,in this study,developed a strategy for constructing CPL-active nanofibers by electrospinning technology,from which full-color tunable and white CPL-active nanofibers were prepared.The results demonstrate the universality of the strategy established in the present study for constructing CPL nanofibers.Besides,taking advantage of flexible morphological adjustment and high-throughput continuous production of electrospinning technology,this work provides unprecedented opportunities for large-scale preparation of micro-and nano-materials with excellent CPL properties.Perovskite has emerged as a super star in various research fields including solar cells,light-emitting diodes,and photodetectors,due to the excellent optoelectronic properties.Chirality can be introduced to perovskite to realize CPL-active perovskite with excellent photoelectric properties,which has received ever-increasing attention.Nowadays,CPL-active perovskites are usually prepared by three approaches,i.e.,direct synthesis with chiral organic molecules,post-modification through surface interactions,and self-assembly with chiral supramolecules.The CPL-active nanofibers in the present stuy are prepared through a one-step electrospinning strategy,in which chiral helical polyacetylene,perovskite nanocrystals and polyacrylonitrile serve as chiral source,fluorescent source and electrospinning matrix,respectively.The major contents are as follows:1.The CPL-active chiral polymer/perovskite hybrid nanofibers are prepared by electrospinning strategy,in which chiral helical polyacetylene acts as a chiral filter to realize highly efficient CPL emission without any covalent bond or noncovalent interactions between chiral and fluorescent components.We in this study establishes a convenient and universal stratagy for preparing chiral spiral polymer/perovskite materials with excellent CPL emission;and it is the first attempt to combine perovskite with chiral polymer for generating CPL emissions.Specially,perovskite nanocrystals are in situ formed during the electrospinning process,which avoids the tedious process for preparing and purifying perovskites.The prepared hybrid nanofibers all exhibit good long-time stability in air,owing to the effective protection effect of polymer matrix.Moreover,the generation mechanism is proposed through the investigation of CD and CPL spectra in combination with the side-by-side CPL test results.2.Full-color tunable CPL nanofibers are prepared by adjusting the type of fluorophores,in which chiral helical polyacetylene is used as a circular polarization filter.CPL can be generated taking advantage of emission and CD effects with suitable wavelength range,in spite of neither covalent bond nor non-covalent interactions between the fluorescence component and chiral source.CPL nanofibers with white emission are further prepared by coaxial electrospinning strategy to control the energy transfer efficiency,in which white emission is achieved by separating the donor and acceptor fluorescein separately into core and shell architectures.Finally,with the prepared white CPL nanofiber fims in hand,we further explore their application in circularly polarized organic light emitting device(CPOLED),indicating the promising application in the field of three-dimensional displays and optoelectronic devices.