Structure and luminescence properties of CdSe/CdS-cellulose nanocomposites
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Structure and luminescence properties of CdSe/CdS‑cellulose nanocomposites S. R. Patra1 · B. Mallick2 Received: 8 April 2020 / Accepted: 7 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract We have observed the structure and luminescence properties of CdSe/CdS-cellulose nanocomposites (CCCNC) and characterized it. The CCCNC is composed of two component materials, nanocrystalline CdSe/CdS core–shell QDs and nanocrystalline cellulose. The structural and optical characteristics of CCCNC were analysed using XRD, TEM, PL and I–V characteristic techniques. A spherical phosphor particle of dimension about 14 nm was confirmed by TEM. The characteristic X-ray diffraction planes of the said QDs as (100), (002) and (101) were found out to be superimposed at the tail of the most intense plane (002) of cellulose. Sharp photoluminescence peak at 650 nm and absorption spectra indicate that the distributions of quantum size possess rigid structure of the entire shell. It is expected that the present study will have high promise for X-ray-induced photoluminescence-based sensing application.
1 Introduction Current improvement in the hot-injection (HI) synthesis of semiconductor-base nano-phosphor materials [1–3] has wide range of explorations covering the applications in photonics [4], opto-electronics [5] and bio-labelling [6], which provide a better understanding of nano-science in the domain of quantum confinement [2–7]. The HI synthesis of semiconductor nano-crystals can enable us to produce a desired crystalline phase. Synthesizing an epitaxial shell of an extensive band gap semiconductor approximately of the size of a nano-crystal core, which is generally a CdSe–CdS core–shell QDs, significantly improves the stability in photo-oxidation and enhances the photoluminescence quantum yield (PLQY) up to 80% [8–14]. Also, the PL polarization properties and alignment ability can be enhanced by controlling the shape of the nano-crystal [10–14]. Again, polymers are extensively used to coat and cover quantum dots (QDs) for synthesizing desired biocompatible QDs. Such materials are capable of providing good optical stability and, at the same time, polymers can carry ionic
or relative functional groups for the application of QDs. Mimosa pudica (MP) (a touch-sensitive plant) fibre is an electrically conducting sensing [15, 16] in nature. Because of its electro-active sensing and photo-conducting characteristics, it insists to think for the fabrication of scintillators and photon detectors in the X-ray regime [16]. In principle, in an X-ray image detector, an organic conducting polymer can substitute Se, which is an existing photoconductive substance that is used to produce fluorescent light in the visible range. Natural conducting polymer such as MP, which contains Se by default, is a good choice to design a windowless X-ray detector. Recently, research interests have emerged as to what QDs can be used for scintillation applications. Some early demonstrations of QD scintillators and their applicatio
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