Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-019-01473-z Microwave‑assisted synthesis of Fe x Zn 1−x O nanoparticles for use in MEH‑PPV nanocomposites and their application in polymer light‑emitting diodes Thaiskang Jamatia 1  · David Skoda 1  · Pavel Urbanek 1  · Jakub Sevcik 1  · Jan Maslik 1  · Lukas Munster 1  · Lukas Kalina 2  · Ivo Kuritka 1 Received: 3 December 2018 / Accepted: 6 May 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract A one-step microwave-assisted polyol method was used to fabricate Fe x Zn 1−x O (x = 0.01, 0.05, 0.10) nanoparticles. Zinc acetate dihydrate, iron (III) acetylacetonate, oleic acid and diethylene glycol were placed in a Tefon-lined reaction vessel. The reaction mixture was heated up to 250 °C for 15 min in a microwave reactor. The surface modifcation with oleic acid prevented agglomeration of the nanoparticles. The X-ray difraction analysis revealed characteristics wurtzite hexagonal structure of ZnO and successful incorporation of the Fe dopant into the host crystal lattice. Doping of ZnO by Fe led to bandgap modifcation as estimated by Tauc plot. The as-prepared nanopowders were dispersed in toluene and mixed with a poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) polymer to make stable homogenous dispersions. Then, the Fe x Zn 1−x O/MEH-PPV nanocomposite thin flms were prepared by spin coating and used as thin active layers in polymer light-emitting diodes. The thickness of deposited Fe x Zn 1−x O/MEH-PPV flm was ca. 30 nm and that of reference neat MEH-PPV flm was ca. 25 nm. The electroluminescent spectroscopy study showed that direct blending of MEH-PPV with Fe-doped ZnO nanoparticles is a simple and efective approach to signifcantly increase the luminance intensity of the diode in comparison to the diode fabricated by neat MEH-PPV. 1 Introduction The importance of zinc oxide semiconductor nanoparticles has attracted a lot of researchers due to its wide direct band- gap (3.37 eV) and large exciton binding energy at room tem- perature (60 meV). In addition, the introduction of impurity atoms into the ZnO crystal structure modifes the optical and electrical properties of the semiconductor. Notably, ZnO semiconductor nanoparticles doped with transition metals (TM) like V, Cr, Mn, Fe, Co, Ni, Cu etc., have been reported many times in the literature [1–7]. Further, TM-doped ZnO nanoparticles offer many applications in optoelectronic devices [8], solar cells [9], gas sensors [10], diluted mag- netic semiconductors [11], etc. The doping of the TM ions into the ZnO lattice is made possible because of the thermal and chemical stability of ZnO nanocrystals. Likewise, the room temperature stability of excitons of ZnO is a result of large excitonic binding energy rendering the electronic devices to function at low threshold voltages [12]. Several techniques have been employed to synthesise TM-doped ZnO nanocrystals such as combustion method [13], sol–gel [11], co-precipitation [14] etc. Fe-doped Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10854-019-01473-z) contains supplementary material, which is available to authorized users. * David Skoda dskoda@utb.cz Thaiskang Jamatia jamatia@utb.cz Pavel Urbanek urbanek@utb.cz Jakub Sevcik j4sevcik@utb.cz Lukas Munster munster@utb.cz Lukas Kalina kalina@fch.vut.cz Ivo Kuritka kuritka@utb.cz 1 Centre of Polymer Systems, Tomas Bata University in Zlin, Tr. Tomase Bati 5678, 76001 Zlin, Czech Republic 2 Materials Research Centre, Brno University of Technology, Purkyňova 464/118, 61200 Brno, Czech Republic