Synthetic Metals 209 (2015) 29–33 Contents lists available at ScienceDirect Synthetic Metals jo ur nal home p age: www.elsevier.com/locate/synmet Thermal behaviour and thin ﬁlm properties of a bis-pyrene compound for organic thin ﬁlm transistor applications Catalin Constantinescu a,b,∗ , Abdou Karim Diallo c , Anthony D’Aleo c , Frédéric Fages c , Petre Rotaru d , Christine Videlot-Ackermann c , Philippe Delaporte a , Anne-Patricia Alloncle a a Aix-Marseille Université/CNRS, LP3 (UMR 7341), F-13288 Marseille, France b INFLPR – National Institute for Laser, Plasma and Radiation Physics, RO-077125 Magurele, Romania c Aix-Marseille Université/CNRS, CINaM (UMR 7325), F-13288 Marseille, France d University of Craiova, Department of Physics, RO-200585 Craiova, Romania a r t i c l e i n f o Article history: Received 31 March 2015 Received in revised form 11 June 2015 Accepted 18 June 2015 Keywords: Chemical synthesis Thermal analysis Thin ﬁlm Semiconductor Organic thin ﬁlm transistor a b s t r a c t Following the standard Sonogashira cross-coupling conditions, the reaction between 1,4-diiodo-2,5- bis(octyloxy)benzene with 2.2 equiv. of 1-ethynylpyrene afforded a yellowish bis-pyrene derivative, namely 1,4-bis(octyloxy)-2,5-bis(ethynylpyrene)benzene, that exhibits typical ﬂuorescence and semiconducting properties. Thermal analysis studies are discussed, with emphasis made on the oxidative decomposi- tion and thermal effects. Further on, thin ﬁlms have been grown by vacuum thermal evaporation, on silicon and quartz substrates. The temperature’s inﬂuence on the thin ﬁlm’s morphology and electrical properties is investigated. Finally, top-contact thin ﬁlm transistor conﬁgurations are presented and the inﬂuence of substrate temperature is discussed with respect to the semiconducting properties. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Pyrene is the smallest peri-fused polycyclic aromatic hydrocar- bon [1] and, together with most of its natural derivatives, it occurs in oil, coal, and tar deposits. Such compounds also occur as ther- mal degradation by-products in smoke and in the residue from fuel burning, through incomplete combustion, and are know to exist in cooked foods [2]. Spectroscopic data and models prove that inter- stellar medium and some celestial bodies may also contain large amounts of pyrene and its derivatives [3–5], and it is largely con- sidered that such compounds act as basic bricks for the earliest forms of life [6]. Most of pyrene compounds and derivatives are used in dyes and dye precursors [7]. Similar to other polycyclic aromatic hydrocarbons, such as anthracene, tetracene, pentacene, and other superior acenes (or polyacenes), pyrene exhibits strong – interactions [7–9]. Thus, pyrene and its derivatives are also ∗ Corresponding author at: Aix-Marseille Université/CNRS, LP3 (UMR 7341), F- 13288 Marseille, France. Tel.: +33 605814937; fax: +33 491829289. E-mail addresses: catalin.constantinescu@inﬂpr.ro, constantinescu@lp3.univ-mrs.fr (C. Constantinescu), videlot@cinam.univ-mrs.fr (C. Videlot-Ackermann), alloncle@lp3.univ-mrs.fr (A.-P. Alloncle). valuable molecular probes via ﬂuorescence spectroscopy [9–12], organic electronics, photovoltaics and in optoelectronic applica- tions [7,13–16], and are actively researched in chemistry and electrical engineering [16–19]. In this paper, we present results on the synthesis procedure and thermal behaviour of a pyrene-based compound, namely 1,4- bis(octyloxy)-2,5-bis(ethynylpyrene)benzene, further referred to as bis-pyrene. Besides typical ﬂuorescence capabilities, with use as a molecular probe via ﬂuorescence spectroscopy (a dedicated discussion on this topic is available in Ref. [11]), the compound also exhibits semiconducting properties. Organic thin ﬁlm transis- tor (OTFT) studies are presented, with respect to the temperature’s inﬂuence during thin ﬁlm growth. 2. Experimental 2.1. Materials and synthesis The synthesis of the bis-pyrene compound was carried out by reacting 1,4-diiodo-2,5-bis(octyloxy)benzene with 2.2 equiv. of 1- ethynylpyrene [20,21], as presented in Scheme 1, following the standard Sonogashira cross coupling conditions [22]. All solvents used for synthesis were of synthesis grade. http://dx.doi.org/10.1016/j.synthmet.2015.06.019 0379-6779/© 2015 Elsevier B.V. All rights reserved.