Synthetic Metals 159 (2009) 1014–1018 Contents lists available at ScienceDirect Synthetic Metals journal homepage: www.elsevier.com/locate/synmet Phenoxazine and N-phenyl-1-naphtylamine-based enamines as hole-transporting glass-forming materials R. Paspirgelyte a , J.V. Grazulevicius a,∗ , S. Grigalevicius a,∗ , V. Jankauskas b a Department of Organic Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254, Kaunas, Lithuania b Department of Solid State Electronics, Vilnius University, Sauletekio Aleja 9, LT10222, Vilnius, Lithuania article info Article history: Received 1 November 2008 Received in revised form 20 December 2008 Accepted 12 January 2009 Available online 6 February 2009 Keywords: Electro-active material Enamine Hole drift mobility Ionization potential abstract New aromatic enamines were synthesized by condensation of the commercially available phenoxazine and N-phenyl-1-naphtylamine with 2,2-diphenylacetaldehyde or 2-phenylpropionaldehyde. The materi- als were examined by various techniques including differential scanning calorimetry, UV and fluorescence spectrometry, electron photoemission and time of flight techniques. The electron photoemission spectra of the layers of the amorphous materials showed the ionization potentials of 5.42–5.61eV. Hole drift mobilities in the layers of 33–50% solid solutions of the derivatives in bisphenol Z polycarbonate range from 10 -5 to 3.4 × 10 -4 cm 2 /V s at high electric fields. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Low-molar-mass organic compounds that readily form stable glasses receive growing attention both in terms of academic inter- est and technological applications [1–3]. Some of these derivatives belong to the classes of organic electro-active materials and are known for various applications such as organic light-emitting diodes, photovoltaic cells, electro-photographic photoreceptors [4–7]. Among organic semiconductors materials transporting positive charges are so far much wider synthesized, studied and applied. For various fields of application the hole-transporting materials with the certain complex of properties are required. No reliable theo- ries for the design of organic semiconductors having an optimal combination of the required properties have yet been developed. Consequently, such materials need to be discovered experimen- tally. Different electrophores are used in the design and synthesis of organic hole-transporting compounds. In this work, we have designed and synthesised new electro-active materials having phe- noxazine and N-phenyl-1-naphtylamine fragments. These building blocs were used for the preparation of aromatic enamines. The materials demonstrate promising optoelectronic properties, how- ever their synthesis and properties are little studied [8,9]. ∗ Corresponding author. E-mail addresses: juozas.grazulevicius@ktu.lt (J.V. Grazulevicius), saulius.grigalevicius@ktu.lt (S. Grigalevicius). 2. Experimental 2.1. Instrumentation 1 H NMR spectra were recorded using Varian Unity Inova (300 MHz) apparatus. Mass spectra were obtained on a Waters ZQ 2000 spectrometer. FT-IR spectra were recorded using PerkinElmer FT-IR system. UV spectra were measured with a Spectronic Genesys TM 8 spectrometer. Fluorescence (FL) spectra were recorded with a Hitachi MPF-4 spectrometer. Differential scanning calorimetry (DSC) measurements were carried out using a Bruker Reflex II thermo-system. Thermogravi- metric analysis (TGA) was performed on a Netzsch STA 409. The TGA and DSC curves were recorded in a nitrogen atmosphere at a heating rate of 10 ◦ C/min. The ionization potentials of the layers of the compounds syn- thesized were measured by the electron photoemission method in air, which was described earlier [10]. The measurement method was, in principle, similar to that demonstrated by Miyamoto et al. [11]. The samples for the ionisation potential measurement were prepared as reported previously [12]. The materials were dissolved in THF and were coated on Al plates pre-coated with ∼0.5 m thick methylmethacrylate and methacrylic acid copolymer (MKM) adhesive layer. The function of this layer was not only to improve adhesion, but also to eliminate the electron photoemission from Al layer. In addition, the MKM layer is conductive enough to avoid charge accumulation on it during the measurements. The thickness of the layers was 0.5–1 m. 0379-6779/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.synthmet.2009.01.015