Volume 8 • Issue 4 • 1000355 J Chem Eng Process Technol, an open access journal ISSN: 2157-7048 Research Article Idzik et al., J Chem Eng Process Technol 2017, 8:4 DOI: 10.4172/2157-7048.1000355 Research Article Open Access Journal of Chemical Engineering & Process Technology J o u r n a l o f C h e m i c a l E n g i n e e r i n g & P r o c e s s T e c h n o l o g y ISSN: 2157-7048 *Corresponding authors: Krzysztof R Idzik, Department of Applied Geology, Georg-August University of Göttingen, Goldschmidtstr, Göttingen, Germany, Tel: +495513912861; E-mail: krzysztof.idzik@pwr.wroc.pl Simone Techert, Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany, Tel: +495512011268; E-mail: stecher@gwdg.de Received September 27, 2017; Accepted October 07, 2017; Published October 15, 2017 Citation: Idzik KR, Cywiński PJ, Kuznik W, Glaser L, Techert S (2017) Optical Properties and Quantum-Chemical Calculations of Various Bithienyl Derivatives of Benzene, Triazine and Triphenyltriazine as Organic Light Emitting Diodes. J Chem Eng Process Technol 8: 355. doi: 10.4172/2157-7048.1000355 Copyright: © 2017 Idzik KR et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Optical Properties and Quantum-Chemical Calculations of Various Bithienyl Derivatives of Benzene, Triazine and Triphenyltriazine as Organic Light Emitting Diodes Krzysztof R Idzik 1,2,3 *, Piotr J Cywiński 4 , Wojciech Kuznik 5 , Leif Glaser 2 and Simone Techert 2,3,6 1 Department of Applied Geology, Georg-August University of Göttingen, Goldschmidtstr. 1, 37077 Göttingen, Germany 2 Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany 3 Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany 4 Functional Materials and Devices, Fraunhofer Institute for Applied Polymer Research, Geiselbergstr. 69, 14476 Potsdam-Golm, Germany 5 Department of Electrical Engineering, Czestochowa University of Technology, Armii Krajowej 1742-201 Czestochowa, Poland 6 Institute of X-Ray Physics, Georg-August Universität, Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany Abstract Derivatives of tris (2,2-bithiophen-5-yl) derivatives based on a benzene, a triazine or a triphenyltriazine core are presented for optical light emitting diode functionality. Optical properties as well as their corresponding molecular energy levels were investigated by UV-VIS absorption supported by fuorescence spectra. Furthermore, DFT and TDDFT calculations for obtained materials are presented to supplement the experimental data. It is demonstrated that HOMO - LUMO orbitals are delocalized uniformly on aromatic core and bithienyl substituents. Additionally, an OLED was built using synthesized compounds to facilitate electron transport and act as light emitting layer. Optical and charge transport properties along with good electrochemical stability confrm potential application of bithiophene- aromatic hybrids in electrochromic devices, light emitting electrochemical cells and spintronics. Keywords: Bithiophene; Fluorescence spectroscopy; DFT calculations; TDDFT simulations; OLED Introduction Symmetrical starting materials are useful building blocks for designing complex target molecules. Te structural symmetry can be used to reduce the number of steps necessary for the synthesis of a target molecule. Symmetrical molecules are also ofen used as central cores in various oligomers [1]. Organic π-conjugated structures containing thiophene units play an important role in the search for new materials and their novel applications such as organic solar cells [2,3] or organic feld efect transistors [4]. In this case, the interest in thiophenes is associated with high hole mobility. Tiophenes with well-defned chemical structures have recently attracted great attention not only as an example of model compounds for conducting materials, but also as a new class of functional π-electron systems [5-11]. Branched oligothiophenes based on central phenyl core have come to the fore over the last several years, acting both as monomers in cross-linked semiconducting polymers [12-15] and as components of conjugated dendrimers [16-18]. Some of the 2,4,6-trisubstituted-1,3,5-triazine derivatives exhibit properties characteristic for liquid crystalline materials and fnd applications in coordination chemistry and crystal engineering [19-22]. On the other hand, star-shaped systems possessing donor–acceptor intramolecular arrangement can exhibit strong internal charge transfer band at low energy levels and therefore, have found applications in organic solar cells [23]. Over the last decade, highly efcient blue OLEDs have attracted considerable attention due to their potential applications in full color ultra-thin fat panel displays [24-30]. Organic light sources are currently made from either low molecular weight organic materials or polymers. For the former, the layer structure of the OLED is usually deposited on a rigid base made from glass or metal [31-34]. In the current work a series of planar donor–acceptor systems based on an electron-withdrawing triazine core substituted at the 2,4 and 6 positions with various electron-donating bithiophene branches are presented. Te optical, structural and functuional properties of these systems are compared to a series of symmetric molecules based on benzene and triphenyltriazine core. Tey are connected to bithiophene units and derivatives containing triazine core. For a systematic study and rational of OLED functionality UV-Vis, steady-state and time-resolved fuorescence spectroscopy have been performed. Te studies are supported DFT calculations and TDDFT simulations. Finally functionalizing studies of an OLED device using synthesized low molecular weight material as electron transport with the new compounds as light emitting layers are summarized. All compounds studied in this work were obtained by the Stille cross-coupling methodology according to the procedure reported in our previous work [35]. Results and Discussion Optical measurements Optical studies reveal valence electron transition in the visible and UV regime. All reported bithiophene derivatives were studied using UV-VIS spectroscopy. Electronic absorption spectra collected for bithiophene derivatives in chloroform are presented in Figure