Joannis Kallitsis

Abstract:

Organic photovoltaic cells (OPVs) and polymeric light emitting diodes (PLEDs) are technologies where polymeric semiconductors are used providing a thin film, called the "active layer", which is responsible for the operation of the device. In the case of OPVs, polymer semiconducting electron donors are combined with electron acceptors, typically fullerenes or other carbon based nanostructures, forming a bicontinuous interpenetrating network. The efficiency of these so called Bulk Heterojunction (BHJ) OPVs is greatly dependant on the exact materials combinations as well as the morphology of the active layer. Our efforts were devoted on the scale up synthesis of the different efficient polymeric electron donors as well as their application on printable OPV devices thereof. Also control and stabilization of the active layer�s blend morphology was attempted through the incorporation of a third component acting as compatiblizer and/or stabilizer. Thus, employment of hybrid polymer-fullerene [1,2] additives, comprising the electron donating polymer and the fullerenic electron acceptor part was used in order to enhance the stability of the active blend. In the case of PLEDs, both semiconducting polymers and polymeric metallocomplexes [3] are used in order to obtain the desired colored emission. Working in this direction, polymeric materials with controlled light emission have been synthesized and used for PLEDS device construction and testing [4]. Moreover, we also combined different chromophore bearing light emitting polymers and copolymers with Iridium (Ir) based polymeric metallocomplexes in different ratios in order to effectively control the final light emission. Depending on the well-defined copolymers� composition and even using polymer blends, the optoelectronic properties of the final active materials were modulated leading to the fine tuning of the light emission properties of the final materials and devices. ACKNOWLEDGEMENTS: This research has been co-financed by the project SMARTONICS � 310229 - FP7-NMP-2012.1.4-1 (2013-2017) �Development of Smart Machines, Tools and Processes for the Precision Synthesis of Nanomaterials with Tailored Properties for Organic Electronics� and by the project "Green/k Sustainable Lighting - GR-Light" 11SYN-5-573, GSRT-Greece. References [1] S. Kakogianni, S. N. Kourkouli, A. K. Andreopoulou, J. K. Kallitsis, J. Mater. Chem A, 2, 8110-8117 (2014) [2] S. Kakogianni, M. A. Lebedeva, G. Paloumbis, A. K. Andreopoulou, K. Porfyrakis, J. K. Kallitsis, RSC Adv, 6, 98306 � 98316 (2016) [3] E. K. Pefkianakis, N. P. Tzanetos, J. K. Kallitsis, Chem. Mater., 20, 6254�6262 (2008) [4] M. Gioti, D. Kokkinos, C. I. Chaidou, A. Laskarakis, A. K. Andreopoulou, J. K. Kallitsis, S. Logothetidis, Phys. Status Solidi A, 213, 2947-2953 (2016).