Generic approach to new organic semiconductors for electronic applications – GATE

Organic electronics is the next ubiquitous platform for the electronics revolution, with devices such as organic light-emitting diodes, which are already entering the market, and many other applications are being envisioned such as, foldable displays, e-paper or radio frequency identification tags, (RFID). Among attractive features of organic electronics are: large-area coverage of devices, lightweight, flexible devices, simple processing of diverse materials, reduced material wastage, low fabrication cost and single patterned deposition techniques. All these devices involve charge transport as the main process in their operation. Organic semiconductors (OSs) that meet the criteria of high mobility, easy processability and better stability are needed. To achieve these requirements and to push OSs to the next level, a new concept for molecular design and a deeper understanding of the structure-property relationships are required. GATE proposes to explore several key design strategies to develop a versatile synthetic approach to generate library of p-conjugated OSs, with on-demand properties combining high charge carrier mobility, easy processability and better stability by incorporating aromatic and antiaromatic subunits, assembled in Lego style by fusing them in desired sequence. This will lead to expand the library of molecular building blocks beyond the current state of the art. The concept of aromaticity is of fundamental importance in designing and synthetizing of novel organic materials and also for classifying their physical and chemical properties. The degree of the stability, and the overall properties of the materials, including electronic structures, physical properties, and chemical reactivity, is a delicate balance between aromatic and non-aromatic subunits and their annelation modes. These materials are: a) Stable low bandgap Polycyclic aromatic hydrocarbons (PAHs) based on bisacenes; b) Ambipolar and n-type quinoïdal polycyclic molecules (QPHs) with closed or open shell structures based on indenoacene and zethrene derivatives.
The originality of GATE relies in developing a multidisciplinary approach, from molecules to functional electronic devices, OFETs and photovoltaic cells, that combines:
i) molecular design, synthesis and development of versatile synthetic strategy to access library of OSs beyond the current state of the art, integrating easy processability, stability and high mobility of charges, ii) self-assembly driven by crystal engineering to produce solution-processed OFET materials, all these allow for precise control over device performance, OTFTs and solar cells. The focus of the GATE project will be to gain fundamental understanding of, molecular self-assembly, relationships linking (supra)molecular structure and property through optical, electrochemical, thermal, microstructural (both single-crystal and thin-film), and electrical measurements and of the correlation exiting between structural parameters at various length scales and electronic, optical and charge transport properties. Special efforts will be made to fabricate OFETs and photovoltaic devices to use them as characterization platforms for studying their OFET and OPV properties and performance of selected new organic semiconductors developed for the GATE project.