Institut de ciencia de materials de Barcelona (ICMAB), Spain
Low-cost, stable and high performing organic
field effect-transistors (OFETs)
Organic radicals as promising building blocks
Date: 26th March 2019
Location: Room 108, J. Heyrovsky Inst. of Physical Chemistry, Prague
The abstract of the talk is attached. For those who want to meet the speaker individually, please contact martin.kalbacjh-inst.cas.cz. We are looking forward to meet you at the talk.
Title: Organic radicals as promising building blocks for electronics.
In recent decades, the robust molecular modification of surfaces has been a determining factor for progressing in the development of molecular electronic devices. Gold and more recently carbon based substrates decorated with functional small molecules have awakened much interest for sensing, biological, optoelectronic, molecular (spin)electronics, and catalytic applications, among others. Among other electroactive systems, we are especially interested in studying stable organic radicals (OR). In particular, perchlorinated triphenylmethyl (PTM) radicals which are chemically and thermally persistent redox and magnetically active species. These radicals have been deposited on surface (gold, ITO, sp2-carbon substrates) as nanometer thick films, self-assembled monoalyers and in single-molecule junctions. The charge transport measurements through PTM based films and at the single molecule level have elucidated the role of the unpaired electron and the molecule-electrode interface on the device performance. In addition, the electrochemical switchability on surface has been demonstrated leading to interesting memory functions. Finally, the covalent grafting on sp2-carbon substrates has permitted to fabricate highly sensitive enzyme-based electro-chemical sensors.
Title: Low-cost, stable and high performing organic field effect-transistors (OFETs)
Organic-based devices are attracting great attention for applications requiring low-cost and flexibility. Engineering processing techniques that could give rise to highly crystalline and homogenous semiconducting films resulting in reproducibly high mobility and reliable devices is a current challenge. We report here the bar-assisted meniscus shearing of organic semiconductor blends based on small semiconducting molecules and an insulating polymer. This technique results in highly crystalline thin films that show ideal OFET characteristics. Further, we investigated the influence of the deposition parameters and solution formulation on the thin film morphology and polymorphism, which in turn, has a crucial impact on the device performance. The best devices have also been successfully applied in water electrolyte gated OFETs exhibiting a very high performance and great potential for the development of sensors.