AFM 2022: The 4th Conference on Advanced Functional Materials      29-31 August

Professor Katan's web page

Title TBA.

Professor Facchetti's web page

Unconventional film morphologies for stretchable electrochemical transistors

¹ Northwestern University 2145 Sheridan Road, Evanston IL, 60208 USA 
*Email: a-facchetti@northwestern.edu

Abstract

The realization of fully stretchable electronic materials is central to advancing new types of mechanically agile and skin-integrable optoelectronic device technologies. In this presentation we report a materials design concept combining a porous organic semiconductor honeycomb film morphology with a biaxially pre-stretched platform that enables high-performance organic electrochemical transistors (OECTs) with charge transport stability up to 30-140% tensional strain, limited only by metal contact fatigue. The pre-stretched honeycomb channel semiconductor, donor-acceptor polymer DPP-g2T (DPP=diketopyrrolopyrrole, 2T=dithiophene), exhibits high ion uptake with ultra-stable electrochemical and mechanical properties, > 1500 redox cycles with 10000 stretching cycles under 30% strain. Highly reliable electrocardiogram recording cycles and synapse responses under varying strains, along with mechanical finite element analysis, underscore that the present stretchable OECT design strategy is suitable for diverse applications requiring stable signal output under deformation with low power dissipation and robustness to mechanical deformation.

Reference

<sub>1. Chen, J.; Huang, W.; Zheng, D.; Xie, Z.; Zhuang, X.; Zhao, D.; Chen, Y.; Su, N.; Chen, H.; Pankow, R. M.; Gao, Z.; Yu, J. Guo, X.; Cheng, Y.; Strzalka, J.; Yu, X.; Marks, T. J.; Facchetti, A. Highly-Stretchable Organic Electrochemical Transistors with Strain-Resistant Performance Nature. Mater. 2022, 21, 564–571.
2. Huang, L.; Wang, Z.; Chen, J.; Wang, B.; Chen, Y.; Huang, W.; Chi, L.; Marks, T. J.; Facchetti, A. Porous Semiconducting Polymers Enable High-Performance Electrochemical Transistors. Adv. Mater. (Weinheim, Ger.) 2021, 33(14), 2007041.</sub>

Author introduction

Professor Bilek's web page

Title TBA

Professor Ramanath's web page

Molecular-design of inorganic interfaces and nanomaterials

Professor Schubert's web page

Title TBA

Professor Furo's web page

NMR Spectroscopic Approaches to Materials. A Case Study in Batteries and Supercapacitors

_{István Furó and Sergey V. Dvinskikh
Department of Chemistry, KTH Royal Institute of Technology, Stockholm, Sweden}
Contact: furo@kth.se, sergeid@kth.se

Last year, the Swedish Research Council VR granted a new national infrastructure SwedNMR. Distributed over nine Swedish universities, the network is tasked by facilitating and broadening access to NMR spectroscopy. One of the three access nodes (located jointly at Stockholm University and KTH Royal Institute of Technology) handles applications of NMR to materials while the other nodes concern biomolecular and medical applications such NMR-based metabolomics. 

Arguably, NMR in materials is an extremely heterogeneous area and, perhaps by tradition, material scientists are not the most ardent users of this methodology. In this lecture we wish to highlight the ways the rich variety of NMR-based experiments can be applied to materials. We shall also illustrate the potential and comparative advantage with NMR that can be realized despite its disadvantages (among other things, its low signal strength and its interpretational pitfalls primarily connected to its tendency to make structural information dependent on the dynamical regime).

Our illustrative examples are going to be taken from the family of materials that, when combined into devices like batteries and supercapacitors, permit us to store electric energy. We shall emphasize that in battery and supercapacitor materials NMR approaches adapted to either the electrodes or the electrolyte can provide direct and local structural and dynamical information about the most crucial component in those systems: the ions. As we are also going to show, a lot what can be learned from NMR is not accessible by other methods. In an orthogonal manner, we shall also try to illustrate what possible insights can be gained from different sorts of NMR parameters like chemical shifts and line splittings (chemical/electronic environments and mesoscopic structures), spin relaxation times (local dynamics), self-diffusion and electrokinetic coefficients (long range dynamics of molecules and ions) and, on a distinct manner, by NMR (or, MRI) images.

Professor Heintz's web page

Title TBA