MultiscAle STructure/propERty relationship in MIxed (ionic/electronic) (macro)molecular coNDuctors: Towards new generation organic bioelectronics devices. – MASTERMIND

MASTERMIND is an exploratory (TRL 1-3) collaborative research project (PRC) aiming at: i) establishing structure-property relationships in new generations of organic mixed ionic-electronic conductors (OMIECs) and ii) optimizing (ion-electron) electrochemical transduction by comparing experimental and theoretical resulting from the characterization of organic electrochemical transistors (OECTs) to perform proof of concept validations of the cutting edge strategies implemented. To make a major quantitative leap with respect to the state-of-the-art, the scientific approaches & methodology deployed aim at producing a figure of merit (FoM) for OECTs, i.e. an µOECT.C* product, greater than 1000 F/cm/V/s.

Commercially available, the PEDOT:PSS composite material is currently the archetype of active layers for OECTs. Although easy to access, this family of OMIECs does not allow a tailoring of the structural organization on the multi-scale continuum (nano->micro/macroscopic scales) required to significantly improve the performance of OECTs. To overcome this, a successful strategy pursued by some researchers has emerged over the past 5 years: Developing the engineering and synthesis of OMIECs 2.0 consisting of comb-shaped architectures in which the pi-conjugated skeleton providing the electronic conduction (e-/h+) is decorated by pendant chains (e.g. of oligo(ether) type) ensuring ionic conduction. The first successes achieved to date validating its disruptive potential can be rationalized by a better control of nano/micro-phase segregation (ionic/electronic) processes within OMIECs materializing in the increased performances in OECTs configuration. As part of this paradigm shift, MASTERMIND aims to amplify this generic approach through OMIECs consisting of molecular model materials (M2Cs) to their macromolecular analogues (M3Cs). To reach the targeted performances, an unprecedented to date combination of strategies to optimize the respective size of the electronic and ionic domains and to increase the electronic and ionic mobilities via specific doping of the pi-conjugated backbone and ionically conductive side- or linear-chains will be implemented. A double originality thus characterizes the program of MASTERMIND: i) the engineering and synthesis of OMIECs with a (p and n-type) pi-conjugated backbone with oligo(carbonate) side-or linear-chains whose electronic and ionic mobilities will be adjusted by electronic (p and n-type dopants) and ionic (lithium salts) doping, respectively and ii) mastering the multi-scale structuration of electronic and ionic domains by the combination of bottom-up (i.e. self-organization by (apolar/polar) nanophase segregation in 1D and 2D morphologies: nano->mesoscopic scale) and top-down (i.e. by micro/nanoimprint lithography: macro/micro->mesoscopic scale) approaches. The comparison of the experimental results obtained in OECT configurations relying on OMIECs with optimized structural organization and charge carrier mobility with the physical modeling of their behaviors will act as a feedback loop allowing the emergence of true OMIEC substitutes to PEDOT:PSS.

The consortium of laboratories, united for the first time in MASTERMIND, combines the complementary expertise of 3 partners internationally recognized in organic (bio)electronics that is fully in line with the themes supported by the CES06 scientific committee. MASTERMIND will benefit from an ad hoc "Chemistry-Materials-Devices-Modeling" value-chain ensuring the continuum of complementary skills required to achieve its objectives. Benefiting from ANR budget of k€ 472.2, this PRC project will involve 69.5 pm of permanent researchers and 96 pm of non-permanent researcher, i.e. a cumulative 3.94 full-time researchers over 42 months. The scientific spin-offs of MASTERMIND will be exploited (patents, publications) to ensure a technological transfer (start-up) towards breakthrough innovations for a better interfacing of the living world with electronics.