Séminaire LMGP - 04/07/2017 - SANNICOLO Thomas

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PhD Student, Thomas SANNICOLO
Univ. Grenoble Alpes, CEA, Liten, CNRS, Grenoble INP, LMGP

Abstract

Among emerging transparent electrodes (TEs), silver nanowire (AgNW) networks appear as a promising substitute to indium tin oxide (ITO) since these percolating networks exhibit high flexibility and excellent optoelectronic properties, with sheet resistance of a few Ω/sq and optical transparency of 90%, fulfilling the requirements for many applications such as solar cells, OLED displays, transparent heaters, or radio-frequency (RF) antennas and transparent shielding.

In-situ electrical measurements performed during optimisation process such as thermal annealing and/or chemical treatments provide useful information regarding the activation process of the junctions. Besides, nano-characterisation techniques such as Transmission Electron Microscopy (TEM) and Ultramicrotomy help visualizing the physical phenomena involved in the diffusion of silver atoms to create well-sintered junctions. At the network’s scale, our ability to distinguish the nanowires taking part in the electrical conduction from the inactive nanowires is a critical issue for the applications. A discrete activation process of efficient percolating pathways through the network was evidenced: in the case where the network density is close to the percolation threshold and when low voltage is applied, individual “illuminated” pathways can be detected through the network while new branches get activated as soon as the voltage is increased. More generally, the electrical distribution in AgNW networks is highly dependent on the density of deposited nanowires and on the optimization treatments.

In this seminar, we will present our results on the study of AgNW networks at the macro and nano scales described above and will correlate it with the overall performance/characteristics of the networks. We will also present results on the integration of optimized AgNW networks into functional devices.