New publications

R. Bahariqushchi, S. Cosentino, M. Scuderi, E. Dumons, L. P. Tran-Huu-Hue, V. Strano, D. Grandjean, P. Lievens, G. Poulin-Vittrant, C. Spinella, A. Terrasi, G. Franzò, S. Mirabella, Free carrier enhanced depletion in ZnO nanorods decorated with bimetallic AuPt Nanoclusters, Nanoscale 12 (2020) 19213-19222.

Click here to read.

A way to harvest mechanical energy: Flexible Piezolelectric Nanogenerators

In the GREMAN laboratory, conducting extended work on zinc oxide (ZnO) nanowire generators, a recently completed PhD thesis sheds light on a potential industrialized production of these nanowires. In the framework of the Energy for Smart Objects (EnSO) European project, Camille Justeau worked on a low-cost manufacturing process of a ZnO nanowire-based nanogenerator, an energy transducer capable of converting mechanical energy into electricity. This new type of transducer, once associated with devices capable of storing energy (a micro-battery for example), will form an Autonomous Energy Micro-Source (AMES).

The ZnO nanowires were obtained using a low-temperature (<100°C) chemical process, called hydrothermal synthesis. ZnO is used for its piezoelectric capacities (the property of materials to polarize and produce electricity when bended or compressed) and its semi-conductor properties. Under precise conditions, a chemical reaction allows to grow on a substrate a “carpet” of millions of aligned nanowires, about 1 micrometer long, with excellent crystalline properties. Once the reaction is ended, the ZnO formation on the substrate is covered by polymer layers, including a protection polymer that makes the nanogenerator flexible while protecting it from any damage. Once pressure is applied on the nanogenerator, the nanowires inside are compressed and produce an electric potential, which supplies an external electrical circuit.

Once this device is advanced enough, the nanogenerator will be capable of supplying low power sensors in direct contact with a moving body, a natural (water flow, a heartbeat…) or an industrial (a moving machine or vehicle) energy source. The concept, capable to adjust to specific user needs, opens up a vast field of possible applications that are yet to be discovered.

Read more:

C. Justeau, T. Slimani Tlemcani, G. Poulin-Vittrant, K. Nadaud, D. Alquier, A comparative study on the effects of Au, ZnO and AZO seed layers on the performance of ZnO nanowire-based piezoelectric nanogenerators, Materials 12 (2019) 2511. Click here for more details.

K. Nadaud, G. Poulin-Vittrant, D. Alquier, Effect of the excitation waveform on the average power and peak power delivered by a piezoelectric generator, Mechanical Systems and Signal Processing 133 (2019) 106278. Click here for more details.

T. Slimani Tlemcani, C. Justeau, K. Nadaud, G. Poulin-Vittrant, D. Alquier, Deposition time and annealing effects of ZnO seed layer on enhancing vertical alignment of piezoelectric ZnO nanowires, Chemosensors 7(1) (2019) 7. Click here for more details.
A. S. Dahiya, F. Morini, S. Boubenia, K. Nadaud, D. Alquier, G. Poulin-Vittrant, Organic/Inorganic hybrid stretchable piezoelectric nanogenerators for self-powered wearable electronics, Advanced Materials Technologies (2017) 1700249, 11 pp. Click here for more details.

Click here to discover our video.

Meet us at 2019 Spring Meeting of the European Materials Research Society (E-MRS)

Meet us at 2019 Spring Meeting of the European Materials Research Society (E-MRS) from May 27 to 31, 2019, in Nice, France.

Meet us at Symposium F “Materials for Energy”, with an invited presentation and a poster.

Invited presentation:

Influence of sputtering power of ZnO seed layer on the structural and morphological properties of hydrothermally grown ZnO nanowires for piezoelectric energy harvesting

Camille Justeau, Taoufik Slimani Tlemcani, Guylaine Poulin-Vittrant, Kevin Nadaud, Daniel Alquier

Using a hydrothermal synthesis method, zinc oxide (ZnO) nanowires (NWs) have been grown on ZnO/Au/Ti/Si substrates. This method shows a low temperature (70 °C) approach for growing ZnO NWs on a ZnO seed layer. ZnO films of about 50 nm thickness were deposited by radio frequency (RF) magnetron sputtering at various sputtering powers (150, 100 and 65W). The formation of ZnO seed layers and ZnO NWs was clarified using X-ray diffraction (XRD), and the surface microstructure of the prepared ZnO NWs and ZnO films was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The results show that the growth behavior of ZnO NWs is strongly impacted by the sputtering power of ZnO seed layers. The decrease of RF sputtering power leads to a diminution in the grain size of ZnO seed layers and a smaller lattice mismatch between seed layers and NWs, thus inducing a morphological improvement and a better alignment of the obtained ZnO NWs. These works aim at optimizing the integration of ZnO NWs for mechanical energy harvesting applications, and to enhance the performance of such piezoelectric devices.


Annealing and Thickness Effects of ZnO Seed Layer on Improving Alignment of ZnO NWs for Piezoelectric Nanogenerator Application

Taoufik Slimani Tlemcani, Camille Justeau, Kevin Nadaud, Guylaine Poulin-Vittrant, Daniel Alquier

Well aligned crystalline zinc oxide (ZnO) nanowires (NWs) on ZnO/Au/Ti/Si substrates were grown by the so-called “hydrothermal synthesis”. ZnO seed layers with different thicknesses ranging from 5 to 100 nm, by controlling the deposition time, were prepared by radio-frequency sputtering followed by a post-annealing treatment in air at 400°C. The effects of deposition time and annealing treatment of ZnO seed layers on the subsequent growth of ZnO NWs were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The experimental results reveal that the quality and growth behavior of ZnO NWs are strongly dependent on both the thickness and the heat treatment of the ZnO seed layers. This work is an optimization step of the facile, cost-effective and industrially scalable process flow recently developed for the fabrication of a high performance nanocomposite-based stretchable nanogenerator (SNG) on polydimethylsiloxane (PDMS) substrate. The morphological improvement of hydrothermally grown ZnO NWs may therefore lead to higher performance SNGs for the targeted application of mechanical energy harvesting in order to supply flexible and wearable electronics.

Click here for more details.

Conference “Journées Nationales sur la Récupération et le Stockage d’Energie”

We are delighted to announce the next conference « Journées Nationales sur la Récupération et le Stockage d’Energie » (JNRSE – « National Days on Energy Harvesting and Storage »), which will be held in Blois, jointly organized by GREMAN laboratory and INSA-Centre Val de Loire, May, 23rd-24th, 2019.

The aim of this conference is to bring together researchers working on energy conversion, harvesting and storage, especially at small scale, as well as the design of complete self-powered devices. Young researchers, PhD students and post-doctoral fellows, will have the opportunity to to present their works through oral presentations or posters. Moreover, invited talks from renowned French and international researchers will complete the program of the conference (all the presentations will be in English). The emergence of new collaborations, or the reinforcement of existing ones, between academia and/or industry is also one of the objectives of this conference.

The extended abstracts (maximum length 2 pages using the template available on this website) can be submitted until April 15th.

Confirmed list of invited speakers :

Armin Feldhoff, Institute of Physical Chemistry and Electrochemistry, Leibniz Universität Hannover
Jean-François Robillard, IEMN, Lille
Anne Labouret, SOLEMS S.A., Palaiseau, France
Henrik Zessin, Fraunhofer-IIS, Nurnberg, Germany
Chris Bowen, Univ. of Bath, UK
Raphaël Salot, CEA-LETI, Grenoble, France
Yang Bai, Microelectronics Research Unit, Univ. of Oulu, Finland
Mario Urso, CNR-IMM & University of Catania, Italy