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Laser Digital Micro-Nano fabrication for Organic Electronics and Sensor applications

Final Report Summary - LASERMICROFAB (Laser Digital Micro-Nano fabrication for Organic Electronics and Sensor applications)

This is a summary of the project's objectives, the main technical results achieved, an overview of the dissemination and outreach activities and their impact, as well as the management actions taken so far as to ensure the achievement of all the expected results by the end of the project.
The key-objectives of the project were the development of selective micro and nano-patterning, micro-curing and micro-printing processes for specific applications such as organic electronics and sensors and subsequently the integration of the innovative aspects of Laser digital microfabrication processes in one Laser Platform.
The main research achievements of the LaserMicroFab project are summarized as follows:
-WP1: Laser thin film patterning for large area organic electronics fabrication
At the beginning of the project, WP1 activities were focused on the selection of the best candidate printable materials and substrates for the achievement of the goals of the project. Through a detailed screening process, CNRS and NTUA have concluded that low viscosity silver and copper inks, with 20-40% metal content will be utilized in this project for the fabrication of conductive patterns on PET and PEN flexible substrates. In the frame of WP1, the selective laser ablation of Al was also investigated at CNRS/LP3 and Oxford Lasers facilities. The ablation of Al thin film (thickness on the order 100 nm) was achieved with good quality for an overlap between 60% and 85% and laser energy up to 10 times the single shot ablation threshold. Selective ablation experiments were also carried out at CNRS/LP3 for structuring silver interdigitated electrodes in a flexible substrate. The resulting structures were arrays of electrodes 100 um wide with 60 um inter-electrode distance. The resistivity of the ablated electrodes is of the order of 40 ohm·cm. Characterization of the printed and patterned films has been carried out efficiently with structural characterization systems (field emission SEM, XRD, AFM, DC and RF electrical measurements, optical microscope with camera and profilometer) existing at the NTUA and CNRS/LP3 facilities. By these means, the accomplishment of the first milestone of the project “M.1. Laser patterning of nanostructured films with the following specifications: 50 nm thickness, sharp edges” has been verified. Part of the workplan for WP1 was dedicated to advanced beam delivery, and OL was in charge of transferring valuable know-how to the academic partners of this project in this field. In this respect, several pathways have been successfully tested at OL facilities, CNRS/LP3 and NTUA laboratories, employing various beam shaping configurations namely, pi-shaper, refractive beam homogenizer and TOPAG beam shaper.
-WP2: Laser digital micro-fabrication processes for sensing applications
In the frame of WP2, the Laser Induced Forward Transfer (LIFT) and laser sintering technologies were introduced to OL through the process of secondments and transfer of knowledge activities. These technologies were adopted and further developed by OL, deriving significant scientific results which were published in papers co-authored by scientists from NTUA and CNRS/LP3.The LIFT and laser sintering technologies were applied successfully for the fabrication of high resolution (down to 10 um for printing, 1 um for laser sintering) 2D highly conductive interconnects (5x bulk resistivity). The combination of LIFT of metal nano-inks and laser sintering of the resulting printed patterns lead to the accomplishment of milestone two: “M.2. Digital laser micro-fabrication of 2D metallic interconnects with the following specifications: (resolution : 10 microns for laser printing and sub-micron for selective laser curing)”. The laser printing and sintering process developed in the frame of WP2 was finally employed for the preparation of polymer/CNTs composite solutions and testing for realization of humidity sensors. The realized sensors exhibited consistent change in resistance (5-80%), and quick response time (msec). Therefore, milestone 2.2 was accomplished: “M2.2 Laser printing of sensors with the following specifications: sensitivity to pollutants under test : 10^-10M”.
-WP3: Integration of laser micro-fabrication processes and design of a laser platform
Both Laser Induced Forward Transfer and Laser sintering of thin metallic lines on flexible substrates were introduced to OL by the Academic Partners NTUA and CNRS during the secondment phase of the researchers. Initially, an evaluation of laser sources in order to find the optimal laser source specifications for the laser platform was conducted at OL facilities. The system feature evaluation process evaluated the performance of several laser sources in terms of: laser beam active stabilization/alignment fast beam scanning/positioning accuracy, LIFT module (preliminary lab-scale model), Shack-Hartmann wavefront sensing beam characterization, refractive and diffractive Beam shaping calculations (pishaper, TOPAG, Holo-or, EKSMA), lens array beam homogenisation mechanical integration (Suss microoptics), probe beam deflection prototype unit for real-time detection of laser intensity sintering thresholds (lower end below which no sintering achieved, upper end above which ablation instead of sintering occurs).
Sintering experiments with top hat and Gaussian beam profiles have been carried out in order to investigate the effect of beam profile on the sintering result. Efficient sintering has been accomplished with both profiles. At the end of the project, the Flexelase laser system, a laser platform incorporating LaserMicroFab’s technology for laser printing, sintering and patterning, was built up by OL and is currently offered for R&D purposes only. In this respect, milestone 3 has been accomplished: “M3.1 Integration of the laser digital micro-fabrication concepts in one laboratory prototype”
The dissemination of experimental results derived from research activities has been very successful, with 10 publications in peer-reviewed scientific journals, 2 scientific book chapters and a large number of participations in conferences (50) throughout the project. Moreover, five workshops have been organized in total, with the participation of researchers involved in this project and the attendance of a large number of external researchers. Emphasis has been given to outreach activities (17 in total), including presentations and seminars to the general public, participation in "science for all" events and social media promotion of the LaserMicroFab project. In addition, the project's website ( has been launched at the beginning of the project (March 2013) and its content has been continuously updated by the NTUA team ever since. A large number of visits has been recorded since its release.
As regards the exploitation of results, OL achieved to exploit the project’s outcomes by releasing a new product, the FlexeLase OL laser system described above at InnoLAE 2016. Moreover, commercial interest was expressed to OL from four UK end users for LIFT printing in organic electronics including local manufacturers of RFID antennas, organic transistors for logic operations, hybrid integration on silicon and glass manufacturers. Such tangible progress of the industrial partner in LaserMicroFab indicates the great potential for success of the project in terms of near-term commercial exploitation.
The management activities of the project were implemented to ensure the successful completion of all scientific and training objectives within LaserMicroFab. During the course of the 48 months project, a wide variety of management tasks were organised and delivered according to the timeline of the Annex I. The management work was carried out by NTUA and was also focused on preparation and monitoring of the recruitment and secondment of the Researchers, the training events, the dissemination tasks and the outreach activities. More specifically, the secondments and the recruitments plan and procedure was rescheduled at the midterm of the project and a new partners was introduced (AMU) to ensure the smooth implementation of the work schedule.
In this context, the Transfer of Knowledge (TOK) actions have been carried out according to Annex
I. Secondments have taken place between the industrial and the academic partners, ensuring the transfer of knowledge from the home to the host organization and vice-versa. Three Experienced Researchers have been recruited; one to each partner. All involved fellows have been trained in their home or host institutions, have attended soft skill courses and participated in workshops organized by the consortium. Moreover, emphasis has been given to the self-evaluation actions and in this context, all fellows have filled in questionnaires about their overall experience of the project and have drafted personal career development plans. The current level of achievement of the project's objectives guarantees a significant impact on the market potential of Oxford Lasers (SME partner) and the research excellence of the NTUA and the CNRS/LP3 (academic partners) at the fields of laser materials engineering and organic electronics.
LaserMicroFab has achieved to exploit the unique strengths of the EU scientific community by providing excellent collaboration between top scientists, professionals and experts in academia, industry and SMEs and translating their scientific expertise into a novel platform within a competitive timeframe. During the four years of the project, the Consortium as a whole has managed to generate significant research results which promote the European research excellence to a great extent. Moreover, the research network that has been established for the purposes of the project between the three beneficiaries has strongly enhanced the role of Europe as a key player in applied research and advanced technology applications in the fields of advanced materials, photonics and organic and large area electronics. The project has achieved to stimulate and attract many young scientists and provide them top level targeted training and unique networking and career development opportunities. In addition, LaserMicroFab has recruited its researchers on equal opportunity basis and one third of the researchers involved in the project were female scientists.