Imec will actively participate
in a new European project called IMPROV (‘Innovative mid-infrared high-power
source for resonant ablation of organic based photovoltaic devices’) that
aims at the investigation, development and realization of a fibre integrated
short-pulse mid-infrared laser source. The industrial application driver is
the development of a laser source for the fabrication of organic solar cells.
The new source will offer advantages over existing systems in terms of parameter
specifications, flexibility, reliability and usability.
The new fibre laser source will bring a solution for the fabrication of organic
flexible devices, in particular for the patterning of organic solar cells. Conventional
processing techniques can either not cope with selectivity issues or are too
complex and costly to be compatible with an industrial environment. The proposed
solution will provide a reliable, compact and maintenance free pulsed mid-IR
source that allows resonant infrared laser ablation (RIA) of the polymer, a
technique that is selective in respect of processing a diversity of polymers.
The laser system can therefore be more largely applied to other polymer and
organic materials processing needs as well as in other ICT or medicine applications.
The laser will combine a short pulse thulium all-fibre laser operating around
2µm with a subsequent wavelength conversion stage. It will operate in
the wavelength region from 2.5µm to 11µm with a pulse energy of
up to 30µJ, a pulse duration between tens to hundreds of picoseconds and
a repetition rate between 0.1 to 1MHz.
For a compact and integrated solution, the best configuration is combining
a master oscillator power amplifier (MOPA) all-fibre laser with a quasi-phase
matched GaAs crystal for wavelength conversion. For the MOPA pump source different
integration aspects will be addressed in order to fully benefit of a waveguide
device. These include the development of fibre-coupled saturable absorbers,
large mode area (LMA) photonic crystal fibres (PCF) with functionalities regarding
wavelength tuning capability, mode-filtering and high power operation, pump/signal
combiners based on LMA-PCFs and novel concepts for fibre amplifiers with integrated
core-pumping schemes. The wavelength conversion unit will be realized with integrated
wavelength tunability and structural design.
Within the project, imec will lead the work package on ‘resonant infrared
ablation for structuring organic PV’ and will be responsible for the preparation
of the process evaluation set-up and for ablation tests using the developed
laser source. Imec is well equipped for this task as it has strong experiences
in developing solar cells and plastic electronics, assembly of various substrates,
e.g. thin film technology on flexible and stretchable substrates bringing together
expertise from electronics, mechanics, physics and chemistry. Therefore, imec
is in the position of analyzing the ablation results with respect to the laser
parameters. These important results will be applied as feedback for adjusting
the final laser parameters. Imec’s work in IMPROV will be performed at
imec’s Centre for Microsystems Technology (CMST) at Ghent University.
The consortium, coordinated by Dr. Dieter Wandt, Laser Zentrum Hannover, represents
the whole value chain including exploitation and this will significantly improve
the competitiveness of related European industry and strengthen Europe’s
scientific and technology base.