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Ultrashort-pulsed laser processing and solution based coating in roll-to-roll manufacturing of organic photovoltaics

: Hördemann, C.; Hirschfelder, K.; Schaefer, M.; Gillner, A.


Kafafi, Z.H. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Organic photovoltaics XVI : 10 - 13 August 2015, San Diego, California, United States
Bellingham, WA: SPIE, 2015 (Proceedings of SPIE 9567)
ISBN: 978-1-62841-733-3
Paper 956712
Conference "Organic Photovoltaics" <16, 2015, San Diego/Calif.>
Fraunhofer ILT ()

The breakthrough of flexible organic electronics and especially organic photovoltaics is highly dependent on cost-efficient production technologies. Roll-2-Roll processes show potential for a promising solution in terms of high throughput and low-cost production of thin film organic components. Solution based material deposition and integrated laser patterning processes offer new possibilities for versatile production lines. The use of flexible polymeric infstrates brings along challenges in laser patterning which have to be overcome. One main challenge when patterning transparent conductive layers on polymeric infstrates are material bulges at the edges of the ablated area. Bulges can lead to short circuits in the layer system leading to device failure. Therefore following layers have to have a sufficient thickness to cover and smooth the ridge. In order to minimize the bulging height, a study has been carried out on transparent conductive ITO layers on flexible PET in fstrates. Ablation results using different beam shapes, such as Gaussian beam, Top-Hat beam and Donut-shaped beam, as well as multi-pass scribing and double-pulsed ablation are compared. Furthermore, lab scale methods for cleaning the patterned layer and eliminating bulges are contrasted to the use of additional water based sacrificial layers in order to obtain an alternative procedure suitable for large scale Roll-2-Roll manufacturing. Besides progress in research, ongoing transfer of laser processes into a Roll-2-Roll demonstrator is illustrated. By using fixed optical elements in combination with a galvanometric scanner, scribing, variable patterning and edge deletion can be performed individually.