Mitra Dana, Mitra Kalyan Yoti, Buchecker Georg, Görk Alexander, Mousto Maxim, Franzl Thomas, Zichner Ralf
Fraunhofer Institute for Electronic Nano Systems ENAS, 09126 Chemnitz, Germany.
Hamamatsu Photonics Deutschland GmbH, 82211 Herrsching am Ammersee, Germany.
Polymers (Basel). 2024 Oct 14;16(20):2896. doi: 10.3390/polym16202896.
The implementation of the laser sintering for inkjet-printed nanoparticles and metal organic decomposition (MOD) inks on a flexible polymeric film has been analyzed in detail. A novel approach by implementing, next to a commonly 3.2 mm diameter spot laser optic, a line laser optic with a laser beam area of 2 mm × 80 mm, demonstrates the high potential of selective laser sintering to proceed towards a fast and efficient sintering methodology in printed electronics. In this work, a multiplicity of laser parameters, primary the laser speed and the laser power, have been altered systematically to identify an optimal process window for each ink and to convert the dried and non-conductive patterns into conductive and functional silver structures. For each ink, as well as for the two laser optics, a suitable laser parameter set has been found, where a conductivity without any damage to the substrate or silver layer could be achieved. In doing so, the margin of the laser speed for both optics is ranging in between 50 mm/s and 100 mm/s, which is compatible with common inkjet printing speeds and facilitates an in-line laser sintering approach. Considering the laser power, the typical parameter range for the spot laser lays in between 10 W and 50 W, whereas for the line optics the full laser power of 200 W had to be applied. One of the nanoparticle silver inks exhibits, especially for the line laser optic, a conductivity of up to 2.22 × 10 S‧m, corresponding to 36% of bulk silver within a few seconds of sintering duration. Both laser sintering approaches together present a remarkable facility to use the laser either as a digital tool for sintering of defined areas by means of a spot beam or to efficiently sinter larger areas by means of a line beam. With this, the utilization of a laser sintering methodology was successfully validated as a promising approach for converting a variety of inkjet-printed silver patterns on a flexible polymeric substrate into functionalized conductive silver layers for applications in the field of printed electronics.
已详细分析了在柔性聚合物薄膜上对喷墨打印纳米颗粒和金属有机分解（MOD）油墨进行激光烧结的实现情况。一种新颖的方法是，除了常用的直径3.2毫米的点激光光学器件外，还采用激光束面积为2毫米×80毫米的线激光光学器件，这表明选择性激光烧结在朝着印刷电子学中快速高效的烧结方法发展方面具有很高的潜力。在这项工作中，系统地改变了多种激光参数，主要是激光速度和激光功率，以确定每种油墨的最佳工艺窗口，并将干燥的非导电图案转化为导电且功能化的银结构。对于每种油墨以及两种激光光学器件，都找到了合适的激光参数集，在此参数集下可以实现导电性，同时不会对基板或银层造成任何损坏。这样做时，两种光学器件的激光速度范围在50毫米/秒至100毫米/秒之间，这与普通喷墨打印速度兼容，并便于采用在线激光烧结方法。考虑到激光功率，点激光的典型参数范围在10瓦至50瓦之间，而对于线光学器件，则必须施加200瓦的全部激光功率。其中一种纳米颗粒银油墨，特别是对于线激光光学器件，在烧结持续时间的几秒钟内，电导率高达2.22×10 S‧m，相当于块状银的36%。两种激光烧结方法共同展示了一种卓越的能力，即可以将激光用作通过点光束烧结特定区域的数字工具，或者通过线光束高效烧结更大区域。由此，激光烧结方法作为一种有前途的方法成功得到验证，可将柔性聚合物基板上的各种喷墨打印银图案转化为用于印刷电子学领域的功能化导电银层。
