A team of researchers at IISER-Kolkata in India has developed a technique for printing flexible electronics such as radio frequency identification devices. The technique uses laser driven micro-bubbles to write or make patterns on transparent surfaces.
Flexible electronics are based on materials called conducting polymers, plastic or resin surfaces, which need to be "doped" or laced with synthetic materials to enhance conductivity. The process of synthesis, doping, and patterning/lithography for designing circuits is mostly separate, and usually complicated and lengthly.
"Through the technique developed by us, we have basically proven feasibility and also shown that one can simultaneously achieve several things (synthesizing the polymer, doping it, and patterning it) in a single shot," Ayan Banerjee at the Department of Physical Sciences, Indian Institute of Science Education and Research, Kolkata. The researchers call their method "micro-bubble based writing" which has been developed over the last four years. "Our method basically needs a microscope, a laser, and some optical components such as mirrors, etc. - a total investment of around Rs 1.5 lakhs should be enough for a basic setup," Banerjee said.
Usuallyy, the 'printing' for printed electronics is carried out through inkjet printers or screen printers. "These are not high cost - but may suffer from precision - the typical resolution for 600 dpi (dots per inch) inkjet printing is around 40 microns. We can go much lower than that. We shine a very tightly focused laser into the sample. This tightly focused laser is essentially what is known as optical tweezers - something which can spatially confine and also controllably move microscopic objects through a fluid medium," Banerjee explained.
"In the near future, we will be attempting to make micro-capacitors having very large capacitance values (supercapacitors) and hetero-structured electronic devices out of this method. Imagine integrated circuits that are used in consumer electronics which so thoroughly dominate our daily lives being made by writing the circuits merely by pulling micro-bubbles in a liquid by a laser," he added.
The team comprises of Subhrokoli Ghosh, Santu Das, Shuvojit Paul, Preethi Thomas, Basudev Roy, Apartha Mitra, and Soumyajit Roy. The development is published in the 'Journal of Materials Chemistry C'.
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