Printing electronics gets easier with IISER-Kolkata technology

Printing flexible electronics - such as radio frequency identification devices or RFID tags used to unlock hotel rooms or smart windows in planes - just got easier, thanks to Indian scientists.

Meeting the growing demand for printed, flexible electronics, a team of researchers at IISER-Kolkata has developed a technique that uses laser driven micro-bubbles to literally "write" or pattern on transparent surfaces.

Printed electronics is one of the fastest growing areas in the electronics industry primarily due to its very low cost and flexibility.

These 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 often complex and time consuming.

"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, told IANS on Wednesday.

The researchers call it "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," he said about its cost-effectivity.

Typically, 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.

The team anticipates that their method may provide a new paradigm in solution printed electronic circuits and devices in the future.

"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' in June.

--IANS

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