Researchers fabricate pressure sensors that use paper as medium

Bengaluru: Researchers at the Indian Institute of Science (IISc) have fabricated pressure sensors that use paper as the medium.

Several industrial, automotive and healthcare applications rely on accurate and precise measurement of pressure.

Flexible and wearable pressure sensors are typically fabricated using petroleum-based polymers. The solid waste generated from using such non-biodegradable plastics is harmful for the environment.

To avoid this issue, researchers at the IISc have now fabricated pressure sensors that use paper as the medium.

A pressure sensor detects physical pressure and converts it into an electrical signal that is displayed in the form of a number indicative of its magnitude.

Nowadays, paper-based electronic devices are gaining greater attention owing to their natural biodegradability, excellent flexibility, porous fibrous structure, light weight, and low cost.

However, paper-based sensors developed so far have certain disadvantages, according to Bengaluru-headquartered IISc.

"In any sensor, there is always a trade-off between sensitivity and dynamic range. We want to have high sensitivity. Sensitivity is essentially a measure of the smallest entity (amount of pressure) that we can detect. And we want to sense that quantity over an extensive range," said Navakanta Bhat, Professor at the Centre for Nano Science and Engineering (CeNSE) and corresponding author of the paper published in the 'ACS Sustainable Chemistry & Engineering'.

His team has proposed a design for the paper sensor that, by virtue of its structure and multilayering, achieves high sensitivity and can detect a broad range of pressures (0-120 kPa) with a response time of one millisecond, IISc said in a statement on Tuesday. The sensor is made of plain and corrugated cellulose papers coated with tin-monosulfide (SnS) stacked alternatively to form a multi-layered architecture. SnS is a semiconductor that conducts electricity under specific conditions.

"Paper in itself is an insulator. The major challenge was choosing an appropriate 3D device structure and material to give conductive properties to paper," said Neha Sakhuja, a former PhD student at CeNSE and the first author of the paper.