Polymer-like alloy for flexible electronic devices
doi:10.1038/nindia.2019.77 Published online 16 June 2019
Researchers have synthesised a semi-crystalline and lightweight polymer-like dielectric alloy by heating and melting a mixture of sulphur and selenium, two brittle elements1. This alloy shows promising mechanical and insulating properties that could potentially be exploited in fabricating flexible electronic devices.
Conventional dielectrics, which are a type of electrical insulator, are either ceramics or polymers. However, these materials cause large energy losses and are unstable at low voltages.
In search of a stable and flexible material, an international research team including a scientist from the Indian Institute of Technology in Kharagpur produced the alloy by melting sulphur and selenium simultaneously in an atmosphere filled with an inert gas.
The researchers, led by Pulickel M Ajayan, then explored the alloy’s mechanical and insulating properties. When a specific load was applied separately on pure sulphur or selenium, both displayed their brittleness. The same load, when applied on the alloy, deformed it into a thin sheet. On removing the load, the alloy regained its original shape.
The alloy also exhibited visco-elastic behaviour and mechanical flexibility in the same way soft polymers do. Its dielectric constant was comparable to some of the conventional metal oxides and was 10 times higher than polymers.
Besides showing elasticity at room temperature, the alloy also showed insignificant dielectric loss, loss of energy that goes into heating a dielectric material in a varying electric field, at higher frequencies. Such a property suggests that it could be used as an absorber in dampening unwanted resonances in electronic devices.
1. Susarla, S. et al. High-K dielectric sulfur-selenium alloys. Sci. Adv. 5, eaau978510 (2019)