Read: A new study applies liquid metal synthesis to piezoelectric materials, which could pave the way for future wearable electronics.
As researchers look at ways to advance the future of flexible, wearable electronics and biosensors, a new technique for synthesizing specific materials could be the answer.
Materials like atomically thin tin monosulfide (SnS) have been predicted to exhibit inherent flexibility and strong piezoelectric properties, converting mechanical force or motion into electrical energy. Piezoelectric devices could sense sudden changes in acceleration and be used to trigger airbags in cars, while more sensitive devices could recognize changes in the orientation of cell phones or form the basis of sound and pressure sensors.
More sensitive piezoelectric materials can utilize small voltages generated by very small mechanical displacements, vibrations, bending, or stretching to power tiny devices such as biosensors embedded in the human body, eliminating the need for an external power source.
These impressive properties make materials such as SnS likely candidates for bendable nanogenerators that could be used in wearable electronics or internally self-powered biosensors. However, such potential applications are limited by the difficulty of synthesizing large, highly crystalline monolayers of tin sulfide due to strong coupling between the layers.
But a new collaborative study between RMIT University and the University of Sydney, New South Wales, published in Nature Communications, appears to have solved this problem by synthesizing the material using a new liquid metal technology developed at RMIT.
High durability and flexibility
This unprecedented synthesis technique involves the formation of van der Waals flakes on the surface of tin when it is melted by exposure to surrounding hydrogen sulfide gas. The gas breaks down at the interface and vulcanizes the melt surface, forming SnS.
This liquid-metal-based approach allows scientists to extract homogeneous and large-scale monolayers of SnS with minimal grain boundaries.In addition, measurements have confirmed that the material has an unusually high peak-generated voltage and loaded power, as well as high durability and flexibility.
According to this study, the findings are a step toward piezoelectricity-based, flexible, energy-harvesting wearables, as the synthesized monolayer SnS can be commercially used in nanopower generation devices or sensors that harvest mechanical movements of the human body.