Pushing Print on Large-Scale Piezoelectric Materials

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2D surface deposition of piezoelectric material allows the integration of piezoelectric components directly onto silicon chips

Researchers have developed a method to print large-scale sheets of two-dimensional piezoelectric material, opening new opportunities for piezo-sensors and energy harvesting. Until now, no 2D piezoelectric material has been manufactured in large sheets, making it impossible to integrate into silicon chips or use in large-scale surface manufacturing.

Gallium phosphate (GaPO4) is a piezoelectric material used in pressure sensors and microgram-scale mass measurement, particularly in high temperatures or other harsh environments. Therefore, researchers adopted the liquid-metal material deposition technique to create 2D films of GaPO4 through a two-step process.

The Two-step process

The Two-step process allows growth of large-area (several centimetres), wide-bandgap, 2D GaPO4 nanosheets of unit cell thickness. The first step is to exfoliate self-limiting gallium oxide from the surface of liquid gallium made possible by the lack of affinity between the oxide and the bulk of the liquid metal. The second step is to print that film onto a substrate and transform it into 2D GaPO4 via exposure to phosphate vapour.

Applications of the process

The new process is simple and expands the range of materials available to the industry at such scales and quality. The process is suitable for the synthesis of freestanding GaPO4 nanosheets. This synthesis method is compatible with a variety of electronic device fabrication procedures, providing a route for the development of future 2D piezoelectric materials.

This simple, industry-compatible procedure to print large surface area 2D piezoelectric films onto any substrate offers opportunities for the development of piezo-sensors and energy harvesters. Well, these materials can convert applied mechanical force or strain into electrical energy. Such materials form the basis of sound and pressure sensors, embedded devices that are powered by vibration or bending, and even the simple ‘piezo’ lighter used for gas BBQs and stovetops.