Accelerometer is something you most likely use every day but don’t know about. Every time you turn your phone and the video goes full screen, the accelerometer is doing its job. It is a device used to detect motion in electronics such as mobile phones. Now Australian scientists from UNSW and RMIT found a way to make production of accelerometers much cheaper and more energy-efficient.
Production costs and energy efficiency always go hand in hand, because energy is expensive. And accelerometer production requires quite a lot of it, which is why the price of these devices has been reducing slowly, despite them being present in many smart devices. Now scientists found a way to virtually print large-scale sheets of two-dimensional piezoelectric material, which can then be placed on silicon chips to make accelerometers. Piezoelectric materials are not new in electronics. They are typically found in sound and pressure sensors as well as embedded devices that are powered by vibration or bending.
Piezoelectric materials generate small voltages generated by tiny mechanical displacement, vibration, bending or stretching. You’ve probably already seen it – small piezoelectric elements are used in lighters and stoves. Typically piezoelectric materials are manufactured in large chucks of crystals. They can be broken down, but it was never possible to integrate them with silicone chips or use in large-scale surface manufacturing. That essentially meant that piezoelectric accelerometers are not possible, even though potential for air bag triggers or the devices that recognise orientation changes in mobile phones was recognized. Manufacturing smaller chunks of piezoelectric materials was extremely energy consuming, not environmentally-friendly and quite costly.
But not anymore, because scientists came up with a way how to print gallium phosphate (GaPO4), an important piezoelectric material, in a 2D format and then place it on silicon substrates or any other surface. That opens the door for a large-scale manufacture, using low-cost, low-temperature techniques. Professor Kourosh Kalantar-zadeh, author of this study, said: “As so often in science, this work builds on past successes. We adopted the liquid-metal material deposition technique we developed recently to create 2D films of GaPO4 through an easy, two-step process”.
Accelerometers are everywhere, but don’t expect this invention to lower the price of your smartphones. The truth is that accelerometers are quite a small part of the cost and the price is dictated by the market. However, it is a nice advancement, showing how big improvements can be made on smallest devices.