A*STAR Develops Self-Powered Photodetector for Wireless Sensing

Placing sensors in remote areas for monitoring the environment is often inefficient when it comes to powering those devices. In most cases, those sensors run on solar or battery power like the seismometers scattered around Yellowstone Park that monitor earthquakes. Most of those sensors are buried in order to get accurate readings and need to be dug up on an annual basis to replace dead batteries.

The same can be said for light detection sensors, like those found in remote controls or other mobile devices as they require a steady power source to maintain their functions. Researchers from A*STAR have developed a new type of photodetector that overcomes those limitations of power requirements by having the device supply its own power.

Typical photodetectors are made using crystalline-based semiconductor materials, which require a buildup of energy (provided by the sensor) to operate an electrical circuit; however, that energy buildup tends to bleed over time, making them wholly inefficient. To overcome those energy losses, the researchers replace those semiconductor materials with ferroelectric compounds, which can separate electrical charges and store them separately with relatively low loss of power.

The Ferroelectric photodetectors are capable of generating larger electrical voltages than those of crystalline architecture, which allows them to power other devices connected to the sensors. The redesigned photodetector was connected to a proprietary electrical circuit that is opened and closed using a piezoelectric-cantilever switch to generate electricity, which is then stored in the photodetector as well as a capacitor. Once a sufficient charge is built up in the capacitor, the cantilever switch closes the electrical circuit and activates an RF transmitter that can then send accumulated data wirelessly to monitoring stations for processing.

While the photodetectors have a wide range of applications, the technology is still under development and probably will not be available on the commercial market anytime soon.

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