Self-emitting screen coating for mobile phones

Chinese scientists are developing a transparent material that can be used to cover the surface of touch screens. This material will emit electricity every time someone touches the screen.

Touch the touchscreen to charge. Photo: TZIDO SUN

According to Live Science, scientists at Lanzhou University, China, believe that mechanical energy from operations on the touch screens of electronic devices can be converted into electricity to charge phone batteries, significantly extending the working time of handheld devices.

They developed a new material, based on a transparent silicone rubber called PDMS. Conducting wires made of lead zirconate titanate material only about 700 nanometers wide, about 140 times thinner than the width of a human hair, are embedded in the rubber.

Once the rubber solidifies, the researchers use an electric field to align the nanowires in the rubber in columns. This alignment sets the coating’s electrical and visual properties. Whenever a mechanical stress on the rubber, such as a touch on a screen, causes the wires to bend, a current is generated due to piezoelectricity. Because the nanowires are aligned, they respond to multiple touches at once, generating as much energy as possible.

Because the wires are so small, the entire coating would be nearly transparent. As such, the nanowires “could harvest energy on a display without affecting its normal operation,” says study author Yong Qin.

In addition, when the screen is covered, if viewed from an angle other than the device owner's angle (looking straight at the screen), the nanowires will diffract light and cannot be seen clearly, protecting the privacy of the device owner.

In current experiments, touching the coating generated a current of 0.8 nanoamps, about one-millionth of the current used in hearing aids. The scientists also said that further research could help generate larger currents, which could increase the efficiency of charging batteries for mobile devices. Electrical signals from the nanowires could also help develop more sensitive touchscreens, according to Qin.

According to VnExpress