A fingernail-sized piece of ceramic is squeezed in a vise, and its internal structure rearranges like clay under your fingers. Inside, orderly rows of tiny domains line up where they were once randomly oriented. After this 'massage,' the crystal lets light through almost like glass and, at the same time, generates a strong electric charge when bent or pressed.
The researchers applied this trick to a known material based on lead, magnesium, niobium, and titanium. After treatment, it produced several times more electricity per unit of force than standard counterparts. At room temperature, the coefficient was about 5000 picocoulombs per newton, and at 58 degrees Celsius, it reached nearly 11700. It's as if an ordinary spring suddenly started generating current every time it was compressed, while remaining transparent.
They immediately tested the practical use: they made a flexible patch sensor. It simultaneously measures the pulse wave (from pressure changes on the skin) and blood oxygen levels (by shining light through the skin). Such a sensor can be worn on the wrist or chest, continuously transmitting data about the body's condition.
So, squeezing in the right direction turns cloudy ceramic into a transparent smart material. Instead of complex electronics, simple mechanics paves the way for cheap, comfortable wearable health devices.
A coefficient of 11700 pC/N means: if you hang a 1-kilogram weight on the crystal, it will produce enough charge to briefly light up a tiny LED.
This material resembles the 'smart skin' from science fiction that senses touch while staying transparent, like in the movie 'Ghost in the Shell'.