Plate Nº 61 · recorded October 10, 2026
PhysicsReported finding
Diamonds Can Generate Electricity, Hong Kong Scientists Discover
HKU researchers have overturned a century-old assumption: ultrathin, flexible diamond membranes produce a repeatable piezoelectric voltage when bent, opening paths to self-powered implants.
By Marcus Bennett5 min read918 words
In brief
- The study was published in Science Advances on August 31, 2026 (vol. 12, issue 12; DOI: 10.1126/sciadv.aea8318).
- Diamond had been classified as non-piezoelectric since the early 1900s — an assumption the HKU result overturns.
- Ultrathin polycrystalline diamond membranes produced stable, repeatable voltage signals when flexed.
- First-principles calculations trace the effect to asymmetric charge polarization at grain boundaries.
- Potential applications include self-powered medical implants and self-powered sensing technologies.
Researchers at the University of Hong Kong (HKU) have shown that diamond can generate electricity when bent, overturning a scientific assumption that has stood since the early 1900s. The finding, published in Science Advances on August 31, 2026, demonstrates a strong, repeatable piezoelectric effect in ultrathin, flexible diamond membranes.
Piezoelectricity is the ability of certain materials to produce an electrical voltage when they are mechanically deformed — squeezed, stretched, or bent. Quartz crystals in watches and lighters exploit this property. Diamond, however, has been classified as non-piezoelectric for more than a century, meaning engineers never expected it to generate voltage under mechanical stress.
Professor Zhiqin Chu, Associate Professor in HKU's Department of Electrical and Computer Engineering, and Professor Yuan Lin, Professor in the Department of Mechanical Engineering, led the research.
Why did everyone think diamond couldn't do this?
Diamond is famous for its extreme properties. It combines exceptional hardness, strength, chemical stability, high acoustic velocity, outstanding thermal conductivity, high dielectric breakdown strength, and an ultrawide bandgap — a measure of the energy needed to make the material conduct electricity.
Yet in microelectromechanical systems (MEMS) — tiny machines built at the microscale that combine mechanical and electrical components — diamond has played only a supporting role. Engineers used it as a structural scaffold for other piezoelectric materials, never as the electricity-generating element itself.
The reason dates back to classical crystal physics. Diamond's symmetric atomic structure was thought to rule out the charge separation needed for piezoelectricity. As a result, the idea of generating electricity from diamond was long considered impractical.
How did the team make diamond bend?
Bulk diamond is rigid. It does not flex appreciably, so any piezoelectric response would be vanishingly small and impossible to measure. The HKU team solved this by making the material far thinner.
They used a recently developed technique called edge exfoliation to peel off an ultrathin, flexible polycrystalline diamond membrane. Polycrystalline means the material consists of many tiny diamond crystals fused together, rather than one single continuous crystal. Thinning diamond to this extreme degree let it bend far more than bulk diamond ever could.
When the researchers deliberately flexed the membrane, they detected stable voltage signals.
Skeptics might reasonably ask whether the signal came from somewhere else. So the team ran extensive mechanical cycling experiments under carefully controlled conditions. These tests were designed to rule out environmental interference and triboelectric effects — spurious electrical signals that arise when two surfaces contact or rub against each other, such as a balloon rubbing on hair.
The voltage appeared consistently and repeatedly. That repeatability provided strong evidence that the diamond membrane itself was producing a genuine piezoelectric response.
What causes the effect?
To explain their measurements, the researchers performed detailed first-principles calculations — simulations rooted in the fundamental physics of the material's atoms and electrons, rather than fitted approximations.
Their analysis points to the grain boundaries inside the polycrystalline membrane. These boundaries are the interfaces separating the many tiny diamond crystals that make up the material.
The simulations revealed an asymmetry at those boundaries. When the membrane bends more strongly, electrical charge polarization builds up around them. This creates a difference in electrical potential between the upper and lower surfaces of the membrane — and that difference is the voltage the researchers measured.
In other words, the effect depends on the material being polycrystalline and thin. A perfect single crystal of diamond, thick and rigid, would not show it.
What could this be used for?
The discovery is preliminary, and the researchers themselves frame the applications as possibilities rather than products. Still, the direction is promising because diamond brings rare advantages: it is highly biocompatible, chemically stable, and non-toxic.
Potential future uses include:
- Self-powered medical implants. Piezoelectric diamond membranes could serve as self-generating power sources inside implantable devices, harvesting energy from the body's own motion.
- Deformation sensors. Because the voltage scales with bending, the membranes could detect mechanical deformation in medical and industrial settings.
- High-reliability micro energy systems. The work could support next-generation energy technologies where durability matters.
- Self-powered sensing technologies. Sensors that generate their own electricity would not need batteries or external wiring.
More broadly, the findings give diamond an active electrical function for the first time, rather than limiting it to a passive structural role.
How solid is the evidence?
The study has clear strengths. The voltage signals were stable and repeatable across extensive mechanical cycling, and the team took care to exclude confounding effects such as triboelectricity. The first-principles calculations offer a physical mechanism that matches the observations.
Limitations remain. The research demonstrates the effect in laboratory membranes under controlled conditions; it does not yet show working devices, long-term durability in real environments, or power output at practical levels. Whether piezoelectric diamond can move from the lab bench into implants and micro energy systems will require substantial further engineering.
Even so, the result redraws a boundary that has defined diamond physics for over a hundred years. A material long treated as electrically inert, useful only for its hardness, has now shown it can generate its own voltage — provided you make it thin enough to bend.
The paper, "Uncovering piezoelectric effect in polycrystalline diamond membranes," appears in Science Advances, volume 12, issue 12 (DOI: 10.1126/sciadv.aea8318). First author Jixiang Jing led a twelve-person team including researchers Bicong Wang, Yumeng Luo, Yicheng Wang, Zhongqiang Wang, Yiyao Liu, Dong-Keun Ki, Xinghua Shi, Qi Wang, Kwai Hei Li, Yuan Lin, and Zhiqin Chu.
via hku.hk (Original)