| Jun 12, 2026 |
Diamond, long deemed non-piezoelectric, now shows stable voltage generation in ultrathin flexible membranes, unlocking self-powered medical sensors.
(Nanowerk News) A research team led by Professor Zhiqin Chu, Associate Professor in the Department of Electrical and Computer Engineering, and Professor Yuan Lin, Professor in the Department of Mechanical Engineering, Faculty of Engineering at the University of Hong Kong (HKU), has reported a significant piezoelectric effect in ultrathin and ultra-flexible polycrystalline diamond membranes. This pioneering discovery challenges a century-long scientific dogma that diamonds are strictly non-piezoelectric (Science Advances, “Uncovering piezoelectric effect in polycrystalline diamond membranes”).
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Since the 1900s, diamonds have been classified globally as non-piezoelectric material. Consequently, despite being a strong, hard and inert material with exceptionally high acoustic velocity, thermal conductivity, dielectric breakdown strength and ultrawide bandgap, diamond has only been used as a mechanical substrate supporting other piezoelectric material layers in microelectromechanical systems (MEMS). Indeed, the very idea of “generating electricity from diamonds” was initially deemed impractical by many.
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To overcome this limitation, the HKU research team utilised a recently developed edge-exfoliation method to fabricate an ultrathin, flexible polycrystalline diamond membrane, enabling this exceptionally hard natural material to undergo large deformations. Surprisingly, imposed bending deformation of the membrane was found to generate stable voltage signals.
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| Ultrathin polycrystalline diamond membranes respond to charged objects. (Image: Reproduced from DOI:10.1126/sciadv.aea8318, CC BY) (click on image to enlarge)
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Ensuring the utmost scientific rigour and ruling out potential environmental noise or triboelectric artefacts, the team conducted extensive mechanical cycling tests under various controlled conditions. The consistent and repeatable electrical outputs demonstrate the outstanding piezoelectric response of the diamond membrane.
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Detailed first-principle calculations revealed that this piezoelectric effect is primarily attributed to the asymmetry of grain boundaries within the diamond membrane. Specifically, charge polarisation accumulates at the grain boundaries as the imposed deformation increases, which in turn creates a potential difference between the upper and lower surfaces of the membrane.
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Given diamond’s unparalleled biocompatibility, chemical stability, and non-toxicity, this finding demonstrates the huge potential of diamond in medical and energy applications. For example, piezoelectric diamond membranes could be used in future implantable medical devices to serve as self-generating power source or deformation sensors.
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This research not only pioneers an entirely new avenue for the functionalization of diamond materials but also provides an innovative solution for the development of next-generation high-reliability micro-energy systems and self-powered sensing technologies.
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