Grain Boundary-Induced Piezoelectricity in Ultrathin Diamond Membranes

Overturning a century-old material assumption that bulk diamond is non-piezoelectric, researchers fabricated flexible micro-thin polycrystalline diamond membranes. First-principles calculations revealed that mechanical bending induces structural charge asymmetries across internal crystal grain boundaries, producing a strong and repeatable piezoelectric voltage. ## Why It Matters The integration of this discovery with the distinctive properties of ~5 mm diamond membranes is anticipated to accelerate progress in diamond-based technologies for energy harvesting, intelligent sensing, and wearable electronic devices.