Piezoelectricity Discovered in Polycrystalline Membranes

Tech News Brief | Materials & Electronics

Diamond Breakthrough: Piezoelectricity Discovered in Polycrystalline Membranes

A new study published in Science Advances reports a major shift in how diamond is understood as an engineering material. Researchers led by Jixiang Jing have demonstrated that polycrystalline diamond membranes can exhibit piezoelectric behavior—a property long believed impossible for diamond.

For over a century, diamond has been classified as non-piezoelectric due to its highly symmetric crystal structure. However, the team found that grain boundaries in polycrystalline diamond break local symmetry, enabling charge polarization when the material is mechanically deformed.

Key Findings

• Strong voltage response:
  The membranes achieved a piezoelectric voltage coefficient of ~82 mV·m/N, exceeding many conventional materials such as Lead Zirconate Titanate and Barium Titanate.

• Optimal thickness effect:
  Peak performance occurs at ~5 µm thickness, where grain boundary effects are maximized.

• High durability and stability:
  Devices remained stable over 7000+ bending cycles and functioned at temperatures up to 600 K.

• Not observed in single-crystal diamond:
  The effect is unique to polycrystalline structures, confirming the role of internal interfaces.

Why It Matters

This discovery repositions diamond from a passive material—used mainly for thermal management, optics, and mechanical support—into an active functional material capable of electromechanical energy conversion.

Potential applications include:

• Energy harvesting systems

• Self-powered sensors

• MEMS and RF devices

• Wearable and flexible electronics

Industry Impact

The findings could open new pathways for CVD diamond manufacturers, enabling engineered grain structures to tailor electrical functionality alongside diamond’s well-known thermal and mechanical advantages.

As demand grows for high-performance materials in extreme environments, piezoelectric diamond may offer a unique combination of durability, thermal conductivity, and electrical responsiveness not achievable with existing piezoelectric materials.

DIASEMI Diamond membrane films available from diameter 1-300mm with thickness from 0.05mm to 1mm