Large Piezoelectricity in a Dynamic Metal-Organic Framework With Negative Linear Compressibility

Area of Science:

• Materials Science
• Solid-State Physics
• Nanotechnology

Background:

• Piezoelectric metal-organic frameworks (MOFs) show promise for energy harvesting and sensing.
• Current MOF piezoelectric performance is limited by design and screening challenges.
• Conventional piezoelectric ceramics and polymers face limitations in specific applications.

Purpose of the Study:

• To investigate the enhancement of piezoelectricity in MOFs through negative linear compressibility (NLC).
• To demonstrate a new design strategy for high-performance piezoelectric materials.
• To explore the potential of NLC in MOFs for energy harvesting and sensing applications.

Main Methods:

• Utilized a dynamic MOF, Ni(PyC)2·DMF (IISERP-MOF2), exhibiting NLC along its crystallographic b-axis.
• Characterized the piezoelectric properties, focusing on the piezoelectric voltage coefficient (g33).
• Fabricated MOF/polymer composite devices for performance evaluation in energy harvesting and ultrasonic sensing.

Main Results:

• IISERP-MOF2 demonstrated a high piezoelectric voltage coefficient (g33) of 859.4 × 10^-3 Vm/N, significantly exceeding BaTiO3 and PVDF.
• The NLC principle was validated in two additional MOFs and a molecular framework.
• MOF/polymer composites achieved superior energy harvesting (1.4x) and underwater ultrasonic sensing (2.4x) compared to PZT and PVDF devices.

Conclusions:

• Negative linear compressibility is a key factor for enhancing piezoelectricity in noncentrosymmetric crystals.
• This principle offers a viable pathway for designing advanced piezoelectric MOFs.
• NLC-based MOFs present a new generation of materials for efficient energy harvesting and sensitive detection systems.