Two-dimensional polyaniline crystal with metallic out-of-plane conductivity

Area of Science:

• Materials Science
• Condensed Matter Physics
• Polymer Chemistry

Background:

• Linear conducting polymers typically exhibit limited conductivity between polymer strands or layers due to poor intermolecular ordering.
• Achieving efficient charge transport in the extended dimension of conducting polymers is a significant challenge in materials science.

Purpose of the Study:

• To engineer a novel two-dimensional conducting polymer with enhanced out-of-plane electrical conductivity.
• To investigate the charge transport mechanisms and electronic properties of multilayer-stacked polyaniline crystals.

Main Methods:

• Synthesis of a multilayer-stacked two-dimensional polyaniline (2DPANI) crystal.
• Characterization using electron spin resonance spectroscopy and first-principles calculations.
• Electrical transport measurements via terahertz and infrared nanospectroscopy, conductive scanning probe microscopy, and micro-devices.

Main Results:

• The 2DPANI crystal demonstrated metallic out-of-plane charge transport with high electrical conductivity (up to ~15 S cm⁻¹).
• Significant electron delocalization and strong interlayer electronic coupling were observed, facilitated by Cl-bridged stacking.
• Transport measurements revealed comparable in-plane and out-of-plane conductivity, with conductivity increasing upon cooling.

Conclusions:

• The multilayer-stacked 2D conducting polymer design enables efficient out-of-plane charge transport, overcoming limitations of traditional polymers.
• This approach holds potential for achieving three-dimensional metallic conductivity in polymer-based materials.
• The findings open new avenues for designing advanced conductive polymers for electronic applications.