Solution-Processable Superatomic Thin-Films.

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Chemistry

Background:

• Atomically precise nanoscale clusters can form crystalline ionic solids via electrostatic interactions.
• Crystallization of these clusters into ordered structures limits their potential applications.

Purpose of the Study:

• To investigate the frustration of electrostatic interactions in nanoscale clusters using flexible side-chains.
• To develop novel amorphous superatomic materials with tunable properties for electronic and thermoelectric applications.

Main Methods:

• Synthesized large nanoscale clusters with long, flexible side-chains to frustrate electrostatic interactions.
• Solution-processed these clusters into amorphous and homogeneous thin-films.
• Characterized the electrical, thermal, and optical properties of the resulting superatomic materials.

Main Results:

• Achieved ionic superatomic materials that remain amorphous, preventing crystallization.
• Demonstrated tunable compositions with exceptionally high electrical conductivity (up to 300 S/m).
• Observed ultra-low thermal conductivity (0.05 W/m·K) and high optical transparency (up to 92%).
• Fabricated thin-film thermoelectrics with promising, unoptimized ZT values of 0.02.

Conclusions:

• Ionic superatomic materials can be processed into amorphous thin-films by controlling inter-cluster interactions.
• These amorphous materials exhibit unique properties not found in crystalline counterparts.
• Superatomic thin-films represent a promising new class of materials for electronic and thermoelectric devices.