Rectification ratio and direction controlled by temperature in copper phthalocyanine ensemble molecular diodes

Area of Science:

• Organic electronics
• Molecular electronics
• Nanotechnology

Background:

• Organic diodes and molecular rectifiers are key electronic devices with current rectification abilities.
• Organic diode rectification is typically achieved via interface engineering, while molecular rectifiers rely on molecular structure modifications.

Purpose of the Study:

• To report the first observation of temperature-driven inversion of rectification direction (IRD) in ensemble molecular diodes (EMDs).
• To investigate the role of material interfaces and charge transport mechanisms in controlling rectification direction.

Main Methods:

• Fabrication of EMDs using copper phthalocyanine and its fluorinated derivatives in a vertical stack.
• Electrical measurements and band diagram analysis to study charge transport mechanisms.
• Investigation of temperature-dependent electrical characteristics.

Main Results:

• Observed temperature-driven inversion of rectification direction (IRD) in EMDs for the first time.
• Identified material interface modifying conduction mechanisms (activationless transport, Poole-Frenkel emission, phonon-assisted tunneling).
• Demonstrated current rectification dependence on the interplay of these charge transport mechanisms.

Conclusions:

• Temperature plays a crucial role in charge transport transitions, enabling IRD in EMDs.
• Findings provide fundamental understanding for controlling rectification in carbon-based electronic nanodevices.
• Represents a significant step towards rational control of rectification in organic electronics.