Improving electron injection of organic light-emitting transistors via interface layer design.

Area of Science:

• Organic electronics
• Semiconductor device physics

Background:

• Ambipolar transport is essential for high-performance organic light-emitting transistors (OLETs).
• Ineffective electron injection, especially in symmetric device geometries, often hinders achieving ambipolar characteristics.

Purpose of the Study:

• To enhance electron injection and achieve ambipolar transport in OLETs.
• To explore the use of a specifically designed organic interface layer for improved device performance.

Main Methods:

• Incorporation of a 3,7-di(2-naphthyl)dibenzothiophene S,S-dioxide (DNaDBSO) organic interface layer beneath gold electrodes.
• Fabrication and characterization of 2,6-diphenylanthracene-based OLETs with the DNaDBSO layer.
• Analysis of electron injection, mobility, and electroluminescent properties under varying gate voltages.

Main Results:

• The DNaDBSO interface layer significantly enhanced electron injection and mobility.
• Effortless achievement of ambipolar transport with hole mobility (μmaxh) of 2.17 cm² V⁻¹ s⁻¹ and electron mobility (μmaxe) of 0.053 cm² V⁻¹ s⁻¹.
• Demonstration of efficient electron injection and intrinsic ambipolar transport through observed shifts in the electroluminescent region with gate voltage modulation.

Conclusions:

• The DNaDBSO interface layer, leveraging an interfacial dipole effect, effectively overcomes electron injection limitations in OLETs.
• This strategy provides a new pathway for interface engineering in electroluminescent devices.
• Enables high-performance, simple-structured OLETs for various applications.