Structure and Doping Optimization of IDT-Based Copolymers for Thermoelectrics

Area of Science:

• Organic electronics
• Materials science
• Thermoelectric materials

Background:

• π-conjugated backbones are crucial for organic semiconductor thermoelectric properties.
• Structure-property-function relationships guide material screening.
• Indacenodithiophene (IDT) is a key building block for conjugated polymers.

Purpose of the Study:

• To design and synthesize novel conjugated copolymers based on an IDT building block.
• To investigate the impact of polymer backbone structure on thermoelectric properties.
• To optimize materials for enhanced thermoelectric performance.

Main Methods:

• Synthesis of conjugated copolymers (P1, P2, P3) utilizing an IDT core.
• Characterization of copolymer structures and electronic properties.
• Evaluation of thermoelectric performance, including power factor, after doping.

Main Results:

• A copolymer (P3) with an alternating donor-acceptor (D-A) structure was synthesized.
• P3 exhibited a narrower band gap and higher carrier mobility compared to non-D-A analogs (P1, P2).
• The D-A copolymer (P3) achieved a power factor of 4.91 μW m⁻¹ K⁻² at room temperature after doping.

Conclusions:

• Alternating donor-acceptor structures effectively reduce charge carrier transport obstacles.
• Moderate adjustment of the polymer backbone is a viable strategy to enhance thermoelectric properties.
• The synthesized IDT-based D-A copolymer shows promising potential for thermoelectric applications.