Synergistic Tuning of Doping Efficiency and Charge Transport in n-Type Thermoelectric Polymers via Rational Backbone...

Area of Science:

• Materials Science
• Organic Electronics
• Thermoelectrics

Background:

• N-type organic thermoelectric polymers generally show lower performance than p-type counterparts.
• Developing efficient n-type polymers is crucial for thermoelectric generators.

Purpose of the Study:

• Investigate the role of interunit orbital interactions in governing thermoelectric performance.
• Design and synthesize novel n-type polymers based on cyanothiophene-flanked diketopyrrolopyrrole (CDPP).

Main Methods:

• Synthesized two n-type polymers: PCDPP-DPP and PCDPP-BTzOR.
• Compared their structural, electronic, and charge transport properties.
• Evaluated their thermoelectric performance after n-doping.

Main Results:

• PCDPP-DPP exhibited superior charge transport and doping response compared to PCDPP-BTzOR.
• PCDPP-DPP achieved higher electron mobility (0.191 cm² V⁻¹ s⁻¹) and electrical conductivity (25.71 S cm⁻¹).
• PCDPP-DPP attained a high power factor (23.52 μW m⁻² K⁻²) and ZT of 0.07.

Conclusions:

• Orbital interaction engineering is an effective strategy for enhancing n-type thermoelectric polymers.
• Optimized interunit orbital interactions in PCDPP-DPP promote electronic delocalization and mitigate charge trapping.
• This work paves the way for high-performance organic thermoelectric devices.