Enhanced Output Performance of All-Solution-Processed Organic Thermoelectrics: Spray Printing and Interface...

Area of Science:

• Materials Science
• Energy Harvesting
• Organic Electronics

Background:

• Organic thermoelectric generators (TEGs) offer flexible and low-cost energy harvesting potential.
• Performance limitations of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) TEGs are often linked to high module resistance.
• Interface engineering is crucial for optimizing charge transport in organic electronic devices.

Purpose of the Study:

• To develop organocompatible strategies for enhancing the output performance of all-solution-processed PEDOT:PSS TEGs.
• To investigate the impact of additive spray printing and functionalized polymer interlayers on module resistance and thermoelectric output.
• To demonstrate scalable fabrication of high-performance flexible PEDOT:PSS TEGs.

Main Methods:

• Additive spray printing of PEDOT:PSS layers to achieve controlled thickness and reduced sheet resistance.
• Insertion of ultrathin silane-terminated polystyrene (PS) interlayers to improve contact resistivity between PEDOT:PSS and Ag interconnects.
• Characterization of electrical properties using the transmission line method and analysis of carrier injection mechanisms via the Richardson equation.

Main Results:

• Spray printing enabled deposition of 1-μm-thick PEDOT:PSS films with a sheet resistance of 16 Ω sq^-1.
• PS interlayers reduced contact resistivity from 6.02 × 10^-2 to 2.77 × 10^-2 Ω cm² by facilitating carrier injection.
• A 74-leg flexible PEDOT:PSS TEG demonstrated an open-circuit voltage of 9.21 mV and output power of 2.23 nW at ΔT = 10 K.

Conclusions:

• Spray printing and PS interlayers are effective organocompatible strategies to enhance PEDOT:PSS TEG performance.
• Interface engineering significantly lowers module resistance and improves charge carrier injection efficiency.
• The developed methods offer scalable, plastic-compatible processing for flexible thermoelectric energy harvesting applications.