Hanyang Researchers Master Organic Semiconductor Doping via Solvent Control

The challenge of balancing doping strength, stability, and control has long hindered the progress of organic semiconductors. While Lewis-paired dopants—complexes formed by Lewis acids and bases—offer exceptional strength and stability, their high reactivity previously made precise adjustment nearly impossible. Professor Jaeyoung Jang and Dr. Sang Beom Kim addressed this by using solvent polarity to regulate dopant behavior during processing.

By testing the dopant pair DDQ and BCF across six different solvents, the team discovered that solvent choice acts as a gatekeeper for reactivity. In highly polar environments, solvent molecules trap BCF, preventing the pairing process. However, in solvents with moderate polarity like ethyl acetate, this capture is temporary. As the solvent evaporates, BCF is released, allowing it to pair with DDQ at a controlled rate. This mechanism enables exact tuning of doping levels, which significantly improves the thermoelectric performance of the resulting materials. This development paves the way for more efficient wearable sensors, solar cells, and IoT devices.