Conductivity Boost by the Loading-Soaking Doping (LSD) Procedure: A Crystalline Structure-Preserving Strategy

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Molecular doping is crucial for tuning conjugated polymer electrical properties in organic optoelectronics.
• Conventional solution doping methods often degrade polymer crystalline order, hindering charge carrier mobility and device performance.

Purpose of the Study:

• To develop a crystalline structure-preserving doping strategy for conjugated polymers.
• To investigate the impact of loading-soaking doping (LSD) on polymer morphology and electrical properties compared to conventional methods.

Main Methods:

• Loading-soaking doping (LSD) strategy involving selective dopant localization in amorphous regions.
• Utilizing a F4TCNQ-cyclopentanone (CPO) complex for initial dopant distribution, followed by immersion in F4TCNQ-acetonitrile (ACN) solution.
• Characterization of polymer crystallinity, domain size, and molecular orientation before and after doping.

Main Results:

• LSD method successfully preserved the crystalline integrity of P3HT films, enhancing crystalline domain size from 104.3 Å to 121.7 Å.
• LSD-doped P3HT films achieved a conductivity of 66.8 S/cm, an 11-fold improvement compared to solution-mixed doping (SMD).
• SMD significantly disrupted polymer ordering, reducing domain size to 52.4 Å, while LSD maintained crystallinity and molecular orientation.

Conclusions:

• Loading-soaking doping (LSD) offers a superior alternative to conventional doping for enhancing charge transport in conjugated polymers.
• This strategy effectively optimizes dopant distribution, leading to high conductivity without compromising structural integrity.
• LSD presents a promising route for advancing high-performance organic optoelectronic devices.