Pristine Poly( para-phenylene): Relating Semiconducting Behavior to Kinetics of Precursor Conversion

Area of Science:

• Materials Science
• Polymer Chemistry
• Organic Electronics

Background:

• Poly(para-phenylene) (PPP) is a highly sought-after conjugated polymer semiconductor.
• Its synthesis has been challenging due to solubility issues.

Purpose of the Study:

• To synthesize unsubstituted poly(para-phenylene) (PPP) as a prototype conjugated polymer semiconductor.
• To investigate the conversion process and its effect on semiconducting properties.

Main Methods:

• Thermal aromatization of a precursor polymer.
• Infrared (IR) spectroscopy and Vis ellipsometry for conversion analysis.
• Thin-film transistor (TFT) device fabrication and characterization.
• Molybdenum trioxide (MoO3) p-doping for further validation.

Main Results:

• The conversion rate of the precursor to PPP is temperature-dependent and inversely related to film density.
• Higher conversion degrees correlate with improved p-type semiconducting properties in PPP films.
• Semiconducting behavior was confirmed through transistor measurements and IR spectroscopy.

Conclusions:

• Unsubstituted poly(para-phenylene) (PPP) can be successfully synthesized via thermal aromatization.
• The study provides insights into controlling PPP's semiconducting properties through synthesis conditions.
• The findings pave the way for utilizing PPP in organic electronic applications.