Reversible Dopant-Induced Cross-Linking of Semiconducting Polymer Films for Sequential Multilayer Deposition.

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Sequential multilayer processing is crucial for fabricating advanced semiconducting polymer (SP) devices like organic photovoltaics (OPVs).
• Optimizing charge transport in SP devices requires minimizing the energy gap between transport layers and electrodes.
• Planar heterojunctions offer superior control over interfaces and directional charge transport compared to bulk heterojunctions.

Purpose of the Study:

• To develop a universally applicable, solution-based method for creating multilayered semiconducting polymers (SPs).
• To enable the fabrication of unmixed planar heterojunctions in SP devices.
• To enhance the mechanical and thermal stability of multilayered organic electronic devices.

Main Methods:

• Sequential deposition of semiconducting polymer (SP) films from solution.
• Temporary cross-linking of the underlayer using sequentially deposited molecular dopants to induce insolubility.
• Deposition of a second SP film followed by quantitative dedoping to remove the molecular dopant.

Main Results:

• Demonstrated a reliable method for preparing bilayers of unaltered SPs, forming unmixed planar heterojunctions.
• Successfully fabricated p/n, p/p, n/p, and n/n bilayers using various molecular dopants and SPs.
• The processing method is material-universal, easy to implement, reliable, and reproducible.

Conclusions:

• This novel multilayer processing technique offers a versatile approach for fabricating organic electronic devices.
• The method's ease, reliability, and material universality make it highly valuable for advancing organic electronics research.
• It enables precise control over interfaces, leading to improved device performance and stability.