Chemical and Morphological Control of Interfacial Self-Doping for Efficient Organic Electronics

Area of Science:

• Organic electronics
• Materials science
• Photovoltaics

Background:

• Solution-based processing for electrical doping is key to enhancing organic electronic devices.
• Current methods for doping organic semiconductor interfaces can be complex.
• Multilayer organic electronic devices require efficient interfacial engineering.

Purpose of the Study:

• To develop a simplified solution-based method for electrical doping of organic semiconductor interfaces.
• To synthesize self-doping perylene diimide (PDI)-based ionene polymers for this purpose.
• To improve the efficiency of organic photovoltaic devices (OPVs) through novel interfacial interlayers.

Main Methods:

• Synthesis of PDI-based ionene polymers with embedded electrolyte dopants.
• Incorporation of functional groups in PDI monomers to suppress aggregation.
• Solution processing of self-doping interlayers into organic photovoltaic devices (OPVs).

Main Results:

• Achieved significant increases in power conversion efficiency (PCE) for fullerene-based OPVs (2.62% to 10.64%) and nonfullerene-based OPVs (3.34% to 10.59%).
• Demonstrated controllable thickness and chemical/morphological properties of the self-doping interlayers.
• Confirmed PCEs exceeding 9% for both types of OPVs with interlayers ranging from 3 to 40 nm.

Conclusions:

• PDI-ionene interlayers enable efficient interfacial doping and conductivity control.
• Conductive channels within doped organic semiconductor films are crucial for charge transport.
• This approach offers a promising route to high-performance, solution-processed organic electronic devices.