Poly(sulfobetaine methacrylate)s as electrode modifiers for inverted organic electronics.

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Organic electronic devices require precise control over electrode work functions for optimal performance.
• Existing work function modifiers often face challenges with processing compatibility and stability.

Purpose of the Study:

• To investigate poly(sulfobetaine methacrylate) (PSBMA) and its copolymers as solution-processable work function reducers.
• To evaluate the impact of PSBMA interlayers on the performance of inverted organic electronic devices.

Main Methods:

• Density functional theory calculations to determine the dipole moment of the sulfobetaine moiety.
• Fabrication of inverted organic electronic devices utilizing PSBMA interlayers.
• Characterization of work function reduction and device performance.

Main Results:

• PSBMA interlayers significantly reduced the work function of various electrodes (metals, graphene, PEDOT:PSS) by over 1 eV.
• An ultrathin PSBMA interlayer decreased the electron injection barrier between ITO and C70 by 0.67 eV.
• Substantial improvements in organic photovoltaic device performance were observed.

Conclusions:

• PSBMA offers a new class of dipole-rich, counterion-free, and pH-insensitive polymer interlayers.
• These interlayers are effective for enhancing electron injection and performance in inverted organic electronic devices.
• PSBMA's orthogonal solubility facilitates its integration into existing organic semiconductor processing workflows.