π-Conjugated Dipolar Structures: Synergistic Dipole Superposition for Cathode Modification toward Ohmic Contact and...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Cathode interfacial layers (CILs) are crucial for improving solar cell performance by minimizing Schottky barriers and enhancing built-in electric fields.
• Developing new CIL materials and understanding their mechanisms are vital for advancing solar cell technology.

Purpose of the Study:

• To investigate the design strategy of using dipole molecules as CILs.
• To explore how molecular design influences interfacial properties and device performance.

Main Methods:

• Designed four dipole molecules with varying anchoring groups and intramolecular dipole moments.
• Investigated the synergistic effects of intramolecular and interfacial dipoles.
• Evaluated the performance of these molecules as CILs in organic solar cells and as antisolvent additives in perovskite solar cells.

Main Results:

• The Rh-Py molecule significantly increased the interfacial dipole moment, strengthening the built-in electric field and optimizing ohmic contact in organic solar cells, achieving over 20% power conversion efficiency (PCE).
• Rh-Py effectively passivated Pb2+ defects in perovskite films due to strong interactions.
• As an antisolvent additive in perovskite solar cells, Rh-Py reduced nonradiative energy losses and enhanced open-circuit voltage, reaching a PCE of 25.80%.

Conclusions:

• Fully conjugated dipolar molecules represent a promising new class of interfacial layer materials.
• The demonstrated design principles offer a pathway for developing high-performance CILs for both organic and perovskite solar cells.