Perylene-Diimide Dimers with Cross Conformations as Cathode Interfacial Layers for High-Performance and Stable...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Perylene-diimide (PDI)-based materials are effective cathode interfacial layers (CILs) in organic solar cells (OSCs).
• Existing PDI monomers suffer from high crystallinity, and copolymers exhibit poor batch-to-batch repeatability, hindering their application.

Purpose of the Study:

• To design and synthesize novel PDI-based homo-oligomers, specifically single-bond-linked perylene-diimide dimers (S-di(PDI)s).
• To investigate the impact of these S-di(PDI)s as CILs in OSCs and perovskite solar cells (PSCs).

Main Methods:

• Synthesis of S-di(PDI)s with a cross conformation between PDI units.
• Fabrication of OSCs using D18:L8-BO active layers with S-di(PDI)-NBr as CIL.
• Fabrication of PSCs using S-di(PDI)-NBr as CIL.

Main Results:

• S-di(PDI)s retain the conjugated backbone of PDI while reducing aggregation through a cross conformation.
• OSCs with S-di(PDI)-NBr CIL achieved a power conversion efficiency (PCE) of 20.53%, surpassing devices with PNDIT-F3N.
• PSCs with S-di(PDI)-NBr CIL achieved a PCE of 26.53%, outperforming those with C$_{60}$ CIL.

Conclusions:

• S-di(PDI)s offer improved electron transport, optical, and thermal stability compared to PDI monomers.
• The novel S-di(PDI)s represent a promising alternative to existing CILs for high-performance OSCs and PSCs.