Subtle Morphology Control with Binary Additives for High-Efficiency Non-Fullerene Acceptor Organic Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) performance is significantly influenced by the morphology of their active layers.
• Additives are commonly used to fine-tune this morphology and enhance device efficiency.

Purpose of the Study:

• To investigate the synergistic effect of a binary additive system, 1,8-diiodooctane (DIO) and 2,6-dimethoxynaphthalene (DMON), on the morphology and performance of PBDB-T:TTC8-O1-4F based OSCs.
• To compare the performance of binary additive systems with individual additives.

Main Methods:

• Fabrication of PBDB-T:TTC8-O1-4F based organic solar cells.
• Optimization of active layer morphology using a binary additive blend of DIO and DMON.
• Characterization of device performance, including power conversion efficiency (PCE), short-circuit current density (Jsc), and fill factor.

Main Results:

• The binary additive system achieved a power conversion efficiency (PCE) of 13.22%, outperforming individual additives (DIO: 12.05%, DMON: 11.19%).
• DIO promoted ordered packing of the TTC8-O1-4F acceptor, while DMON inhibited excessive donor-acceptor aggregation.
• The synergistic effect resulted in optimal phase separation and crystallite size, leading to enhanced Jsc (23.04 mA·cm-2) and fill factor (0.703).

Conclusions:

• The combined use of DIO and DMON offers a synergistic approach to optimize active layer morphology in PBDB-T:TTC8-O1-4F based OSCs.
• This binary additive strategy significantly enhances the performance of organic solar cells.
• The findings provide valuable insights for designing efficient additive systems for organic photovoltaic applications.