Multi-Functional Solid Additive Induced Favorable Vertical Phase Separation and Ordered Molecular Packing for Highly...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Layer-by-layer (LBL) deposition is promising for organic photovoltaic (OPV) cells due to controlled vertical phase distribution.
• Solid additives are rarely used to fine-tune LBL film morphology for improved OPV efficiency and stability.

Purpose of the Study:

• To achieve hierarchical morphology control in LBL OPV devices using a dual functional solid additive.
• To investigate the distinct roles of the additive in donor and acceptor layers for optimizing OPV performance.

Main Methods:

• Fabrication of LBL OPV devices with a dual functional solid additive.
• Systematic introduction of the additive into donor and/or acceptor layers.
• Morphological characterization and device performance analysis.

Main Results:

• Additive in the donor layer promoted favorable vertical component distribution.
• Additive in the acceptor layer enhanced molecular crystallinity and charge transport.
• Optimized LBL devices achieved high power conversion efficiencies (PCEs) of 16.4% (binary) and 17.4% (quaternary).

Conclusions:

• A dual functional solid additive effectively controls morphology in LBL OPV films.
• This strategy enhances both vertical phase distribution and molecular crystallinity.
• The method offers a new pathway for developing high-efficiency and stable LBL OPV cells.