Invariant Charge Carrier Dynamics Using a Non-Planar Non-Fullerene Acceptor across Multiple Processing Solvents

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Conventional non-fullerene acceptors (NFAs) often feature planar structures for efficient electron mobility in organic photovoltaic devices.
• Agrivoltaics, particularly green-absorbing applications, require optimized organic photovoltaic materials.

Purpose of the Study:

• To investigate a non-planar A-D-A'-D-A type NFA designed for poly(3-hexylthiophene-2,5-diyl) (P3HT) in green-absorbing agrivoltaic applications.
• To understand the impact of NFA non-planarity on charge carrier dynamics and morphological tolerance.

Main Methods:

• Microsecond transient absorption spectroscopy
• Atomic force microscopy
• Photoluminescence spectroscopy
• Raman spectroscopy
• Computational studies

Main Results:

• Charge carrier decay dynamics remained relatively invariant across different processing solvents for the blend films.
• Raman spectroscopy and computational studies confirmed the non-planar structure of the NFA with multiple conformations present.
• The crystalline nature of P3HT was preserved, while the NFA's non-planarity created a dispersive acceptor environment.
• High tolerance to morphological variation was observed, irrespective of the processing solvent used.

Conclusions:

• The non-planarity of NFAs is a key factor in achieving stable charge carrier decay dynamics and morphological tolerance in organic photovoltaic devices.
• Non-planar materials show significant potential as acceptors in organic photovoltaics, offering advantages over traditional planar designs.
• This study highlights a promising molecular design strategy for efficient and robust organic photovoltaic applications, including agrivoltaics.