Constructing a Strongly Absorbing Low-Bandgap Polymer Acceptor for High-Performance All-Polymer Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• All-polymer solar cells (all-PSCs) exhibit excellent morphology stability for flexible applications.
• Current all-PSCs are limited by low power conversion efficiency (PCE) due to a lack of high-performance polymer acceptors.

Purpose of the Study:

• To synthesize a novel, high-performance polymer acceptor (PZ1) for all-PSCs.
• To improve the PCE of all-PSCs by addressing the limitations of existing polymer acceptors.

Main Methods:

• A new polymerization strategy was employed, embedding an acceptor-donor-acceptor building block into the polymer main chain to create PZ1.
• PZ1 was characterized for its optical and electronic properties, including band gap and absorption coefficient.
• All-PSCs were fabricated using a wide-band-gap polymer donor (PBDB-T) and the synthesized PZ1 acceptor.

Main Results:

• The synthesized polymer acceptor, PZ1, demonstrated broad absorption and a low band gap (1.55 eV) with a high absorption coefficient (1.3×10⁵ cm⁻¹).
• All-PSCs utilizing PBDB-T and PZ1 achieved a record-high PCE of 9.19% for all-polymer systems.
• The results highlight the effectiveness of the new polymerization strategy for developing efficient polymer acceptors.

Conclusions:

• The developed polymerization strategy successfully created a high-performance polymer acceptor (PZ1).
• This work sets a new benchmark for PCE in all-PSCs, demonstrating their potential as efficient and stable photovoltaic devices.
• The strategy offers a viable route for designing advanced polymer acceptors for next-generation solar cells.