Long-Term Stable Recombination Layer for Tandem Polymer Solar Cells Using Self-Doped Conducting Polymers

Area of Science:

• Materials Science
• Renewable Energy
• Polymer Chemistry

Background:

• Tandem polymer solar cells (PSCs) commonly use poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a recombination layer (RL).
• The acidic nature of PEDOT:PSS derived from its insulating component significantly limits the operational lifetime of PSCs.
• Developing alternative, stable RLs is crucial for advancing PSC technology.

Purpose of the Study:

• To demonstrate efficient and stable tandem PSCs by introducing an acid-free self-doped conducting polymer (SCP) and zinc oxide nanoparticles (ZnO NPs) as a novel RL.
• To create PSS-free tandem PSCs with enhanced performance and longevity.
• To investigate the synergistic effects of SCP and p-type conjugated polyelectrolyte (p-CPE) in a nanocomposite RL.

Main Methods:

• Fabrication of a novel nanocomposite recombination layer using an acid-free self-doped conducting polymer (SCP) and a p-type conjugated polyelectrolyte (p-CPE).
• Integration of SCP and p-CPE into the tandem PSC structure to form a self-organized recombination layer.
• Characterization of the electrical properties, charge transport, and work function modification of the novel RL.

Main Results:

• The novel RL, composed of SCP and p-CPE, exhibited extremely low electrical resistance and ohmic contact properties.
• The nanocomposite RL facilitated efficient charge transport and recombination, leading to nearly loss-free charge collection.
• Tandem PSCs utilizing the new RL achieved a high power conversion efficiency of 10.2% and demonstrated a prolonged operational lifetime.

Conclusions:

• The developed acid-free SCP-based RL offers a promising strategy for enhancing the efficiency and stability of tandem PSCs.
• The synergistic combination of SCP and p-CPE in the RL provides a versatile approach for optimizing charge collection and device performance.
• This work provides new insights for designing advanced recombination layers and expands the potential applications of SCPs in electronic devices.