Unfused Electronic Acceptor-Based Polymers as Interfacial Materials for Efficient Inverted Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Surface trap states at the interface between the perovskite active layer and electron transporting layer (ETL) hinder the performance of inverted perovskite solar cells (PSCs).
• Developing efficient interfacial materials is crucial for overcoming these limitations and advancing PSC technology.

Purpose of the Study:

• To design and synthesize novel unfused electronic acceptor-based polymers (PC-1-PC-3) as interfacial materials for inverted PSCs.
• To investigate the effect of tailored alkyl groups on polymer performance.
• To improve the interface contact and reduce trap states in inverted PSCs.

Main Methods:

• Synthesis of three unfused electronic acceptor-based polymers (PC-1-PC-3) with varying alkyl groups.
• Fabrication of inverted PSC devices incorporating these polymers as interfacial layers.
• Characterization of device performance, including short-circuit current density, fill factor, power conversion efficiency, and hysteresis.

Main Results:

• The polymer PC-2 demonstrated superior performance due to faster interfacial charge extraction and more efficient trap state passivation.
• Devices incorporating PC-2 achieved a high short-circuit current density of 22.49 mA cm⁻², a fill factor of 0.821, and a maximum power conversion efficiency of 20.50%.
• PC-2 based devices exhibited negligible hysteresis and outperformed PC-1, PC-3, and reference devices.

Conclusions:

• Unfused electronic acceptor-based polymers, particularly PC-2, are effective interfacial materials for enhancing the performance of inverted PSCs.
• Tailoring alkyl groups on these polymers is a viable strategy for optimizing interfacial properties.
• This research offers valuable insights for the molecular design of future high-performance interfacial materials for perovskite solar cells.