Perovskite/Hole Transport Layer Interface Improvement by Solvent Engineering of Spiro-OMeTAD Precursor Solution

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) show great promise for energy conversion due to high efficiency and low cost.
• Improving power conversion efficiency (PCE) requires effective interfacial engineering to minimize trap states and carrier transport barriers.

Purpose of the Study:

• To develop a facile method for enhancing the interface between the perovskite absorber and hole transport layers (HTLs) in PSCs.
• To investigate the impact of adding acetonitrile (ACN) to the Spiro-OMeTAD precursor solution on PSC performance.

Main Methods:

• A small amount of acetonitrile (ACN) was incorporated into the Spiro-OMeTAD precursor solution.
• The ACN treatment modified the interface by dissolving the perovskite surface, creating an interdiffusion structure with the HTL.
• Fabricated PSCs were characterized to evaluate their performance, including PCE and hysteresis.

Main Results:

• The ACN treatment facilitated interdiffusion between the perovskite and Spiro-OMeTAD layers, improving electrical contact.
• Enhanced hole collection and reduced recombination losses were observed at the modified interface.
• Optimized PSCs achieved a maximum PCE of 19.7% and a steady-state PCE of 19.0% with low hysteresis.

Conclusions:

• A simple ACN addition to the HTL precursor is an effective strategy for interfacial engineering in PSCs.
• This method significantly enhances charge transport and reduces recombination, leading to improved device efficiency.
• The findings offer a promising route for fabricating high-performance and stable perovskite solar cells.