Improved Power Conversion Efficiency and Stability of Perovskite Solar Cells Induced by Surface Modification with...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) achieve high power conversion efficiencies (PCEs) exceeding 27%.
• Efficient charge extraction and minimized recombination depend on optimal interfaces between perovskite and hole transport layers (HTLs).
• Spiro-OMeTAD, a common HTL, requires doping (e.g., with Li-TFSI) to enhance conductivity but suffers from hygroscopicity, leading to device degradation.

Purpose of the Study:

• To address the stability issues of PSCs caused by hygroscopic dopants in HTLs.
• To enhance the perovskite/HTL interface for improved charge carrier dynamics and device longevity.
• To investigate the impact of interfacial molecular design on PSC efficiency and stability.

Main Methods:

• Modification of the perovskite/spiro-OMeTAD interface using two dipole molecules.
• Introduction of oxygen dipole (O-Dipole) molecules to improve band alignment and suppress trap states.
• Fabrication and characterization of modified PSCs for performance and stability assessment.

Main Results:

• The dipole molecules promoted effective band alignment at the perovskite/HTL interface.
• Oxygen dipoles successfully suppressed trap states, facilitating efficient hole extraction.
• The O-Dipole-modified PSCs exhibited enhanced efficiency and superior operational stability compared to control devices.

Conclusions:

• Interfacial molecular engineering is crucial for simultaneously boosting PSC efficiency and long-term stability.
• The use of O-Dipoles offers a promising strategy to overcome the limitations of conventional HTL doping.
• This work highlights the potential of tailored interfacial modification for advanced photovoltaic applications.