Simple approach for an electron extraction layer in an all-vacuum processed n-i-p perovskite solar cell

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Scalable fabrication of perovskite solar cells (PSCs) often utilizes vacuum processing.
• The n-i-p PSC structure is less common than p-i-n due to challenges in vacuum-depositing efficient electron extraction layers (EELs) on indium tin oxide (ITO).
• Alternative EEL solutions are needed for vacuum-processed n-i-p PSCs in specific applications.

Purpose of the Study:

• To develop an efficient vacuum-deposited EEL for n-i-p perovskite solar cells.
• To investigate the performance enhancement of PSCs using a novel C60:BCP mixed EEL.
• To explore alternative strategies for n-type contacts in vacuum-processed PSCs.

Main Methods:

• Fabrication of an electron extraction layer (EEL) using a co-sublimation technique with C60 and bathocuproine (BCP).
• Integration of the C60:BCP EEL into an all-vacuum processed n-i-p perovskite solar cell architecture.
• Characterization of device performance, focusing on power conversion efficiency (PCE).

Main Results:

• An efficient vacuum-deposited EEL composed of a C60:BCP mixture was successfully developed.
• Incorporation of BCP into C60 did not result in conventional n-doping but enhanced charge extraction.
• Power conversion efficiency (PCE) of all-vacuum processed PSCs increased from 13.1% to 18.1% using the C60:BCP EEL.
• The C60:BCP film likely achieves better energy level alignment with electrodes, improving charge extraction.

Conclusions:

• A C60:BCP mixed film serves as an effective electron extraction layer for vacuum-processed n-i-p perovskite solar cells.
• This approach offers a viable alternative for fabricating n-i-p PSCs using vacuum thermal evaporation.
• The enhanced charge extraction and improved PCE demonstrate the potential of this novel EEL for scalable PSC production.