Transfer-Printed Cuprous Iodide (CuI) Hole Transporting Layer for Low Temperature Processed Perovskite Solar Cells.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) show high efficiency but rely on expensive doped spiro-OMeTAD hole transport layers (HTLs).
• Doping in HTLs presents processing and performance challenges, hindering commercialization.
• There is a critical need for cost-effective, dopant-free HTLs for PSCs.

Purpose of the Study:

• To develop and evaluate a low-cost, dopant-free hole transport material for n-i-p perovskite solar cells (PSCs).
• To investigate the use of cuprous iodide (CuI) as an HTL fabricated via a novel transfer-printing technique.
• To incorporate a low-temperature processed electron transport layer (ETL) for improved device fabrication.

Main Methods:

• Fabrication of n-i-p PSCs using cuprous iodide (CuI) as the hole transport layer (HTL).
• Utilized a novel transfer-printing technique to deposit CuI, avoiding solvent interactions with the perovskite layer.
• Incorporated tin oxide (SnO2) as the electron transport layer (ETL) for reduced processing temperatures.

Main Results:

• PSCs fabricated at 80 °C with a 20 nm CuI HTL achieved a power conversion efficiency of 8.3%.
• Key performance metrics included a short-circuit current density (JSC) of 19.3 mA/cm² and a fill factor (FF) of 53.8%.
• The achieved efficiency is comparable to undoped spiro-OMeTAD PSCs and represents the highest for ambient-fabricated PSCs using CuI HTL.

Conclusions:

• Cuprous iodide (CuI) is a viable, low-cost, dopant-free HTL for ambient-processed PSCs.
• The novel transfer-printing method and SnO2 ETL enable efficient PSC fabrication at reduced temperatures.
• This approach offers a promising pathway towards the commercialization of efficient and affordable perovskite solar cells.