In Situ Buried Interface Engineering towards Printable Pb-Sn Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• High-efficiency lead-tin narrow-bandgap perovskite solar cells (PSCs) commonly use PEDOT:PSS as a hole-transport layer (HTL).
• The shallow work function of PEDOT:PSS leads to significant minority carrier recombination at the perovskite/HTL interface, limiting device performance.

Purpose of the Study:

• To address the limitations of PEDOT:PSS in PSCs by suppressing nonradiative recombination at the perovskite/HTL interface.
• To enhance the efficiency and open-circuit voltage (V_OC) of lead-tin PSCs through in situ interface engineering.

Main Methods:

• An in situ interface engineering strategy was employed using 2-fluoro benzylammonium iodide (FBI) to modify the PEDOT:PSS HTL.
• The work function (W_F) of PEDOT:PSS was measured before and after FBI modification.
• The performance of modified PSCs was evaluated, including power conversion efficiency and V_OC.

Main Results:

• FBI modification increased the work function of PEDOT:PSS by 0.1 eV.
• Lead-tin PSCs with FBI modification achieved a power conversion efficiency of 20.5% and a V_OC of 0.843 V.
• The strategy was successfully applied to blade-coated PSCs, yielding 18.3% efficiency and a V_OC of 0.845 V.

Conclusions:

• In situ interface modification with FBI effectively suppresses nonradiative recombination at the perovskite/HTL interface.
• FBI is a promising strategy for enhancing the performance of lead-tin PSCs, particularly for scalable fabrication methods like blade coating.