Constructing Chromium Multioxide Hole-Selective Heterojunction for High-Performance Perovskite Solar Cells.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) face efficiency limitations due to nonradiative recombination at the perovskite/charge transport layer interface.
• Optimizing heterojunctions is crucial for enhancing PSC performance and stability.

Purpose of the Study:

• To develop a novel hole-selective heterojunction for PSCs using solution-processed chromium multioxide (CrO_x).
• To investigate the impact of CrO_x on defect reduction and charge transport dynamics.

Main Methods:

• Fabrication of MAPbI₃/CrO_x/Spiro-OMeTAD heterojunctions.
• Characterization of material properties and device performance.
• Analysis of recombination mechanisms and charge carrier dynamics.

Main Results:

• The CrO_x layer effectively passivates defect sites at the perovskite contact through a redox shuttle mechanism.
• CrO_x reduces the valence band maximum (VBM)-HOMO offset, minimizing thermionic losses and improving hole collection.
• Achieved a power conversion efficiency of 21.21%, a significant improvement over the control device (18.46%).
• Demonstrated excellent device stability.

Conclusions:

• Solution-processed CrO_x is a promising material for constructing efficient and stable hole-selective heterojunctions in PSCs.
• The CrO_x interlayer effectively suppresses recombination losses at the heterojunction.
• This work offers new strategies for advancing PSC technology through rational interface engineering.