Dipole Molecule-Mediated Modulating Residual PbI₂ Clusters in Two-Step-Processing Inverted Perovskite Photovoltaics

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Two-step perovskite solar cell fabrication often leaves unreacted lead iodide (PbI2) at interfaces.
• Unreacted PbI2 creates defect states, hindering device performance and stability.
• Key defects include Pb0, vacancies of iodide (VI), and vacancies of formamidinium (VFA).

Purpose of the Study:

• To investigate the impact of 3-(decyldimethylammonio)propane sulfonate inner salt (3DPSI) predeposition on perovskite solar cells.
• To understand how 3DPSI modulates PbI2 and mitigates defect formation.
• To enhance the power conversion efficiency and operational stability of perovskite photovoltaics.

Main Methods:

• Strategic predeposition of the dipole molecule 3DPSI.
• Utilizing the two-step fabrication method for inverted perovskite solar cells.
• Combining experimental characterization with theoretical analysis.

Main Results:

• Effective regulation of residual PbI2 clusters and suppression of derivative defects (Pb0, VI, VFA).
• Significant enhancement in perovskite crystal quality.
• Achieved a power conversion efficiency of 24.62% in two-step-processed inverted perovskite solar cells.
• Demonstrated improved stability under continuous illumination.

Conclusions:

• Predeposition of 3DPSI is a viable strategy to improve perovskite solar cell performance.
• 3DPSI effectively passivates defects originating from unreacted PbI2.
• This approach offers a pathway to highly efficient and stable perovskite photovoltaic devices.