Cesium Doping for Performance Improvement of Lead(II)-acetate-Based Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Organolead trihalide perovskite materials are crucial for next-generation solar cells.
• Lead(II)-acetate (Pb(Ac)₂) offers an alternative lead source, simplifying perovskite film fabrication by eliminating anti-solvent treatment.
• Cesium (Cs) doping is explored as a strategy to further enhance perovskite solar cell performance.

Purpose of the Study:

• To investigate the impact of cesium doping on the structural and optoelectronic properties of CH₃NH₃PbI₃ perovskite films.
• To evaluate the performance enhancement of Pb(Ac)₂-based perovskite solar cells (PSCs) upon cesium incorporation.
• To determine the optimal cesium doping concentration for maximizing power conversion efficiency (PCE) and device stability.

Main Methods:

• Fabrication of CH₃NH₃PbI₃ perovskite films using lead(II)-acetate as the lead precursor.
• Introduction of cesium ions into the perovskite lattice at a concentration of 5 mol%.
• Characterization of perovskite film morphology, crystallinity, and defect density using techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM).
• Fabrication and testing of perovskite solar cell devices to measure key performance parameters including open-circuit voltage, short-circuit current density, fill factor, and PCE.

Main Results:

• Cesium doping at 5 mol% significantly improved the crystallinity of the CH₃NH₃PbI₃ perovskite film.
• Doping led to a reduction in surface pinholes, resulting in a more uniform and higher-quality perovskite layer.
• Average power conversion efficiency (PCE) of the PSCs increased from 14.1% to 15.57%.
• The enhanced PCE was primarily attributed to improvements in short-circuit current density and fill factor.
• A champion device achieved a PCE of 18.02% with negligible hysteresis and demonstrated stable power output.

Conclusions:

• Cesium doping is an effective strategy for enhancing the performance of Pb(Ac)₂-based perovskite solar cells.
• Improved film quality, characterized by increased crystallinity and reduced defects, is key to the observed performance gains.
• The use of lead(II)-acetate combined with cesium doping presents a viable pathway for developing efficient and stable perovskite solar technologies.