A Gradient Heterostructure Based on Tolerance Factor in High-Performance Perovskite Solar Cells with 0.84 Fill Factor

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Gradient heterostructures are crucial for controlling charge flow in perovskite solar cells (PSCs).
• Traditional methods like diffusion are time-consuming, costly, and create gradients on only one side of the film.

Purpose of the Study:

• To develop a novel, efficient method for creating spontaneous gradient heterostructures in PSCs.
• To improve charge separation and collection in perovskite thin films.
• To enhance the overall efficiency and performance of perovskite solar cells.

Main Methods:

• Utilized "intolerant" n-type heteroatoms (Sb³⁺, In³⁺) with mismatched properties to induce spontaneous enrichment on both sides of perovskite films.
• Employed theoretical calculations and experimental observations to analyze the resulting band structure and interfacial electronic hybridization.
• Integrated the modified perovskite films into solar cell devices, extracting dopants using a standard hole-transport layer.

Main Results:

• Successfully fabricated perovskite thin films with spontaneous graded heterojunctions on both sides.
• Demonstrated optimized charge management due to tailored band structure and interfacial electronic hybridization.
• Achieved a champion perovskite solar cell with a stabilized power conversion efficiency of 21.04%, a high fill factor of 0.84, and minimal hysteresis.

Conclusions:

• The spontaneous enrichment strategy offers a cost-effective and efficient alternative to traditional gradient heterostructure fabrication.
• The optimized charge separation and collection significantly boost PSC performance.
• This method paves the way for highly efficient and stable perovskite solar cells.