Dual-Path Optimization Strategy for High-Efficiency Chalcogenide Perovskite Solar Cells: Bulk Bandgap Engineering and...

Area of Science:

• Materials Science
• Solid-State Physics
• Photovoltaics

Background:

• Chalcogenide perovskites present a stable, high-performance alternative to hybrid perovskites.
• The optoelectronic potential of their tunable bandgap is currently underutilized.
• Developing efficient and stable solar cells requires advanced material design.

Purpose of the Study:

• To introduce a dual-path optimization strategy for lead-free BaZr$_{1-x}$Ti$_{x}$S$_{3}$ chalcogenide perovskites.
• To synergistically combine a compositionally graded bandgap with advanced interfacial design and a WS$_{2}$ electron transport layer (ETL).
• To unlock the full optoelectronic potential of these materials for high-efficiency photovoltaics.

Main Methods:

• Implementation of a compositionally graded bandgap in BaZr$_{1-x}$Ti$_{x}$S$_{3}$ using a β-function profile (x: 0-0.6).
• Integration of a WS$_{2}$ ETL for advanced interfacial design.
• Utilizing Solar Cell Capacitance Simulator - One Dimension (SCAPS-1D) for performance simulations under AM1.5G illumination.

Main Results:

• Precise control of the Zr/Ti compositional gradient established a continuous internal energy field, enhancing broadband photon harvesting and charge separation.
• The WS$_{2}$ ETL suppressed interfacial recombination and facilitated efficient charge extraction, reducing charge loss.
• Simulations predicted a power conversion efficiency (PCE) of 24.22% for the co-optimized architecture.

Conclusions:

• Coordinated optimization of the absorber's electronic landscape and charge-selective contacts is crucial for high-efficiency perovskite-inspired materials.
• The dual-path strategy provides a holistic design framework for next-generation photovoltaics.
• This approach demonstrates the potential of chalcogenide perovskites as stable and efficient solar cell materials.