Low Band Gap Perovskite Concentrator Solar Cells: Physics, Device Simulation, and Experiment

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) demonstrate high power conversion efficiencies (PCEs).
• Concentrated perovskite solar cells (PCSCs) exhibit significantly lower performance compared to standard PSCs.
• Understanding energy losses in PCSCs under high illumination is crucial for performance improvement.

Purpose of the Study:

• To investigate the optoelectronic mechanisms and energy loss factors in low band gap Sn-Pb PCSCs under varying light concentrations.
• To identify the primary limitations hindering PCSC performance enhancement.
• To provide insights for optimizing PCSC design and fabrication.

Main Methods:

• Device-level optoelectronic simulation of Sn-Pb PCSCs under different illumination intensities.
• Analysis of electromagnetic and carrier-transport processes within the device.
• Electrical manipulation of the perovskite layer and hole transport layer (HTL).
• Fabrication and characterization of optimized low band gap PCSCs.

Main Results:

• Increased bulk recombination, primarily due to the hole transport layer's limited hole transport/collection capability, was identified as the main performance limiter in PCSCs.
• Electrical manipulation of the perovskite layer and HTL significantly improved carrier transport capabilities.
• Optimized low band gap PCSCs achieved high PCEs of up to 22.36% under 4.17 sun concentration.

Conclusions:

• The study elucidates the critical role of carrier transport, particularly hole transport, in the performance of PCSCs under concentrated light.
• Targeted improvements in the HTL and perovskite layer are essential for overcoming recombination losses and enhancing PCSC efficiency.
• The findings pave the way for developing high-performance PCSCs for solar energy applications.