Low-Dimensional Hetero-Interlayer Enabling Sub-Bandgap Photovoltaic Conversion for Perovskite Solar Cells

Area of Science:

• Materials Science
• Photovoltaics
• Nanotechnology

Background:

• Perovskite solar cells (PSCs) face theoretical efficiency limits due to energy loss.
• Sub-band gap photovoltaic conversion is a strategy to enhance energy harvesting in PSCs.
• Low-dimensional materials offer potential for improved PSC performance.

Purpose of the Study:

• To develop a sensitizer for sub-band gap photovoltaic conversion in PSCs.
• To enhance the power conversion efficiency (PCE) and operational stability of PSCs.
• To investigate the mechanism of near-infrared region gain using organic metal halides.

Main Methods:

• Synthesis of a zero-dimensional organic metal halide based on hydroxyquinoline (HQ).
• Incorporation of HQ into PSCs to sensitize for near-infrared light absorption.
• Transient absorption spectroscopy to confirm energy transfer and sub-band gap photocurrent generation.

Main Results:

• The developed HQ-based material ([ZnI4]2- skeleton) facilitated singlet-to-triplet state transitions.
• Efficient energy transfer from HQ to perovskite was observed, exciting additional electron-hole pairs.
• The HQ2ZnI4 material improved electronic and crystal structure, optimizing energy levels and acting as a protective layer.
• Considerable PCEs were achieved in both small and large-area devices with excellent operational stability.

Conclusions:

• The novel HQ-based material enables effective sub-band gap photovoltaic conversion in PSCs.
• This strategy enhances light management and expands the application of low-dimensional materials in photovoltaics.
• The low-cost approach offers a promising route for advancing PSC technology.