Donor-Acceptor-Type S,N-Heteroacene-Based Hole-Transporting Materials for Efficient Perovskite Solar Cells

Area of Science:

• Materials Science
• Photovoltaics
• Organic Electronics

Background:

• Perovskite solar cells (PSCs) are a promising next-generation photovoltaic technology.
• Efficient hole-transporting materials (HTMs) are crucial for optimizing PSC performance.
• Developing novel HTMs with suitable energy levels and charge transport properties is essential.

Purpose of the Study:

• To synthesize and characterize two new donor-acceptor (D-A)-substituted S,N-heteroacene-based molecules.
• To evaluate their performance as hole-transporting materials (HTMs) in perovskite solar cells (PSCs).
• To investigate the structure-property relationships governing their optoelectronic behavior in PSCs.

Main Methods:

• Synthesis of novel D-A substituted S,N-heteroacene molecules (HTM-1 and HTM-2).
• Optical and electrochemical characterization to determine energy levels.
• Fabrication and testing of PSC devices incorporating the synthesized HTMs.
• Time-resolved photoluminescence spectroscopy to study charge carrier dynamics.

Main Results:

• The synthesized HTMs possess suitable energy levels for efficient use in PSCs.
• PSCs utilizing HTM-1 and HTM-2 achieved power-conversion efficiencies of 17.7% and 16.1%, respectively.
• Analysis revealed favorable optoelectronic properties, including conductivity and charge carrier recombination characteristics.
• Hole injection efficiency correlates with the highest occupied molecular orbital (HOMO) levels, as confirmed by time-resolved photoluminescence.

Conclusions:

• The novel S,N-heteroacene-based molecules demonstrate significant potential as effective HTMs for PSCs.
• The D-A substitution strategy is viable for tuning the electronic properties of heteroacene co-oligomers.
• These findings pave the way for the development of advanced HTMs for high-performance perovskite solar cells.