Kesterite Cu2ZnSnS4 as a Low-Cost Inorganic Hole-Transporting Material for High-Efficiency Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Kesterite-structured Copper Zinc Tin Sulfide (CZTS) is a quaternary semiconductor with an optimal bandgap for light absorption.
• CZTS is known for its earth-abundant elements and high absorption coefficient, making it suitable for solar cell applications.
• Organo-lead halide perovskite solar cells (PSCs) commonly use organic hole transporting materials (HTMs) like spiro-MeOTAD.

Purpose of the Study:

• To investigate the potential of CZTS nanoparticles as a novel inorganic hole transporting material (HTM) in PSCs.
• To optimize the size and incorporation conditions of CZTS nanoparticles as an HTM.
• To compare the performance and interfacial properties of CZTS HTM with the conventional spiro-MeOTAD HTM.

Main Methods:

• Application of CZTS nanoparticles as an inorganic HTM in PSCs.
• Optimization of CZTS nanoparticle size and incorporation.
• Investigation of optical absorption, crystallinity, and morphology of perovskite films with CZTS HTM.
• Analysis of the perovskite/Au electrode interface and charge recombination.

Main Results:

• Achieved a power conversion efficiency (PCE) of 12.75% for PSCs using CZTS nanoparticles as HTM.
• This PCE is the highest reported for PSCs with Cu-based inorganic HTMs and comparable to spiro-MeOTAD.
• CZTS HTM demonstrated efficient hole transport and suppressed charge recombination at the perovskite/Au electrode interface.

Conclusions:

• CZTS nanoparticles are effective as a low-cost inorganic HTM in PSCs, rivaling organic HTMs like spiro-MeOTAD.
• This work establishes a new role for CZTS in photovoltaics as a hole conductor, expanding its application beyond light absorption.
• The findings pave the way for developing more efficient and cost-effective perovskite solar cells.