Solution-Processable Cu₃BiS₃ Thin Films: Growth Process Insights and Increased Charge Generation Properties by...

Area of Science:

• Materials Science
• Solid State Chemistry
• Photovoltaics

Background:

• Copper bismuth sulfide (Cu₃BiS₃) is a promising material for photovoltaic devices due to its optical properties.
• Efficient fabrication methods are crucial for developing Cu₃BiS₃-based solar cells.

Purpose of the Study:

• To fabricate Cu₃BiS₃ thin films using a spin-coating method.
• To investigate the impact of an indium sulfide (In₂S₃) interlayer on the performance of TiO₂/Cu₃BiS₃ heterojunctions for photovoltaic applications.

Main Methods:

• Spin coating of copper and bismuth xanthate precursor solutions.
• Annealing at 300 °C to form Cu₃BiS₃ films.
• Time-resolved simultaneous small and wide-angle X-ray scattering (TR-SAXS/WAXS) for film formation analysis.
• Transient absorption spectroscopy (TAS) for charge carrier dynamics.

Main Results:

• Cu₃BiS₃ films exhibit a high absorption coefficient and a band gap of 1.55 eV.
• TR-SAXS/WAXS provided insights into the film formation process.
• Introduction of an In₂S₃ interlayer significantly enhanced charge generation yields in TiO₂/Cu₃BiS₃ heterojunctions.
• Long-lived charge carriers with a t_50% of 10 μs were observed.

Conclusions:

• The developed method enables the fabrication of high-quality Cu₃BiS₃ thin films suitable for photovoltaics.
• The In₂S₃ interlayer is effective in improving charge carrier dynamics and device performance.
• Cu₃BiS₃-based heterojunctions show potential for efficient solar energy conversion.