Cu₂ZnSn(S,Se)₄ thin-films prepared from selenized nanocrystals ink

Area of Science:

• Materials Science
• Solid State Chemistry
• Renewable Energy

Background:

• Developing efficient and low-cost thin-film solar cells is crucial for renewable energy advancement.
• Copper Zinc Tin Sulfide (CZTS) is a promising material due to its earth-abundant and non-toxic nature.
• Optimizing CZTS film properties through synthesis and annealing is key to improving photovoltaic performance.

Purpose of the Study:

• To formulate CZTS ink using low-temperature synthesis of Nanocrystals (NCs).
• To investigate the effect of powder concentration on CZTS film properties.
• To examine the influence of selenization temperature on the structural, optical, and electrical properties of CZTSSe films for solar cell applications.

Main Methods:

• Low-temperature synthesis of CZTS Nanocrystals (NCs) and ink formulation.
• Fabrication of CZTS thin films and subsequent annealing under a selenium (Se)/argon (Ar) atmosphere at varying temperatures.
• Characterization using X-ray Diffraction (XRD) for structural analysis, UV-Vis spectroscopy for band gap determination, and Hall Effect measurements for electrical properties.

Main Results:

• Successful low-temperature synthesis of CZTS ink was achieved.
• Selenization led to a peak shift in XRD towards lower 2θ values, indicating Se incorporation and increased lattice parameters.
• Increasing selenization temperature enhanced grain size, reduced the band gap (1.52 to 1.05 eV), and improved carrier concentration and mobility. The film selenized at 550 °C showed the highest photoconductivity.

Conclusions:

• Low-temperature synthesis of CZTS NCs is feasible for creating printable inks.
• Selenization is an effective post-deposition treatment to improve CZTS film properties for photovoltaic applications.
• CZTSSe films selenized at 550 °C demonstrate significant potential for use in low-cost thin-film solar cells due to enhanced photoconductivity.