Sulfurization temperature effects on crystallization and performance of superstrate CZTS solar cells

Abstract

Kesterite materials based on Cu2ZnSnS4 composition are considered as promising absorber material for the next generation of photovoltaics due to raw materials abundance and low toxicity. Developing a superstrate architecture using kesterite as an absorber could be the key to a better performance, which allows new ways of engineering the formation of a kesterite thin film. In this work, we study the effects of the sulfurization temperature on the crystallization of kesterite film when is fabricated in a superstrate architecture, and how this affects the performance of a solar cell. We noted that the temperature affects the final composition of the absorber due to cadmium diffusion at 500 ºC from the CdS layer, while the temperature above 530 ºC is essential for a complete Zn incorporation into the crystal structure. The crystallinity is highly affected, and a temperature of 550 ºC is found to be favorable for the crystal growth, and the fabricated device gave improved performance. Impedance spectroscopy measurements suggest the performance enhancement is due to the reduction of defects and an increase of the depletion width in the p-n junction.

Molecular Tailoring of Pyridine Core-Based Hole Selective Layer for Lead Free Double Perovskite Solar Cells Fabrication

“…Impedance and capacitance–voltage measurements were performed inside a Faraday box with a Biologic impedance analyzer, following the reported literature, , by applying a 20 mV perturbation in a frequency range from 1 GHz to 100 Hz, and applied constant voltage from −0.5 to 1.5 V. EC-lab software was used to fit the equivalent circuits.…”

Overcoming Limitations in Water–Ethanol Sprayed Superstrate Solar Cells by Compositional Engineering of Cu2CdSn(S,Se)4

“…However, typical electron selective layers (ETL), such as CdS, have low compatibility with CZTS in a superstrate architecture. 21 Here, a compact or nanostructured thin film of TiO 2 can be adopted as ETL. 22 TiO 2 can act as a stable and protective layer for the FTO while also reducing the risk of shunt paths.…”

“…In a superstrate architecture, a wide variety of materials can be tested as a hole transport layer (HTL) and back contact can be probed, which can facilitate the carrier collection at the back surface and can be adapted to semitransparent, bifacial, or tandem solar cells. However, typical electron selective layers (ETL), such as CdS, have low compatibility with CZTS in a superstrate architecture . Here, a compact or nanostructured thin film of TiO 2 can be adopted as ETL .…”