Research groups around the world are investigating tin (II) monosulfide (SnS) via various deposition methods and heterostructures for thin film solar cells. The maximum achieved efficiency has yet to reach 5% despite the promising properties of SnS. SnS devices have achieved high short-circuit current densities near 20 A/cm2, but open-circuit voltage and fill factor are significantly lower than models predict. The multi-valency of tin, complex Sn-S phase diagram, and layered nature of SnS result in a complex system and large variability in the microstructure of the material. Microstructure growth is largely dependent on the deposition method, thus impacting optoelectronic properties. As a result, thin film SnS made by different processing methods cannot be compared without first considering the differences in microstructure. This review evaluates SnS, including theoretical and experimental work, and its progress as a photovoltaic absorber. Single crystal and thin film growth methods as well as the properties of the material are reviewed. Solar cell structure, back contact metals and doping are evaluated to summarize the progress in implementing SnS into devices. The challenge of sulfur volatility is a serious issue for producing high-quality SnS, and is not weighted enough in the literature. In addition, the impact of device processing following SnS deposition is not considered in any studies. The best future approach for SnS-based devices will consider sulfur content a priority, and investigate the impacts of device processing on the SnS layer.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films