Tin Sulfide Films From Solution

Owing to its low cost and potentially useful electronic properties, tin sulfide is a promising candidate for applications such as photovoltaic devices. Yet the semiconductor remains largely sidelined because methods used for making high-quality tin sulfide films, such as atomic layer deposition and thermal and electron beam evaporation, are laborious and costly. A team led by Richard L. Brutchey of the University of Southern California and Nathan S. Lewis of Caltech has now demonstrated that high-quality tin sulfide films can be prepared via a simple low-temperature solution-phase method (Chem. Mater. 2014, DOI: 10.1021/cm503124u). The researchers dissolved tin sulfide powder in a mixture of ethylenediamine and 1,2-ethanedithiol at 50 °C then spin-coated the solution onto glass plates or other supports. They briefly heated the films then conducted spectroscopic, photovoltaic, and X-ray analyses. Although tin and sulfur can form SnS₂, Sn₃S₄, Sn₄S₅, and other phases, the team reports that the simple solution method yields defect-free, phase-pure SnS films that generate stable photocurrent values comparable with samples prepared by more complex deposition methods.