Photovoltaic behavior of nanocrystalline SnS/TiO2

Abstract

Nanocrystalline tin sulfide (SnS) was prepared by chemical bath deposition, and the photovoltaic behavior of SnS/TiO2 was studied. The X-ray diffraction pattern and transmission electron microscopy revealed an ∼6 nm SnS polycrystalline orthorhombic structure. The SnS film exhibited a band gap of 1.3 eV, and its absorption coefficient was more than 1 × 104 cm -1 in the visible light range. The electrical conductivity activation energy of the SnS film was 0.22 eV, determined when the sample was heated in the temperature range of 111-144°C. Although the sample was insulating at room temperature, photovoltaic behavior was found in a SnS/TiO2 structure, with an open-circuit voltage (Voc) of 471 mV, a short-circuit current density (Jsc) of 0.3 mA/cm2, and the conversion efficiency (η) of 0.1% under 1 sun illumination. The properties of SnS and the reasons behind the photovoltaic phenomenon of SnS/TiO2 are discussed. © 2010 American Chemical Society.