Photovoltaic Behavior of Nanocrystalline SnS/TiO₂

Abstract

Nanocrystalline tin sulfide (SnS) was prepared by chemical bath deposition, and the photovoltaic behavior of SnS/TiO 2 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 × 10 4 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/TiO 2 structure, with an open-circuit voltage (V oc ) of 471 mV, a short-circuit current density (J sc ) of 0.3 mA/cm 2 , 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/TiO 2 are discussed.

Suitability of SnS thin films for photovoltaic application due to the existence of persistent photocurrent

“…SnS has been successfully fabricated by chemical methods [3]- [6], spray pyrolysis [7]- [9], sputtering [10], thermal evaporation [2], [11]- [13] and electron beam assisted evaporation [14]. The band-gap of the films were reported to lay between 1.3-2.5 eV [1], [15]- [18] depending on the fabrication technique.…”

Enhancing the efficiency of SnS solar cells via band-offset engineering with a zinc oxysulfide buffer layer

“…11 Recently, a record efficiency SnS solar cell of 1.95% (active area) was fabricated from p-n homojunction nanowires using boron and phosphorus as dopants. 12 In addition, SnS-based solar cells have been reported using different n-type partners such as ZnO, 13 CdS, 14,15 Cd 1 − x Zn x S, 16 SnS 2 , 17 TiO 2 , 18 and a-Si. 19 So far, the best SnS planar heterojunction device was fabricated with SnS/CdS, achieving a power conversion efficiency (η) of 1.3%.…”

Band alignment of SnS/Zn(O,S) heterojunctions in SnS thin film solar cells

“…). 1 There have been numerous reports on SnS-based thin film solar cells with various buffer layers, including SnS 2 , 2 CdO, 3 Cd 2 SnO 4 , 3 CdS, [4][5][6][7][8][9][10] Cd 1Àx Zn x S, 7 ZnO, 11,12 TiO 2 , 13 PbS, 14 and a-Si. 15 The prevalent low efficiencies can be attributed to various sources, such as bulk material impurities and defects, interface trap states, and notably unfavorable heterojunction band alignment.…”