The photovoltaic properties of novel narrow band gap Cu2SnS3 films prepared by a spray pyrolysis method

Abstract

The ternary compound Cu₂SnS₃ (CTS) was fabricated by a spray pyrolysis method. The influence of the Cu precursor concentration and substrate temperature on the properties of the prepared films was investigated in detail. X-ray diffraction spectroscopy & Raman spectroscopy, energy dispersive spectroscopy, UV-vis spectrophotometry, Four-probe Resistivity Testing and Stylus Profilometry were employed for the analysis of the structural, compositional, optical, electrical and morphological properties of the prepared CTS thin films. The characterization results showed that the CTS thin film fabricated under optimal conditions (substrate temperature 350 °C, Cu concentration 0.02 M) had an atomic ratio of Cu_1.43SnS_2.59, and presented as a tetragonal structure with preferential (1, 1, 2) orientation. Optical measurements showed that the thin film had a high absorption coefficient (>10⁴ cm⁻¹) with a band gap value of 1.16 eV. The resistivity of the sprayed CTS thin film was 11.6 × 10⁻² Ω cm. All these properties indicated that the as-fabricated CTS thin film could be a promising absorber layer material for high efficiency thin film solar cells.