SnS nanocrystalline thin films for n-CdS/p-SnS solar cell devices

Tin sulfide (SnS) thin films were galvanostatically electrodeposited on glass/Indium-Tin Oxide (ITO)/Cadmium Sulfide (CdS) substrates from a non-aqueous solution. The effect of different DL-tartaric acid concentrations and various annealing environments (vacuum, air and argon) on the electrical and physical properties, secondary phase formation and performance of the solar cells were investigated in this study. From X-ray diffraction (XRD) and Raman spectra, nanocrystalline SnS thin films with orthorhombic structure were produced with some secondary phases of SnS₂ and Sn₂S₃ which decreased by annealing in air and Ar atmospheres. Cyclic voltammetry studies showed that the films have good electrochemical properties and photoluminescence analysis indicates that the samples have a direct band gab energy about 1.55 eV. Chemical composition and morphological structure of the nanoparticles were identified using energy dispersive X-ray analysis and scanning electron microscopy, respectively. The current-voltage (I-V) characteristics (under dark) and capacitance-voltage (C-V) relations for the fabricated devices (glass/ITO/n-CdS/p-SnS/Mo), for the SnS thin film annealed under Ar environment, exhibited a rectifying behavior with a saturation current and carrier concentration of ~ 10^-6 A and 10¹⁶ cm^-3, respectively. The illuminated cell have an efficiency of 4.35%, which was investigated with an illumination intensity of 100 mW/cm² and the output parameters; short circuit current density (Jsc), open circuit voltage (Voc) and fill factor (FF) are 13.6 mA/cm², 1000 mV and 0.32, respectively.