Phase optimization study of orthorhombic structured SnS nanorods from CTAB assisted polyol synthesis for higher efficiency thin film solar cells

Orthorhombic SnS nanorods were prepared from CTAB assisted polyol synthesis method at reaction temperature of 150 °C. In this method, the source (Sn, S) concentration ratio, CTAB concentration and reaction time were optimized to obtain single phase SnS as evident from Raman and XPS analyses. Crystal structure from XRD along with SAED pattern confirmed the formation of orthorhombic SnS structure. Morphological analysis from HR-TEM revealed the formation of SnS nanorods with improved homogeneity in size and shape by increasing the reaction time and CTAB concentration. The observed shift in the absorption band edge and absorption maxima by varying the CTAB concentration and reaction time is very well correlated with the morphological and chemical structural variations. Tauc plot shows the successful tuning of band gap value to 1.5 eV which is the optimum value of thin film solar cells, by varying the reaction time of sample with 0.025 M of CTAB. Electrical properties were studied from the Hall measurement which showed p-type conductivity for single phase SnS while n-type conductivity observed for mixed phases.