Structural influence of nitrogen adducts on the morphology of bismuth sulfide thin films

Four adducts of bismuth ethyl xanthate Bi(S 2 COEt) 3 .L [L = tetramethylethylenediamine (TMEDA), triethylamine, 1, 10 phenanthroline or pyridine] have been synthesized and characterized. Analyses of the crystal structures revealed that the prepared Bi(S 2 COEt) 3 and its 1, 10 phenanthroline adduct crystallise in the triclinic space group P-1 as reported earlier for the former. The Bi(S 2 COEt) 3 had a triangular prism geometry whereas its 1, 10 phenanthroline adduct had a pentagonal–bipyramidal geometry. Spin coating of the complexes on glass substrates followed by heating at 200 °C under nitrogen atmosphere for 30 min decomposed all the complexes to form Bi 2 S 3 thin films as confirmed by p-XRD. SEM showed that the adduct had an effect on the morphology of the Bi 2 S 3 thin films formed changing from wires for TMEDA to cluster of rods for triethylamine and pyridine to dots for 1, 10 phenanthroline. EDX analyses, however, showed approximately a 2:3 Bi to S ratio. Graphical abstract