Fabrication of CdS micropatterns: Effects of intermolecular hydrogen bonding and decreasing capping ligand

Novel branch-like CdS micropatterns were synthesized using thiosemicarbazide (NH2NHCSNH2) both as a sulfur source and as a capping ligand in a methanol/water system. The thiosemicarbazide/CdCI2 ratios were found to effectively play crucial roles in the morphologies of CdS crystals. With the ratios decreasing from eight to one, the CdS crystals exhibited different morphologies, from spheres to spindle-like morphologies mediated by cauliflower- and branch-like micropatterns. Control experiments using different sulfur sources showed that the NH2 groups, which could form hydrogen bonds, were necessary for the formation of the novel branch-like patterns. On the basis of the experimental results, a formation mechanism was proposed, which was supported by time-resolved experiments and IR analysis.