Shape-controlled synthesis of three-dimensional branched CdS nanostructure arrays: structural characteristics and formation mechanism

Abstract

Through a combination of electrodeposition and subsequent solvothermal reaction, three-dimensional (3D) branched CdS nanostructure arrays were fabricated by nanowires self-assembly in ethanediamine solution containing thiourea and hexamethylenetetramine (HMTA) for the first time, where HMTA acted as a capping agent. In the absence of HMTA, only disordered CdS nanowires were obtained. The reaction conditions influencing the synthesis of 3D branched CdS nanostructure arrays, such as the concentration of HMTA and thiourea, reaction temperature and reaction time, were studied and optimized. The 3D branched CdS nanostructure arrays were characterized by X-ray diffraction, field emitting scanning electron microscopy and transmission electron microscopy. The results show that HMTA played an important role in the formation of 3D branched CdS nanostructure arrays. A growth process of HMTA-assisted gradual crystallization and subsequent oriented attachment was proposed as a plausible mechanistic interpretation for the formation of the 3D branched nanostructure arrays. In addition, the photoluminescence property of the novel 3D branched CdS nanostructure arrays was investigated.