Structural and morphological evolution of CdS nanosheets-based superstructures by surfactant assisted solvothermal method

Evolution of novel cadmium sulphide brick-like structures from the spherical hierarchical architecture under solvothermal condition is investigated. The cadmium sulphide spherical hierarchical nano-architecture transformed to brick-like structures with the addition of cetyltrimethylammonium bromide. The X-ray diffraction patterns of the cadmium sulphide nanostructures indicated a phase transition from cubic to hexagonal phase. PL results showed an enhanced band edge luminescence and the removal of defect states for cadmium sulphide brick-like structures. HRTEM results showed that the size of the cadmium sulphide nanoparticles of the brick-like structures were smaller than those of the spherical hierarchical architectures. In the synthetic process, cetyltrimethylammonium bromide plays a crucial role in controlling the morphology, and introducing a phase transition as well as effectively removing the defect states. Hence cetyltrimethylammonium bromide is an excellent structural and morphological director surfactant. A possible formation scheme of the cadmium sulphide brick-like structures is proposed. Highlights: ► Novel CdS nanobricks can be synthesized by solvothermal method using CTAB as a surfactant. ► CTAB influences crystal structure of CdS nanostructures from cubic to hexagonal. ► Blue shift in band gap and defect level emissions is suppressed by CTAB in CdS nanostructures. ► A possible growth mechanism is proposed for CdS nanobricks.