Synthesis of CdS nanorods and nanospheres: shape tuning by the controlled addition of a sulfide precursor at room temperature

Abstract

Shape tuning of CdS nanocrystals (NCs) by controlled growth and stabilization by tetraoctyl ammonium bromide ligands in non-aqueous medium is thoroughly investigated in this report. CdS nanorods and nanospheres were synthesized by manipulating the addition rate of the sulfide precursor. A higher addition rate (10 mL min(-1)) of the precursor yields nanorods and a lower addition rate (1 mL min(-1)) of the precursor yields nanospheres whereas an addition rate (7 mL min(-1)) in between these two addition rate yields a mixture of nanorods and nanospheres. The investigation further revealed that an optimum concentration of stabilising agent decides the shape, whereas the precursor mole ratio does not play any significant role in shape tuning. The band edge and trap state emission of the NCs synthesized were analysed by time resolved emission studies.