A Facile Synthesis Routine of Ag2S–CdS Heterostructure Nanorods with Enhanced Trap Emissions

We explored a facile routine to synthesize morphology-controlled Ag2S–CdS heterostructures. The heterostructures were achieved by a two-step method where CdS nanorods were prepared in the first step, acting as the substrates inducing successive cation exchange reaction between Cd2+ and Ag+ ion. The nucleation sites of Ag2S can be readily controlled by varying the feed ratios of Ag+ to Cd2+ ion, thus leading to formation of heterostructures with different morphology where Ag2S particles grow on the tips of the CdS rods, or at multiple locations across the nanorods. HRTEM analysis showed that Ag2S particles were grown on the varied sites of CdS rods with a coherent, quasi-epitaxial interface having different degrees of lattice mismatch. Photoluminescence results showed that, compared to bare CdS nanorods, enhanced trap emissions were observed after the growth of Ag2S particles on the rods, which can be attributed to the strained interfaces instead of impurities doping.