Symmetry-Breaking Segmented Selenium Nanorods and Nanowires: Synthesis via Coupling of Nanorods

We present a facile route to prepare selenium nanorods (SeNRs) with alternating symmetry-breaking segments dispersed in aqueous solution. The key roles in this preparation include an assistance provided by the carboxymethyl–cellulose (CMC) and a careful control in particle’s nucleation and growth. Thus, prepared symmetry-breaking segmented SeNRs, namely, SBS-SeNRs, show discrete trigonal and quasi-trigonal phases in the form of repeating quasi-trigonal–trigonal–quasi-trigonal, (tq–t–tq)n, where tq stands for the quasi-trigonal phase in the space group of P321 and t is the trigonal phase in the space group of P3121. Evidence from the particle dimensions analysis during the growth and the result of post-synthesis surface modification showed that the SBS-SeNRs grow via two different particle couplings. The first one was found in the early stage that very short monoclinic Se nanorods couple together with a simultaneous phase transition to trigonal SeNR. The second coupling occurs at the later stage by the cou...