Self-assembly and photoluminescence of CdS-mercaptoacetic clusters with internal structures

CdS-mercaptoacetic (CdS/M) clusters were synthesized by using mercaptoacetic acid as the stabilizing agent in the aqueous solution. From the transmission electron microscopy (TEM) image and the electron diffraction (ED) pattern, a two-dimensional nearly ordered CdS/M cluster array is observed and the CdS/M cluster is found to be constructed of small CdS/M nanocrystals. The model of self-assembly of the CdS/M clusters with internal structure is presented. The absorption spectrum of the CdS/M nanocrystal solution reveals a maximum at 372 nm and the corresponding photoluminescence (PL) spectrum shows a strong peak at 556 nm at room temperature. The PL spectra of various concentrations of CdS/M reveal the passivation effect of mercaptoacetic acid. (C) 2000 Academic Press.