Cd xZn 1− xS–arachidic acid composite LB films

Abstract

Mixed LB multilayers of cadmium arachidate–zinc arachidate (CdA–ZnA) have been exposed to H 2S to form Cd x Zn 1− x S alloy nanoclusters within the multilayers. FTIR and UV–vis spectra of H 2S exposed multilayers showed that the conversion of arachidate salt into arachidic acid (AA) and sulphide formation begins in the first 5 min and is completed in ∼3 h of H 2S exposure. X-ray reflection studies and the nature of CH 2 scissoring band of the composite multilayers show that the formation of sulphide nanoclusters is accompanied by the formation of molecular chain domains with different polymorphic phases of AA, depending upon the relative proportions of CdA and ZnA in the precursor multilayer. Depending upon the CdS and ZnS content, the absorption edge is found to continuously shift from that of pure CdS to that of pure ZnS nanoclusters, indicating the formation of Cd x Zn 1− x S alloy nanoclusters in the arachidic acid matrix. The nanocluster formation is more facile in the mixed archidate multilayers than in pure CdA or ZnA multilayers.