Synthesis of DI- and trialkylthiourea complexes of Cd, Mn and Ni as precursors for phosphonoacetic acid (PAA)-capped metal sulphide nanoparticles

摘要

Many studies on thiourea and its derivatives in different metal (II) complexes have confirmedudthat coordination is through the sulphur atom. The bonding of substituted thioureas touddifferent metals was confirmed with a combination of spectroscopic studies such as IR andudNMR spectroscopy and elemental analysis. A series of metal (II) di- and trialkylthioureasudcomplexes have been synthesized and characterized. Their bonding through sulphur atomsudrendered these complexes good precursors for the preparation of metal sulphideudnanoparticles. Thermogravimetric analysis on the complexes was undertaken to check theirudsuitability as precursors for the synthesis of nanoparticles and their potential as precursors forudmetal sulphide thin films using the chemical vapour deposition (CVD) technique and theirudgeneral chemical and thermal stability.udAll the complexes reported in this work were used as single source molecular precursors forudthe synthesis of cadmium, manganese and nickel sulphide nanoparticles. In this study theudinvestigation on the influence of capping agent and temperature on the size and morphologyudof nanoparticles was undertaken. Nanoparticles obtained by thermolysis of precursors inudphosphonoacetic acid (PAA) were bigger in size and rod-shaped compared to smaller rodsudobtained in hexadecylamine (HDA). CdS nanoparticles prepared using PAA as a cappingudagent showed a huge blue-shift of the band edge from the bulk of 515 nm, compared to CdSudnanoparticles obtained using HDA as a capping agent. When PAA was mixed withudtrioctylphosphine oxide (TOPO), a blue shift of band edges in all the bulk materials ofuddifferent metal sulphides prepared was observed and the rod-shaped nanoparticles changed toudspherical particles.