Highly Luminescent and Temperature Stable Quantum Dot Thin Films Based on a ZnS Composite

Abstract

A solution processable Zn(EtXn)2(octylamine) precursor has been used to deposit nanocrystalline ZnS thin films which can effectively host CdSe–CdS–ZnS quantum dots (QDs) with their native surface chemistry intact. The formation of such hybrid QD:ZnS composites proceeds through the initial decomposition of the octylamine stabilized zinc xanthate precursor to form nanocrystalline ZnS. To gain insight into this decomposition process we have utilized headspace gas chromatography–mass spectrometry (HS GC-MS), thermogravimetric analysis coupled with mass spectrometry (TGA-MS), grazing angle attenuated total reflectance Fourier transform infrared spectroscopy (GAATR FTIR), and grazing angle X-ray diffraction (GAXRD). Through these characterizations we identify that the major decomposition route of Zn(EtXn)2(octylamine) to form ZnS begins at 100 °C, generating predominantly CO2, COS, CS2, and ethanol as gaseous products. The octylamine used to solubilize the metal complex is found to remain adsorbed within the Zn...