Versatile Surface-Active Ionic Liquid: Construction of Microemulsions and their Applications in Light Harvesting
The article outlines towards the sustainable way to the synthesis of advanced materials such as core/shell Quantum Dots (QDs) and their in-situ stabilization using microemulsions (MEs). QDs are the versatile materials which show unusual optical properties. We have constructed MEs consisting of an Ionic Liquid (IL) based surfactant i.e. choline dioctylsulfosuccinate, [Cho][AOT] as an emulsifier, toluene as nonpolar phase and water as polar phase. The system forms a large single-phase region in phase diagram without any co-surfactant. Spontaneous formation of micelles has been observed and studied through tensiometer, fluorescence and isothermal titration calorimetry (ITC). Exceptional swelling behaviour of MEs was studied using Dynamic Light Scattering (DLS) and small angle neutron scattering (SANS). In MEs droplets i.e. Reverse Micelles (RMs), we successfully synthesized spherical core/shell QDs (size ~3 to ~6 nm) with a precise control over size and morphology. The QDs have been characterized using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Powder X-ray Diffraction (PXRD). QDs stabilized in MEs exhibited excellent optical properties and can be suitably used as light harvesting material for diverse applications.