PROPERTIES OF SINGLE POT SYNTHESIZED COMPOSITION TUNABLE PbSe-CdSe CORE-SHELL and CdXPb1-XSe NANOCRYSTALLITES

Abstract

This work describes an experimental investigation of method of synthesis, and determination of structural and physical properties, and analysis and correlation of the properties to the structures of PbSe-core, PbSe-CdSe core-shell, ternary CdXPb1-XSe nanocrystallites and nanocrystallites - polymer hybrid structures. These structures are investigated for applications in flexible solar cell devices. The main synthesis process used in the work was a Single Pot Synthesis of PbSe-core quantum dots as well as core- shell structure which is the novel approach for the core shell formation in our case. As, in literature survey, it was found that same material PbSe-CdSe was synthesized using double pot synthesis, SILAR (successive ion layer adsorption and reaction)process and Partial Cation Exchange method in most of the research papers). Analytical instruments that include Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM), Scanning Tunneling Microscopy (SEM), X –Ray Diffraction (XRD) were used for structural characterization and Fourier Transform Infrared Spectroscopy while optical absorption spectroscopy was used for determining the quantum confinement of charge carriers in PbSe-core as well as in core-shell and ternary nanostructures. In addition, fluorescence quenching of nanocomposite of P3HT with various structure with varied amount of CdO precursor (from 0 to 20%) as per molarity ratio of CdSe/PbSe was also studied. With this single pot approach, absorption spectroscopy shows red shift in the spectra as Cd content increases .Fluorescence quenching also shows higher charge transfer in core-shell structure as well as in ternary PbxCd1-xSe quantum dots as compare to PbSe-core nanostructures. From results one can infer that PbSe-CdSe core-shell nanocrystallites and its respective composites with polymer can be used for OPV (Organic Phovoltaic Devices) owing to its higher charge transfer efficiencies.