Investigation of optical and structural properties of ZnSe nanocrystals for heterojunction solar cell applications

Hot injection method is well established and widely used technique for the synthesis of quantum dots and nanocrystals. In the present study, we report on size, shape, and phase controlled ZnSe nanocrystals, which were synthesized by facile hot injection method. For the synthesis, zinc sulfate heptahydrate is used as Zn precursor, Selenium powder is used as Se source and Oleylamine was as the capping ligand, stabilizer. The synthesized ZnSe nanocrystals were characterized by x-ray diffraction, Raman spectra, UV-Visible spectroscopy, and Photoluminescence spectroscopy. The x-ray diffraction confirms cubic zinc-blende crystal structure with orientation along (111) plane phase with 20 nm average crystalline size for ZnSe nanocrystals. The optical properties of ZnSe nanocrystals studied using UV-Visible and photoluminescence spectroscopy and obtained excitation wavelength 545 nm with estimated bandgap is 2.24 eV. The chemically prepared ZnSe nanocrystals are good candidate as buffer layer by replacing CdS in solar cell application.