A facile route for synthesis of CuInGaSe nanocrystals with tunable composition for photovoltaic application.

A facile colloidal synthesis of CuInGaSe (CIGS) nanocrystals was successfully performed using a simple heating method. These nanocrystals were prepared by employing glycerol as a main solvent and oleylamine (OLA) as a complexing agent. X-ray diffraction showed that CuInSe with a chalcopyrite structure was formed by using a volume content of OLA as small as ~30 %. No variation was found in the compound phase between samples synthesized in a mixed solvent with 30 % OLA and in 100 % OLA-added solvent. Transmission election microscopy confirmed the crystal structure and showed a particle sizes below 20 nm. Energy-dispersive X-ray analysis (EDS) confirmed the chemical composition of these samples. And UV-Vis spectroscopy investigated the band gap of CIGS nanoinks. Furthermore, we used this method to prepare CIGS nanocrystals with different band gap energies by varying the In/Ga ratio of the reactants. Therefore, this green and economic route proposed has the potential for large-scale synthesis of CIGS nanocrystals, which is beneficial to low-cost photovoltaic application. Graphical abstract: XRD patterns and TEM images of CuInSe nanocrystals, obtained for samples synthesized with pure OLA and with mixed solvent.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]