A facile route for synthesis of CuInxGa1−xSe2 nanocrystals with tunable composition for photovoltaic application

Abstract

A facile colloidal synthesis of CuIn x Ga 1-x Se 2 (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 2 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 2 nanocrystals, obtained for samples synthesized with pure OLA and with mixed solvent.

Synthesis and Characterization of CuIn1−xGaxSe2 Semiconductor Nanocrystals

“…There are various methods for manufacturing CuIn 1− x Ga x Se 2 nanocrystals, such as hot injection synthesis [ 5 , 18 ], the solvothermal route [ 4 ], thermal decomposition [ 19 , 20 , 21 ], the modified polyol route [ 22 ], and the mechanochemical process [ 23 ]. Cui and co-workers synthesized CuIn 1− x Ga x Se 2 nanocrystals by heating metal chlorides in a selenium solution containing oleylamine and glycerol [ 24 ]. Recently, two-step procedures, which include a low temperature (110 °C) nucleation stage lasting 24 h followed by a growth step at higher temperature (240 °C) lasting 1 h, to synthesize CuIn 1− x Ga x Se 2 nanocrystals with sphalerite or wurtzite phase were reported [ 25 ].…”