A new route for the synthesis of CuIn0.5Ga0.5Se2 powder for solar cell applications

In this paper, a new and simple method is described that does not use an autoclave to synthesize copper indium gallium diselenide (CuIn0.5Ga0.5Se2) particles from the constituent elements. The process also does not require a post-synthesis selenization step. A solvo-thermal route is followed in which the constituent element powders are dissolved and made to react in a solvent such as ethylenediamine (ED), or triethylenetetramine (TETA). Crystal structure, morphology, composition, and particle size distribution of prepared particles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and dynamic light scattering (DLS), respectively. The band gap energies of the prepared particles were determined using an UV–VIS–NIR spectrophotometer. The results indicate that the solvent temperature and the synthesis time significantly affect the formation of single-phase CuIn0.5Ga0.5Se2 and the crystallinity of the particles. Further, the measured band gap energy for the prepared particles is close to that of the bulk material. For example, the single-phase plate-like CuIn0.5Ga0.5Se2 particles with an average particle size of 413.9 nm which can be successfully synthesized at a temperature of 250 °C in 15 h, have a band gap energy of 1.15 eV.