Solvothermal synthesis of CulnSe_2 nanostructured powders: comparing open-air with applying internal imposed pressure

摘要

Nanocrystalline CulnSe_2 (CIS) powders were synthesized with a simple open-air solvothermal method as well as under conditions of applying internal imposed pressure. No post-treating processes such as annealing or selenization were used in both methods. The synthesis processes involved the reaction of precursors in an autoclave for different process times. Structural, morphological, and opto-electronic properties of CIS powders were compared. X-ray diffraction patterns (XRD) confirmed the formation of chalcopyritc structure of CIS powders in both approaches at reaction temperature of 220°C and for short process time. Field emission scanning electron microscopy (FESEM) results show that while CIS powders synthesized under the atmospheric condition are mostly agglomerated, particles have more specific shapes in samples synthesized under internal imposed pressure. Furthermore, the band gap energies of synthesized CIS powders were obtained using diffuse reflectance UV-vis spectroscopy (DRS) measurements.