Protein (bovine serum albumin) driven copper selenide and copper telluride nanostructures: structural, optical and electrical properties

Copper selenide and copper telluride nanostructures were synthesized using Bovine serum albumin, for the first time, via a facile hydrothermal method. The involvement of different precursors was proposed through a probable reaction mechanism. Moreover, the structural and optical properties of the prepared Cu(2−x)Se and Cu(2−x)Te nanostructures were investigated. The average sizes of the synthesized copper selenide nanoparticles were in the range of 87 ± 24 nm. Variation in size and shape for copper telluride nanostructures gave round shape nanoparticles as well as rods in micro and nano size and average size for small and large round shape nanoparticles were 52 ± 16 nm and 216 ± 27 nm, respectively. More precisely, size-strain plot and the Williamson-Hall analysis methods were adopted to determine the lattice strain and crystalline sizes of the synthesized nanoparticles. The optical band gap energy of prepared nanoparticles estimated from the UV–Vis spectroscopy was 2.95 and 2.32 eV for Cu(2−x)Se and Cu(2−x)Te nanoparticles, indicating quantum confinement effect due to the deviation from bulk materials to the nanoscale. Moreover, the band gap decreased with enhancement of BSA concentration which suggest that the usage of BSA content is important factor and must be optimized for obtaining desired optical band gap. The electrical conductivity for copper selenide and copper telluride was found as 0.048 − 0.064 × 105 S cm−1 and 0.011 − 0.017 × 106 S cm−1 respectively.