In this work, ZnSe:Cu(0,0.1,0.75,1.5, 2.25, 3%) nanoparticles (NPs) were synthesized by microwave-assisted hydrothermal method. The exact value of the energy gap (Eg DASF) of nanoparticles was determined by the absorption spectrum fitting derivative method (DASF). For the synthesized NPs, optical properties such as, linear (n) and nonlinear refractive indices (n2), linear and third-order nonlinear optical susceptibilities (χ(1), χ(3)), reflection loss (RL) and transmission coefficient (T) were determined. Also, the electronegativity (χ*) of the samples was determined. Results revealed that these nanoparticles have a high potential for optical and optoelectronic applications; specially, samples containing 1.5 & 2.25% of Cu-impurity, owing the lowest optical band gap and the highest optical susceptibilities, are introduced as the best candidates.
