Influence of Tb incorporation on the structural and the optical properties of ZnO nanoparticles

► Tb incorporates mostly on the surface in Tb doped ZnO nanoparticles. ► Band gap energy increases by introducing a hydrostatic compressive strain in the nanoparticles. ► Significant variation of the band gap with particle size for ZnO nanoparticles is observed. ► A new way to tune the optical properties of ZnO nanoparticles for the optoelectronic applications. ► An opportunity to study the pressure dependence of the optical properties of ZnO nanoparticles.