The pH of reaction solutions played a vital role and determines the nature of the final product formed. According to our experimental findings, we were able to control energy band gap, size and configuration of cobalt selenide thin films from aqueous solutions by suitable control of last solution pH. We present a simple solution processed synthesis route for cobalt selenide nanostructure thin films using chemical bath deposition method. The films were characterized by X-ray diffraction, UV–visible spectroscopy for energy band gap estimation and scanning electron microscopy to surface morphology investigation. In this work, the size of the nanosphers and other nanoparticles are relatively easy to control by pH controlling.
