Opto-structural Insights Into Zno-doped Ps Nanocomposites: Photoluminescence Spectroscopy and Defect Analysis

Abstract In this study, zinc oxide nanoparticles (ZnO NPs) were successfully incorporated into polystyrene (PS) using a combination of solution casting and hot-pressing, yielding a range of PS/ZnO nanocomposites. These nanocomposite films were characterized using ultraviolet visible spectroscopy (UV-Visible), photoluminescence (PL), and X-ray diffraction (XRD) techniques. Hexagonal wurtzite structure of ZnO nanoparticles was confirmed by X-ray diffraction (XRD) results. XRD analysis demonstrated a transition in crystallinity from 3.88 nm to 1.58 nm, further confirming the impact of ZnO concentration on structural properties. The optical absorption spectra were used to determine optical energy band gaps, where their values indicated an improvement in the optical characteristics of the nanocomposite films. PL spectra interpretation elucidated optically active defects and relaxation pathways, with wide emission bands in the violet and blue regions suggesting transitions from excitonic levels and/or zinc interstitials (Zni) to the conduction band, alongside contributions from defects like zinc interstitials (Zni) and natural zinc vacancies (Znv). These findings deepen our understanding of the intricate relationship between ZnO nanoparticle concentration and the optical and structural characteristics of PS/ZnO nanocomposite films, offering insights essential for diverse applications.