Optical and morphological features of poly(vinyl carbazole)/ferrite composites for potential opto-electronic applications

In this work, three composite films built upon poly(vinyl carbazole) (PVK) and Fe3O4, FeLiO2 and (La0.6Sr0.4) (Co0.2Fe0.8)O3 (LSCF) ferrites were produced by sonication and drop-casting. The optical absorption, emission, and band gap properties of all samples were investigated using optical spectroscopy techniques and morphological analysis by scanning electron microscopy (SEM). After introducing the ferrites, the optical absorbance of PVK in the range between 280 and 400 nm increased, whereas its bandgap systematically reduced. On the other hand, emission spectra of PVK were broadened with all ferrites and blue-shifted only in the presence of FeLiO2. Meanwhile, PVK excited state lifetimes were significantly shortened, thereby suggesting the creation of donor/acceptor states in the bandgap, which ultimately suppress the PVK emission. Although SEM images showed the presence of aggregated ferrites, most of them were readily dispersed in the PVK matrix.