Investigation of Kelvin Probe Force Microscopy and optical properties of F8BT polymer incorporated with ZnONR/AgNP nanocomposite

The optical properties and work function of poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) and its nanocomposites with ZnO nanorods (ZnONRs) and silver nanoparticles (AgNPs) were extensively studied using techniques such as Scanning Probe Microscopy (SPM) and optical spectroscopy. Kelvin Probe Force Microscopy (KPFM) measurements revealed significant differences in contact potential and a work function of around 4.484 eV for pure F8BT. Furthermore, optical absorption measurements showed increased absorbance and noticeable changes in bandgap when AgNPs and ZnONRs were added, indicating improved light-absorbing properties of the nanocomposites. The band gap of F8BT is typically around 2.50 eV, but the introduction of ZnO nanorods increases it to 2.63 eV. This could be due to the interaction between F8BT and ZnONRs. Additionally, the incorporation of silver nanoparticles (AgNPs) further raises the band gap to 2.66 eV. Analysis of the Photoluminescence (PL) spectra reveals a significant increase in emission intensity for the F8BT/AgNP/ZnONR combination, attributed to exciton recombination and the impact of localized surface Plasmon resonance in the nanocomposites.