Low-temperature chemical synthesis and stabilization of silver nanoparticles for optical power limiting applications

Chemical synthesis of silver nanoparticles (AgNPs) was performed using a chemical reduction method and its optical limiting activity is discussed in this article. The prepared AgNPs were tested under laser light and showed a clear path of the laser light indicating the dispersion of the laser beam via the nano-range particles. The morphological and energy dispersive spectra indicated the availability of AgNPs with a particle size of 3–13 nm. The absorption spectra of the prepared AgNPs stabilized by polyvinyl pyrrolidine confirmed that the AgNPs with 0.5 ml polyvinyl pyrrolidine were the most stable. The prepared AgNPs were stable for up to 60 days. The band gap of the prepared AgNPs was confirmed as 2.4 eV. The Fourier-transform Infrared spectra confirmed the stretching vibrations of the CO and O-H bonds. Field emission scanning electron microscopy images confirms the formation of AgNPs and the elemental composition confirmed that the prepared AgNPs has a weight percentage of 24 % Ag atoms. Tunneling electron microscopy analysis confirmed that the average particle size of AgNPs was 9 nm. The diffraction pattern obtained indicates the Face-centered cubic crystal structure of the AgNPs. In the Z-scan experiment, a valley-like pattern with a minimum at the origin was observed for the normalized transmittance versus distance (Z(mm)). The optical limiting pattern decreases the transmittance with increasing input intensity. The results reproduced by Z-scan analysis shows the optical limiting characteristics of the prepared AgNPs which can be employed for the fabrication of laser safety devices.