Structural, optical and dielectric properties of green synthesized Ag2S nanoparticles

Abstract

A facile, convenient, environment friendly green synthesis method has been used to synthesize Ag₂S nanoparticles (NPs) using lemon extract. The various characterizations such as XRD, FESEM, FTIR and UV–Vis absorption spectrum confirm the good quality of nanosized Ag₂S particles. The temperature and frequency dependent dielectric properties have been studied to investigate the electric behaviour of Ag₂S NPs. A relaxation peak observed in loss tangent vs. frequency plot and it shifted towards higher frequency with increasing temperature. The variation of AC conductivity with frequency reveals that at lower frequency region obeys Jonsher’s Power Law (JPL) and Super-linear Power Law (SPL) at higher frequency region. Non-overlapping Small Polaron Tunnelling (NSPT) model is used to clarify the conduction process of JPL portion of the curve. The Nyquist plot of the sample has demonstrated two semi-circular arches, which suggests the effect of grain and grain boundary resistance in the Ag₂S NPs. The grain and grain boundary resistance decrease with increasing temperature, which indicates the Negative Temperature Coefficient of Resistance (NTCR) behaviour like a semiconductor. The activation energy (E_a) has been estimated from the temperature dependent AC conductivity measurement. The P-E hysteresis loop measurement of Ag₂S NPs shows the relaxor-ferroelectric behaviour at room temperature. The fabrication of p–n junction diode (Ag₂S/Si) has been constructed and demonstrated the diode characteristics for the device applications.