Abstract

The present study investigated the fungal derived synthesis and characterization of core/shell silver nano- particles (F-AgNPs), and their application in a CdS thin film semiconductor. Agaricus bisporus extract content determined F-AgNPs yields. TEM analysis revealed spherical (17 nm), non- aggregated silver core/shell-structured nanoparticles. TGA analysis of F-AgNPs shows a lower decomposition temperature (97 degrees C) than its respective fungal extract control (F-C) (127 degrees C), probably due to silver's heat- conducting properties. Besides, a novel, fast and low-cost mechanical technique for covering CdS thin film semiconductors with these F-AgNPs was developed, rendering a methodological innovation. These nanoparticles presented remarkable auto-adherent properties towards CdS thin films. The effects of the fungal-derived core/shell nanoparticles coating on the thin films were assessed, finding that this coating improves their electrical conductivity, keeping their optical transmittance. Additionally, evidence is presented that shows that even the sole fungal extract control (F-C) treatment produces a surface modification of the films, decreasing both the electrical resistivity and optical transmittance probably due to the extract's fungal melanin. SEM images show that those films with FAgNPs coatings present the smoothest surface analysed (compared to F-C coated and non-coated CdS thin films). Ag presence on the surface of the F-AgNPs coated CdS thin films was confirmed by TXRF. It is proposed that these fungal-derived core-shell nanoparticles could have applications in CdS-based optoelectronic devices, decreasing the film's electrical resistance, while keeping its good optical properties and that the simple mechanical coating method developed can be useful under that perspective.