Organic/inorganic photoconductive hybrid films based on polypyrrole-cadmium sulfide quantum dot nano-composites

Nanostructure hybridization of conducting polymer with inorganic nano particles offers considerable advantages in polymer processing, device performance and/or tunability over standalone polymeric based devices [1]. In this work, the photoconductivity properties of the conducting polypyrrole–cadmium sulfide (PPy-CdS) quantum dot nano-composite films were studied. The soluble conducting PPy and the CdS quantum dot were separately synthesized [2, 3]. The SEM images indicated that the PPy nano particles and CdS quantum dot were synthesized successfully. After the preparation of PPy-CdS nano-composites with the different weight percent, electrospray coating method was then applied in order to deposit the mentioned nano-composite on the surface of interdigital electrodes (IDEs). This film was then connected as one resistance of a Wheatstone bridge and its photoconductivity properties were investigated while illuminating the film in the IR region (4000-400 wavenumber). Observations showed that when the film absorbed IR radiation, a current was passed through the Wheatstone bridge circuit and this photocurrent was proportional to the hybridization percentage. The current values produced by the nano-composites which are in the range between 89-117.8 μA are higher than that of the pure PPy film (70 μA ).The maximum current was related to the film with 20 weight percent of hybridization. The produced photocurrent was well repeated. As a result, the prepared organic-inorganic hybrid films provide excellent photoresponsive materials which can be applied in photo detection devices.