Abstract

This work reports photoelectric sensor application of a composite based on polyaniline (PANi), hydrolysed pectin (HPEc), graphene (GR) and cadmium sulfide (CdS) with examination of electrical, electrochemical and band gap properties. Cadmium sulfide was used for upturn of electrical and optical properties of the composite. The presence of graphene, CdS and PANi cause the synergy effect and the promotion of photoelectric sensor of the composite. Pectin was utilized as a polyelectrolyte for increase of solubility and processability of nanocomposite for better dipsertion of nanoparticles. The GR/CdS@HPEc-PANi and GR@PANi nanocomposites was synthesized via in-situ emulsion polymerization and characterized via FTIR, SEM, XRD, EDX, TEM and TGA analyses. TEM analysis showed a continuous regular network of of copolymer and cadmium sulfide dots on the crystalline layers of graphene. TGA thermal analysis displayed higher thermal stability about 40% for GR/CdS@HPEc-PANi with residual weight of 60g than of GR@PANi nanocomposite with residual weight of 20g. The electrochemical properties showed better electrochemical performance for the GR/CdS@HPEc-PANi relative to the GR@PANi nanocomposite. The band gap calculation obtained a band gap of about 2.7 for the nanocomposite. The photoelectric test showed the photoelectric sensitivity of the GR/CdS@HPEc-PANi nanocomposite toward light irradiation and the electron transfer impedance of the nanocomposite was reduced under light relative to dark conditions. The CV curves of the nanocomposite showed a non-linear behavior which indicate semiconducting nature of the nanocomposite. Also, chronoamperometry test showed the stability of the nanocomposite under different cycles and current.

Keyword: Polyaniline; Pectin; Cadmium Sulfide; Graphene; Photoelectric sensor; Electrochemical properties