Novel double layer film composed of reduced graphene oxide and Rose Bengal dye: design, fabrication and evaluation as an efficient chemosensor for silver(i) detection

In the present study, a novel double layer film (DLF) composed of Rose Bengal dye and reduced graphene oxide (RB/rGO-DLF) was fabricated via a facile combined (ultrasonic-spin coating) method as a silver(i) ion sensor in an aqueous environment. Microscopic and spectroscopic characterizations confirmed the successful synthesis of RB/rGO-DLF. The morphological results of FE-SEM and AFM studies confirmed the monotonous and uneven surface of the RB/rGO-DLF. Moreover, XPS analysis also proved the reaction between silver ions and Rose Bengal immobilized on the rGO structure using binging energy (B.E.). Leaching of the chemosensor was studied and the results suggest that the prepared chemosensor is constant during the sensing process without any considerable variation in its critical characteristic properties such as sensitivity, selectivity and response time. The UV-vis spectra showed the presence of two different peak intensities at 520 and 557 nm. The first peak can be attributed to the Ag-RB combination with a response time of 5 minutes at pH 7. The sensing calibration plot exhibits a linear range between 8.53 x 10(-7) and 3.39 x 10(-6) mol L-1 of silver ions with a linear equation of absorbance = 0.116 [Ag+] - 0.088 and a correlation coefficient of 0.987. The limit of detection (LOD) based on 3 sigma of the blank is 9.55 x 10(-8) M.