Effect of layer thickness variation on sensitivity: An SPR based sensor for formalin detection

Abstract

Food preservatives and additives are the universal concern of recent days. Particularly, formalin is a chemical compound that is being commonly mingled with food for the preservation purpose. The recurrent ingesting of formalin contaminated food causes uncompromising health sicknesses like chronic cancer. Therefore, identification of formalin in food substances is an extreme need and day by day this need is growing as a general issue in the emerging terrains. In this article, a surface plasmon resonance (SPR) based sensor, comprised of graphene-PtSe2 combined layers associated with a ZnO nano-sheet is presented for the detection of formalin in liquid solution. The performance of the sensor has been analyzed through an analytical approach using MATLAB commercial software. Consequence due to incorporation of the Graphene-PtSe2 combined layer into the sensor structure along with ZnO layer has been studied. The observed sensitivity and quality factor are 155.33° RIU−1 and 88.89 RIU−1, respectively. This sensor senses the presence of formalin molecules by using attenuated total reflection (ATR) approach, assessing the reflectance vs SPR angle. It is found that the sensitivity of the conventional SPR based sensor is 128.33° RIU−1, whereas an improved sensitivity of 155.33° RIU−1 is obtained for this proposed amalgamated sensor structure. Later in time, a comparison of performance for different SPR sensor structures and the proposed sensor has been studied. Finally, another comparison study has been made with performance of the proposed sensor to other reported sensor in the literature.