Dioxin sensing properties of graphene and hexagonal boron nitride based van der Waals solids: a first-principles study† M. Kamaraj, J. Vijaya Sundar and V. Subramanian * The changes in the electronic properties of single and bilayers of graphene (G) and hexagonal boron nitride (h-BN) two dimensional (2D) sheets have been investigated upon interaction with 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) by employing density functional theory (DFT) based calculations. The calculated interaction energy, band gap and charge transfer reveal that bilayer h-BN (BLBN) may serve as a better potential candidate for sensing TCDD than the other systems. To gain further insight into the sensing properties of these materials, the transmission spectra and current–voltage (I–V) characteristics have been calculated by using Non-Equilibrium Green's Function (NEGF) combined with DFT approach. It is interesting to mention that a Negative Differential Resistance (NDR) effect has been observed in a single layer BN (SLBN) nanoribbon upon interaction with TCDD. The calculated I–V characteristics of the BLBN nanoribbon–TCDD complex reveal that the interaction between the two systems enhances the current flow through the BLBN nanoribbon, which is appreciably higher than that of pristine BLBN. These findings may open up new avenues for the application of bilayers as possible sensors for pollutants. 1. Introduction Graphene (G) is a perfect two-dimensional (2D) carbon system with zero band gap. It is one of the most fascinating materials of current century. Numerous studies have been carried out on this system due to its unique properties such as high carrier mobility, 1 quantum Hall effect, 2 high thermal conductivity and excellent optical transparency 3 etc. Hexagonal boron nitride (h- BN) is an isostructural form of G, which is called ‘white gra- phene’. It is a wide band gap semiconductor. The stacking of these 2D materials has attracted the attention of researchers due to their tunable electronic and optoelectronic properties. The advances in the synthesis of atomically thin layers of van der Waals (vdW) bonded solids have opened new possibilities for the investigation of 2D systems. Several experimental studies have been made to synthesize G and h-BN using various techniques. 4–6 The large-scale production of G 4 and h-BN 5,6 can be achieved by the chemical vapour deposition (CVD) method. The stacked homo and hetero bilayers of G and h-BN have also been synthesised using the same method. 7–10 The CVD method facilitates the successful fabrication of graphene–hexagonal boron nitride (GBN) stacked layers. 11–13 These fascinating stacked homo and hetero bilayers of 2D materials are referred as vdW solids. These have several applications in a variety of elds. 14–16 It is well known from the previous investigations that G can be used (i) as a chemical and bio-molecular sensor, 17–20 (ii) for DNA sequencing, 21 and (iii) as an energy storage materials 22 etc. The potential applications of graphene and N-doped gra- phene in catalysis have also been probed. 23,24 Graphene oxide also used as sensor to detect bisphenol A. 25 Similarly, the sensing property of h-BN has been investigated by using both experimental and theoretical techniques. 26–33 The activated boron nitride has also been used to adsorb the organic pollut- ants. 34 Lei et al. reported the importance of h-BN in the puri- cation of water. 35 Electronic properties of hBN have been tuned by various functionalization. 36,37 The applications of hetero bilayers of G and h-BN as a possible pressure sensor 38 and gas sensor 39 have also been reported. Dioxin families are the most toxic organic pollutants. They are stable pollutants in water, soil, and air. 40 It is lipophilic in nature. 41 Dioxins are released during many industrial processes as an unwanted by-product. In some natural process such as volcanic eruptions and forest re, dioxins are released. 42 Any source of organic materials in the presence of chlorine or other halogens can generate dioxins and furans during combustion. 41 The half-life of dioxin in soil and sediments is estimated to be 50–100 years. 43 Among the members of dioxin family, 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) is highly toxic due to its half-life (10 years) in the human body. 44,45 TCDD is a well-known carcinogen. The exposure of TCDD leads to skin problem called Chemical Laboratory, CSIR – Central Leather Research Institute, Adyar, Chennai 600020, India. E-mail: subuchem@hotmail.com; subbu@clri.res.in; Fax: +91 44 24911589; Tel: +91 44 24411630 † Electronic supplementary information (ESI) available. See DOI: 10.1039/c6ra18976h Cite this: RSC Adv. , 2016, 6, 107114 Received 26th July 2016 Accepted 29th October 2016 DOI: 10.1039/c6ra18976h www.rsc.org/advances 107114 | RSC Adv., 2016, 6, 107114–107126 This journal is © The Royal Society of Chemistry 2016 RSC Advances PAPER Published on 31 October 2016. Downloaded by Universitaetsbibliothek Siegen on 23/11/2016 13:07:22. View Article Online View Journal | View Issue