Enhancing the Sensing Performance of Zigzag Graphene Nanoribbon to Detect NO, NO, and NH Gases.

In this article, a zigzag graphene nanoribbon (ZGNR)-based sensor was built utilizing the Atomistic ToolKit Virtual NanoLab (ATK-VNL), and used to detect nitric oxide (NO), nitrogen dioxide (NO), and ammonia (NH). The successful adsorption of these gases on the surface of the ZGNR was investigated using adsorption energy (E), adsorption distance (D), charge transfer (∆Q), density of states (DOS), and band structure. Among the three gases, the ZGNR showed the highest adsorption energy for NO with -0.273 eV, the smallest adsorption distance with 2.88 Å, and the highest charge transfer with -0.104 e. Moreover, the DOS results reflected a significant increase of the density at the Fermi level due to the improvement of ZGNR conductivity as a result of gas adsorption. The surface of ZGNR was then modified with an epoxy group (-O-) once, then with a hydroxyl group (-OH), and finally with both (-O-) and (-OH) groups in order to improve the adsorption capacity of ZGNR. The adsorption parameters of ZGNR were improved significantly after the modification. The highest adsorption energy was found for the case of ZGNR-O-OH-NO with -0.953 eV, while the highest charge transfer was found for the case of ZGNR-OH-NO with -0.146 e. Consequently, ZGNR-OH and ZGNR-O-OH can be considered as promising gas sensors for NO and NO, respectively

First principle investigation of H2Se, H2Te and PH3 sensing based on graphene oxide

Detecting toxic gases is of great importance to protect our health and preserve the quality of life. In this work, graphene (G) and graphene oxide with three different modifications (G–O, G–OH, and G–O–OH) have been used to detect hydrogen selenide (H2Se), hydrogen telluride (H2Te), and phosphine (PH3) molecules based on Atomistic ToolKit Virtual NanoLab (ATK-VNL) package. The adsorption energy (Eads), adsorption distance (D), charge transfer (ΔQ), density of states (DOS), and band structure have been investigated to confirm the adsorption of H2Se, H2Te, and PH3 on the surface of G, G–O, G–OH, and G–O–OH systems. The results of G revealed highest Eads for the case of H2Te with −0.143 eV. After the functionalization of G surface, the adsorption parameters reflected an improvement due to the presence of the functional groups. Particularly, the highest adsorption energy was found between G–O system and H2Se gas with Eads of −0.319 eV. The smallest adsorption distance was found between G–OH system and H2Se gas. The highest charge transfer was found for the case of H2Se gas adsorbed on G–O–OH system. By thorough comparison of the adsorption energy, adsorption distance, and charge transfer between G, G–O, G–OH, and G–O–OH systems and the three gases, G–O–OH system can be considered as a potential sensor for H2Se gas.The publication of this article was funded by the Qatar National Library