Influence of defect and doping on graphene for sensing of nitrogen oxide: first principle analysis

This paper analyzes graphene as a gas sensor to detect toxic nitrogen oxide (NO) gas by modifying the graphene surface with different doping and defects. Generally, dopants and defects are considered as material imperfection which degrade their performance. However, at the nanoscale level, they enhance material functionality for device applications. In this work, pristine, single vacancy defective, and transition metals (copper, gold, platinum) doped graphene sheets are explored as NO sensing materials. The sensing mechanism is assessed based on the electronic nature, charge transfer, adsorption energy, electrical properties (I-V), and sensitivity. The result shows that defective graphene has the highest adsorption energy of -3.191 eV and 56% sensitivity. However, this extremely strong chemisorption renders the sensor practically irreversible at room temperature, limiting its reusability. In contrast, platinum doped graphene has the highest sensitivity of 143% with lower adsorption energy of -1.970 eV, suggesting better suitability for practical gas sensor. Thus, the work presents a framework for the development of high-performance graphene-based gas sensor using targeted material engineering, specifically through doping and defect engineering.