Tuning thermoelectric efficiency of polyaniline sheet by strain engineering

Two-dimensional polyaniline monolayer (C3N) has been recently synthesized as an indirect semiconductor with high electron mobility. In this research, with combination of density functional theory and Green function formalism, we investigate electrical and thermal properties of C3N sheet in details. It is observed that a tensile strain along zigzag direction can induce a transition from indirect to direct semiconductor, whereas the sheet transits from semiconductor to metal under compressive strain. Thermoelectric efficiency of unstretched C3N sheet is higher in p-doping and its maximum value is obtained when the transport is along zigzag direction. A reduction in figure of merit is found upon applying strain independent from its direction. To overcome the reduction, we show that when the electrical transport and strain are perpendicular to each other, thermoelectric efficiency of the C3N sheet can be significantly increased dependent on the kind of strain (tensile or compression). Results predict the potential application of C3N sheet in thermoelectric and optoelectronic industry by strain engineering.