High Temperature Stability and Anisotropic Thermoelectricity of Monolayer Carbon Biphenylene Network

Carbon biphenylene network (C-BPN) is an ultra-thin organic material consisting of carbon atoms arranged in square-hexagonal-octagonal (4-6-8) periodic rings. Here, using the Landauer formalism in combination with first-principles calculations, we show that two-dimensional C-BPN is a highly stable material even at elevated temperatures.¹ C-BPN maintains its stability under external strain and its thermoelectric efficiency can be anisotropically engineered by tuning the strain value. Transport calculations reveal that C-BPN's transmission spectrum has significant degrees of directional anisotropy and it undergoes a metal-insulator transition under strain, which leads to an increase in its Seebeck coefficient. C-BPN's lattice thermal conductance can be selectively tuned up to 35 percent bidirectionally at room temperature by strain engineering. Enhancement in its power factor and the suppression of its lattice thermal conductance improves the p-type figure of merit up to 0.31 and 0.76 at 300 and 1000K, respectively. Our findings reveal that C-BPN has high potency to be used in thermoelectric nano devices with selective anisotropic properties at elevated temperatures.

[1] http://arxiv.org/abs/2408.14006