We are aiming to find the best two dimensional (2D) materials for thermoelectrics that convert waste heat into electricity. Despite long research in thermoelectrics, the efficiency of power conversion remains low, about 10%. Previous theory and experimental works suggest that nanomaterials can enhance thermoelectric performance. In our previous work, we found a new guiding rule that ensures thermoelectric enhancement, i.e. material confinement size (thicknesses or diameters) should be smaller than the thermal de Broglie wavelength. Two-dimensional materials satisfy this condition and might render the best thermoelectrics. Superconductivity observed in two atomic layers of carbon (twisted bilayer graphene) is a dramatic example that 2D materials can host excellent electronic properties. We believe that different species of 2D materials, such as, twisted bilayer transition metal dichalcogenides can be the best thermoelectrics that possesses tunable bandgaps and a large density of states.
Two dimensional materials, thermoelectrics
In this proposals, we are aiming to design the best thermoelectric devices based on 2D semiconductors. The single layer species can be stacked on top of another creating homo or heterobilayers. Due to this stacking, inter layer interactions dramatically change the electronic properties and as a result it should change the thermoelectrics. There are tens of monolayer species now have been fabricated and thus one can simulate almost a hundred of combination bilayers. Having this library will be very important to the progress of science and technology of thermoelectrics.
The detailed calculation can be performed numerically via density functional theory and the tight binding method. In density functional calculation we assume that the electronic states can be described by an expansion of plane waves and then the exchange and correlation energy is assumed to be functional of density. The structure relaxation and electronic structure calculations can be done with self-consistent calculation. After calculating the electronic structure the thermoelectric properties such as Seebeck coefficient, electronic and thermal conductivity from electron can be calculated using semi-classical Boltzmann transport equation.
Eddwi Hesky Hasdeo (LIPI)
Ferensa Oemry (LIPI)
Muhammad Yusrul Hanna (LIPI)
Ahmad Ridwan Tresna Nugraha (Tohoku University)
Adam Badra Cahaya (UI)
data about 1 Gb
Software: quantum espresso and fortran
Currently applying for Insinas and Toray Research Grant
10/12/2018 - 31/12/2019