Four-fold enhancement in the thermoelectric power factor of germanium selenide monolayer by adsorption of graphene quantum dot

The present study reports the electronic and thermoelectric properties of graphene quantum dot pyrene adsorbed germanium selenide monolayer using density functional theory calculations. The adsorption energy of 4x4 supercell of germanium selenide monolayer with graphene quantum dot is -0.92 eV suggesting a favorable binding between the germanium selenide monolayer and graphene quantum dot. Our calculations reveal that the Seebeck coefficient for both germanium selenide monolayer and graphene quantum dot adsorbed germanium selenide monolayer (GQD@GeSe monolayer) increases with a decrease in doping level. The value of Seebeck coefficient is highest for zero doping. The incorporation of graphene quantum dot increases the number of charge carriers in germanium selenide monolayer resulting in the amplified electrical conductivity from 0.13 x 10(19) to 0.52 x 10(19) (Omega ms)(-1) which leads to a very large thermoelectric power factor at room temperature. The power factor is enhanced from 1.17 x 10(10) to 5.38 x 10(10) W/mK in germanium selenide. The adsorption of graphene quantum dot with doping level and temperature can be used to generate more output power for the thermoelectric power generation. The present work contributes in understanding the design of germanium selenide monolayer with graphene quantum dot based hybrid structures for thermoelectric devices in the future. (C) 2020 Elsevier Ltd. All rights reserved.