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Description
Transition metal dichalcogenides (TMDCs) comprise a class of layered materials highly attractive for optoelectronics due to their scalability and thickness-dependent electrical and optical properties. While significant attention has been given to single layer TMDCs, a rather limited number of works have accurately addressed the optoelectronic properties of the few-layer case. In this work, we study the electronic and optical properties of bulk 2H group–VIB TMDCs with general formula MX$_{2}$, where M is Mo or W, and X is S or Se. We employ state-of-the-art many-body perturbation theory (MBPT) framework to compute the quasiparticle properties and optical absorption spectra including the electron–hole interaction. The obtained fundamental band gaps are indirect, as expected for bulk TMDCs, in excellent agreement with experimental electronic band gaps. The BSE optical absorption spectra describe quite accurately all the main features verified in the experimental data, with exciton peaks well-described for all the analysed TMDs. Finally, we estimate the theoretical photovoltaic performance of the group–VIB TMDCs calculating the short-circuit current, open-circuit voltage and power conversion efficiency within the spectroscopic limited maximum efficiency (SLME) framework. Those values can be used as upper limits for the power conversion efficiency of TMDCs thin films.
