Optical Response and Hot Carrier Dynamics simulations for High Photoconversion in monolayers of Tellurene

An appropriate band gap and long relaxation times for photoexcited hot carriers are some of the features required from a good candidate for photovoltaic applications. In this talk, using of ab initio many-body perturbation theory, including the spin–orbit interaction, we investigate the photocarrier generation and dynamics in α-Tellurene [1]. We show that photoexcited electrons are mainly generated in the near-infrared range, forming excitons that are strongly bound, compared to its bulk counterpart. We also explore the role of the electron–phonon and electron-electron interactions in the relaxation of charged carriers. We find that the electronic states in the first conduction band minimum couple weakly with phonons, yielding longer hot electron lifetimes, and mean free paths up to 37 nm. We also show that the extraction of hot holes may result in a challenging task as these carriers possess sub-3 nm mean free paths. We finally estimate that 1-nm-thick α-Te provides a short-circuit current density of 6.7 mA/cm² and a maximum power conversion efficiency of 4.4%, comparable to other layered materials, which highlights its potential for efficient photovoltaic device development.

[1] C. E. P. Villegas and A. R. Rocha, J. Phys. Chem. C 2022, 126, 14, 6129–6134 (2022).