Near-Infrared Optical Response and Carrier Dynamics for High Photoconversion in Tellurene

Abstract

Materials for applications in solar cells require a combination of features including an appropriate band gap and long relaxation times for photoexcited hot carriers. On the basis of ab initio many-body perturbation theory, including the spin−orbit interaction, we investigate the photocarrier generation and dynamics in α-tellurene. We show that photoexcited electrons are mainly generated in the near-infrared range, starting at 0.89 eV and forming excitons that are strongly bound, compared to its bulk counterpart, with a binding energy of 0.31 eV. We also explore the role of the electron−phonon interaction, finding that the electronic states in the first conduction band minimum couples weakly with phonons, yielding longer hot electron lifetimes (up to 70 fs) 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/cm 2 and a maximum power conversion efficiency of 4.4%, which highlights its potential for efficient photovoltaic device development.

Photovoltaic Efficiency of Transition Metal Dichalcogenides Thin Films by Ab Initio Excited-State Methods

“…Graphite is a well-known member of this family that is broadly used in industry as components for electrodes, lubricants, fibers, heat exchangers, and batteries . The experimental isolation of its single-layer counterpart, graphene has opened the way for a new era of 2D materials with compelling optoelectronic properties. − However, the lack of an energy gap in graphene greatly limits its applicability in semiconductor technologies. On the other hand, the semiconducting properties of transition metal dichalcogenides (TMDCs), with chemical formula MX 2 (M = Mo, W, and others, and X = S, Se, Te) pushed the frontier of vdW materials’ potential uses spanning a broad range of fields, including nanoelectronics and nanophotonics, sensing and actuation in the nanoscale, and photovoltaic solar cells. − …”

Elucidating the coherent and incoherent reflection of plane-waves in finite thickness media: a practical pedagogical application

“…The latter case occurs if the thickness of the film is greater than the coherent length (propagation length over which coherence is maintained), then interference effects can be disregarded and the intensity of the superposed field can be obtained simply as the sum of all waves' intensities [16,18]. Due to the relatively simple set of equations governing the optical properties within this regime, they are widely used in current renewable energy research [19][20][21][22] and yet, poorly discussed in undergraduate textbooks.…”

Optical properties enhancement via WSSe/silicene solar cell junctions

“…Since the first successful realization of graphene, the quest for 2D materials with improved physical and chemical properties has attracted considerable attention, due to their potential device applications in electronics, [1][2][3] plasmonics, 4 optoelectronics 5 and photovoltaics. [6][7][8][9] Indeed, within the novel catalog of materials, one can find semimetallic materials (silicene, [10][11][12][13][14] germanene 15 ) and semiconductors such as phosphorene, 16,17 Xenes, 18,19 and transition metal dichalcogenides (TMDCs). 20 The latter have been reported as promising materials for application in photoelectronic devices 21 due to their direct bandgap energy and large optical absorption.…”