Time-Domain Ab Initio Insights into the Reduced Nonradiative Electron–Hole Recombination in ReSe₂/MoS₂ van der Waals Heterostructure

Abstract

Two-dimensional (2D) ReSe2 has attracted considerable interest due to its unique anisotropic mechanical, optical, and exitonic characteristics. Recent transient absorption experiments demonstrated a prolonged lifetime of photoexcited charge carriers by stacking ReSe2 with MoS2, but the underlying mechanism remains elusive. Here, by combining time-domain density functional theory with nonadiabatic molecular dynamics, we investigate the electronic properties and charge carrier dynamics of 2D ReSe2/MoS2 van der Waals (vdW) heterostructure. ReSe2/MoS2 has a type II band alignment that exhibits spatially distinguished conduction and valence band edges, and a built-in electric field is formed due to interface charge transfer. Remarkably, in spite of the decreased band gap and increased decoherence time, we demonstrate that the photocarrier lifetime of ReSe2/MoS2 is ∼5 times longer than that of ReSe2, which originates from the greatly reduced nonadiabatic coupling that suppresses electron–hole recombination, perfectly explaining the experimental results. These findings not only provide physical insights into experiments but also shed light on future design and fabrication of functional optoelectronic devices based on 2D vdW heterostructures.

Common Defects Accelerate Charge Carrier Recombination in CsSnI3 without Creating Mid-Gap States

“…The nonradiative e–h recombination is governed by the electronic energy gap, the NAC, and quantum coherence between the initial and final states. − The CsSnI 3 bandgap obtained in the calculation, Figure , agrees with the experimental value of 1.3 eV. The defects introduce little change to the bandgap.…”

Identifying the Intermediate Free-Carrier Dynamics Across the Charge Separation in Monolayer MoS2/ReSe2 Heterostructures

“…As can be seen in the figure, the projected band structure of the MoS 2 /ReSe 2 shows a type II band alignment in which the conduction band minimum (CBM) and the valence band maximum (VBM) are contributed by MoS 2 (blue) and ReSe 2 (red), consistent with the recent report. 66 The CBM of the MoS 2 is about 1 eV lower than that of the ReSe 2 , which means that the electron prefers residing in the MoS 2 upon optical excitation, whereas the holes are more likely to stay in the ReSe 2 due to higher VBM. Owing to the interlayer vdW coupling, the conduction (valence) bands of the ReSe 2 and the MoS 2 are hybridized.…”

“…41 Recent reports, however, have demonstrated that there is no pronounced intermediate delocalized state, such as free electron−hole plasma during the CT in WSe 2 /WS 2 heterobilayers. 51 Compared with conventional prototyped systems, such as MoS 2 /WS 2 and WSe 2 /WS 2 , only a few works 32,66 have addressed the photocarrier dynamics of ReSe 2 /MoS 2 heterostructures, and the relaxation pathway across the charge separation is particularly unclear.…”

Multiple Heterojunction System of Boron Nitride‐Graphene/Black Phosphorene as Highly Efficient Solar Cell

“…[7] Moreover, the heterojunctions can usually overcome the shortcomings of pure single components while maintaining their inherent excellent photoelectric properties, thereby obtaining more excellent performance. [8][9][10][11] Therefore, in order to exploit solar energy more effectively, we mainly focus on the design of XSC by constructing heterojunctions.…”