Control of Charge Carrier Relaxation at the Au/WSe₂ Interface by Ti and TiO₂ Adhesion Layers: Ab Initio Quantum Dynamics

Abstract

Phonon-mediated charge relaxation plays a vital role in controlling thermal transport across an interface for efficient functioning of two-dimensional (2D) nanostructured devices. Using a combination of nonadiabatic molecular dynamics with real-time time-dependent density functional theory, we demonstrate a strong influence of adhesion layers at the Au/WSe 2 interface on nonequilibrium charge relaxation, rationalizing recent ultrafast time-resolved experiments. Ti oxide layers (TiO x ) create a barrier to the interaction between Au and WSe 2 and extend hot carrier lifetimes, creating benefits for photovoltaic and photocatalytic applications. In contrast, a metallic Ti layer accelerates the energy flow, as needed for efficient heat dissipation in electronic devices. The interaction of metallic Ti with WSe 2 causes W−Se bond scissoring and pins the Fermi level. The Ti adhesion layer enhances the electron−phonon coupling due to an increased density of states and the light mass of the Ti atom. The conclusions are robust to presence of typical point defects. The atomic-scale ab initio analysis of carrier relaxation at the interfaces advances our knowledge in fabricating nanodevices with optimized electronic and thermal properties.

Zeno and Anti-Zeno Effects in Nonadiabatic Molecular Dynamics

“…In contrast, the observables in the SMF and DISH methods are obtained directly from the stochastic TD-SE. The DISH method is widely used to model excited state dynamics in a broad range of systems. − …”

Ab Initio Quantum Dynamics Simulation of the Impact of Graphene on the Carrier Lifetime of the ZnV2O6 Photocatalyst

“…The NAC reported is not only determined by atomic velocity but also depends on energy gap and wave function overlap; the C and O atoms in the system produce strong NAC. 49 We determined the degree to which quantum decoherence affects the carrier lifetime in both the heterostructure and the single layer as well as how quickly it generates quantum decoherence states. We must first take into consideration elastic and inelastic scattering in order to comprehend the formation of decoherence.…”

“…The nuclear velocity and the components of the electron–phonon coupling matrix affect the NAC strength. We estimated the NAC between electronic states, which is defined as follows d j k = prefix− i ℏ ⟨ ϕ j ∼ false( r ; R false) false| ∇ R false| ϕ k ∼ false( r ; R false) ⟩ • Ṙ = prefix− i ℏ ⟨ ϕ j ∼ false( r ; R false) true| ∂ ∂ t true| ϕ k ∼ false( r ; R false) ⟩ The corresponding wave functions for the electronic states i and j are among φ i ,φ i ; and Ṙ represents nuclear velocity.…”

“…The greater contribution of graphene at higher energies is due to the higher NAC above the Fermi level (Figure ). The NAC reported is not only determined by atomic velocity but also depends on energy gap and wave function overlap; the C and O atoms in the system produce strong NAC …”

Lattice Distortion and Low-Frequency Anharmonic Phonons Suppress Charge Recombination in Lead Halide Perovskites upon Pseudohalide Doping: Time-Domain Ab Initio Analysis

“…The charge recombination dynamics were investigated using the decoherence-induced surface hopping (DISH) technique, which includes the loss of coherence within the electronic system due to coupling to quantum phonons. , The decoherence time is estimated as the pure dephasing time using the optical response theory. , In order to further reduce the computational cost, classical path approximation (CPA) was used, in which the atomic dynamics were assumed to be weakly dependent on the quantum state of the electronic subsystem, as compared to thermal atomic fluctuations. This methodology has already been widely applied to study excited-state dynamics in a broad range of systems, including perovskites. − …”