Acoustic phonon recycling for photocarrier generation in graphene-WS2 heterostructures

Abstract

Electron-phonon scattering is the key process limiting the efficiency of modern nanoelectronic and optoelectronic devices, in which most of the incident energy is converted to lattice heat and finally dissipates into the environment. Here, we report an acoustic phonon recycling process in graphene-WS 2 heterostructures, which couples the heat generated in graphene back into the carrier distribution in WS 2. This recycling process is experimentally recorded by spectrally resolved transient absorption microscopy under a wide range of pumping energies from 1.77 to 0.48 eV and is also theoretically described using an interfacial thermal transport model. The acoustic phonon recycling process has a relatively slow characteristic time (>100 ps), which is beneficial for carrier extraction and distinct from the commonly found ultrafast hot carrier transfer (~1 ps) in graphene-WS 2 heterostructures. The combination of phonon recycling and carrier transfer makes graphene-based heterostructures highly attractive for broadband high-efficiency electronic and optoelectronic applications.

Giant Photoluminescence Enhancement and Carrier Dynamics in MoS2 Bilayers with Anomalous Interlayer Coupling

“…The orthogonally circularly polarized PL signals were detected by rotating the quarter-wave plate. The pump-probe system was based on a Ti: sapphire laser (1 kHz, Spectra-Physics), which was described in detail in a previous report [ 39 ]. The main power of the Ti: sapphire laser was sent to pump an optical parametric amplifier, generating tunable output energy as pump beam.…”

Polarization‐Dependent and Wavelength‐Tunable Optical Limiting and Transparency of Multilayer Selenium‐Doped Black Phosphorus

“…Here, the wavelength of the pump pulse is 400 nm, ensuring that all electrons are excited to the conduction band. The detailed dynamic process of electron transition is embodied by the time‐resolved differential reflection rate of the continuous white light probe, − Δ R / R = ( R 0 − R )/ R 0 , [ 7,80–82 ] where R 0 and R stand for the probe reflections of the sample before and after pumping, respectively; thus, Δ R is the differential signal of R which indirectly reflects changes in absorption.…”

“…Similar to other 2D materials such as graphene, [ 1–3 ] transition metal chalcogenides (TMDCs), [ 4–7 ] and topological insulators, [ 8,9 ] black phosphorus (BP) [ 10–14 ] have aroused extensive research enthusiasm in various fields. Possessing excellent properties, BP exhibits excellent potential for applications in electronics, [ 15 ] optoelectronics, [ 16–19 ] thermoelectrics, [ 20 ] photobiology, [ 21 ] etc.…”

Interfacial Strain Release from the WS2/CsPbBr3 van der Waals Heterostructure for 1.7 V Voltage All‐Inorganic Perovskite Solar Cells

“…This demonstrates that the tensile strain of the film especially in bottom region is released, which in turn reduces the strain‐induced lattice distortion [25] . Two‐dimensional WS 2 nanoflakes have a weak interaction between neighboring layers owing to the van der Waals forces, similar to the state‐of‐the‐art graphene or black phosphorus materials [26–28] . When employed as interfacial modifier, the self‐assembled WS 2 /CsPbBr 3 van der Waals heterostructure interface plays a role of lubricant between ETL and CsPbBr 3 film to help lattice expansion or shrinkage and therefore release interfacial tensile strain (Figure 2 g).…”

“…[25] Two-dimensional WS 2 nanoflakes have a weak interaction between neighboring layers owing to the van der Waals forces, similar to the state-of-the-art graphene or black phosphorus materials. [26][27][28] When employed as interfacial modifier, the self-assembled WS 2 /CsPbBr 3 van der Waals heterostructure interface plays a role of lubricant between ETL and CsPbBr 3 film to help lattice expansion or shrinkage and therefore release interfacial tensile strain (Figure 2 g). [29] Based on the optimized interfacial strain, we further evaluate the effect of WS 2 interlayer on photovoltaic performances of all-inorganic CsPbBr 3 PSCs with FTO/SnO 2 -TiO x Cl 4À2x /WS 2 /CsPbBr 3 /carbon structure (Figure 3 a).…”