Dynamics Of Photogenerated Carriers Research Articles

Oxygen Vacancies Trigger Rapid Charge Transport Channels at the Engineered Interface of S-scheme Heterojunction for Boosting Photocatalytic Performance.

Although oxygen vacancies (Ovs) have been intensively studied in single semiconductor photocatalysts, exploration of intrinsic mechanisms and in-depth understanding of Ovs in S-scheme heterojunction photocatalysts are still limited. Herein, a novel S-scheme photocatalyst made from WO3-Ov/In2S3 with Ovs at the heterointerface is rationally designed. The microscopic environment and local electronic structure of the S-scheme heterointerface are well optimized by Ovs. Femtosecond transient absorption spectroscopy (fs-TAS) reveals that Ovs trigger additional charge movement routes and therefore increase charge separation efficiency. In addition, Ovs have a synergistic effect on the thermodynamic and kinetic parameters of S-scheme photocatalysts. As a result, the optimal photocatalytic performance is significantly improved, surpassing that of single component WO3-Ov and In2S3 (by 35.5 and 3.9 times, respectively), as well as WO3/In2S3 heterojunction. This work provides new insight into regulating the photogenerated carrier dynamics at the heterointerface and also helps design highly efficient S-scheme photocatalysts.

Oxygen Vacancies Trigger Rapid Charge Transport Channels at the Engineered Interface of S‐scheme Heterojunction for Boosting Photocatalytic Performance

Although oxygen vacancies (Ovs) have been intensively studied in single semiconductor photocatalysts, exploration of intrinsic mechanisms and in‐depth understanding of Ovs in S‐scheme heterojunction photocatalysts are still limited. Herein, a novel S‐scheme photocatalyst made from WO3‐Ov/In2S3 with Ovs at the heterointerface is rationally designed. The microscopic environment and local electronic structure of the S‐scheme heterointerface are well optimized by Ovs. Femtosecond transient absorption spectroscopy (fs‐TAS) reveals that Ovs trigger additional charge movement routes and therefore increase charge separation efficiency. In addition, Ovs have a synergistic effect on the thermodynamic and kinetic parameters of S‐scheme photocatalysts. As a result, the optimal photocatalytic performance is significantly improved, surpassing that of single component WO3‐Ov and In2S3 (by 35.5 and 3.9 times, respectively), as well as WO3/In2S3 heterojunction. This work provides new insight into regulating the photogenerated carrier dynamics at the heterointerface and also helps design highly efficient S‐scheme photocatalysts.

Photogenerated carrier dynamics of Mn2+ doped CsPbBr3 assembled with TiO2 systems: Effect of Mn doping content.

In recent years, all-inorganic perovskite materials have become an ideal choice for new thin film solar cells due to their excellent photophysical properties and have become a research hotspot. Studying the ultrafast dynamics of photo-generated carriers is of great significance for further improving the performance of such devices. In this work, we focus on the transient dynamic process of CsPbBr3/TiO2 composite systems with different Mn2+ doping contents using femtosecond transient absorption spectroscopy technology. We used singular value decomposition and global fitting to analyze the transient absorption spectra and obtained three components, which are classified as hot carrier cooling, charge transfer, and charge recombination processes, respectively. We found that the doping concentration of Mn2+ has an impact on all three processes. We think that the following two factors are responsible: one is the density of defect states and the other is the bandgap width of perovskite. As the concentration of doped Mn2+ increases, the charge transfer time constant shows a trend of initially increasing, followed by a subsequent decrease, reaching a turning point. This indicates that an appropriate amount of Mn2+ doping can effectively improve the photoelectric performance of solar cell systems. We proposed a possible charge transfer mechanism model and further elucidated the microscopic mechanism of the effect of Mn2+ doping on the interface charge transfer process of the CsPbBr3/TiO2 solar cell system.

Influence of Hot Carrier Cooling and Band‐Filling Effect on Linewidth of Perovskite Microlasers

AbstractIn semiconductor‐based microlasers, the generated excited carriers can affect both the optical absorption coefficient and refractive index, influencing the lasing behavior and device performance. In this study, the lasing behavior of individual MAPbBr3 microrods pumped by femtosecond laser pulses is investigated using an ultrafast optical Kerr gating technique. By analyzing the spectral and temporal evolution of the lasing behavior, it is found that the band‐filling (BF) effect can cause a significant change in the refractive index of the material, which results in an unfavorable red‐shift and broadening of the resonant modes, deteriorating the laser linewidth and quality factor. The hot carrier cooling process can provide a buffer for alteration of the energy level occupation state, resulting in a small transient refractive index change and slight red‐shift. These results offer insights into the lasing behavior driven by photogenerated carrier dynamics and provide an optimization strategy for semiconductor‐based microlasers.

Broadband Artificial Tetrachromatic Synaptic Devices Composed of 2D/3D Integrated WSe2‐GaN‐based Dual‐Channel Floating Gate Transistors

AbstractThe development of artificial tetrachromatic vision holds great potential to enhance human color perception and discrimination, thereby enabling more effective navigation in diverse environments. Herein, an artificial tetrachromatic synaptic device is presented built upon 2D‐3D vertically stacked semiconductors composed of tungsten diselenide (WSe2)‐gallium nitride (GaN) configuration, forming a dual‐channel floating gate transistor (FGT). Under the concerted influence of electrical and optical stimulation, the device successfully mimics fundamental tetrachromatic synaptic behaviors, including short‐term potentiation (STP), weak long‐term potentiation (wLTP), long‐term potentiation (LTP), paired‐pulse facilitation (PPF), spike number‐dependent plasticity (SNDP), and spike rate‐dependent plasticity (SRDP). Notably, the plasticity of the device can be further modulated under ultraviolet (UV) stimulation, providing insights into the modulation of synaptic plasticity through the photogenerated carrier dynamics in the GaN channel. These results imply that WSe2‐GaN‐based FGT architecture with dual‐channel characteristics seamlessly integrates optical sensing and synaptic simulation functionalities, representing a promising avenue for the development of next‐generation artificial visual perception systems (AVPS), with a particular advantage for the pursuit of high‐performance artificial tetrachromatic neuromorphic computing applications of the future.

Broadband photodetector based on Co3O4/ZnO/Si double heterojunctions: A morphological and optoelectronic study

The growing demand for efficient and cost-effective optoelectronic devices has motivated extensive research into advanced photodetector architectures. This work realizes a robust platform for broadband photodetection via architectural engineering of Co3O4/ZnO/Si double heterojunctions using facile chemical spray pyrolysis. Comprehensive materials and device characterization provides fundamental insights into the role of tailored morphology, band alignment engineering, and defect landscape in dictating device behavior. Aligned ZnO nanorods and fine-grained Co3O4 layers enable efficient light harvesting and charge transport. A triple bandgap structure stemming from the synergistic combination of the two oxides facilitates broadband spectral response from 400 to 1000 nm. Based on the optical properties, triple energy bandgap ranges have been observed, ZnO exhibits an energy bandgap ranging from 2.35 eV to 3.15 eV, while Co3O4 shows energy bandgaps in the range of 1.85 eV–2.23 eV and 1.35 eV–1.5 eV. The responsivity measurements show that Co3O4/ZnO/Si double-heterojunction device has the highest responsivity over a wide range, with distinct peaks at 480 nm and 950 nm, reaching values of 3.5 A/W and 4.5 A/W, respectively. Analysis of electrical transport characteristics and energy band diagrams elucidates the photogenerated carrier dynamics and photocurrent generation governed by strategic heterointerfaces. These fundamental insights into nanoscale interface and architecture engineering lay the foundation for custom-designing high performance metal oxide heterojunction photodetectors through facile and scalable spray pyrolysis technique.

Photo-Generated Charge Carrier Dynamics in Metal Oxide Photocatalysts

Solar water splitting is one of the most attractive energy carrier generation processes to utilize solar energy. Light generated hydrogen is a clean energy carrier, since their consumption for energy generation produces only water. Moreover, generated hydrogen can be stored and used whenever required. Hydrogen is mostly used as a feedstock in the chemical and petrochemical industries, e.g. production of ammonia, methanol and fertilisers.[1]The photocatalytic solar water splitting process has been studied extensively over the last half century. However, despite the efforts, no ideal photocatalyst has yet been identified to meet three main requirements for commercialisation: (1) low cost, (2) high solar to hydrogen (STH) efficiency and (3) durability. Over the last two decades, considerable efforts have focused on developing visible light active photocatalysts, and some promising photocatalysts with relatively high water splitting efficiency were discovered.[2] In contrast to search of appropriate photocatalyst (nano)materials, mechanisms of photocatalytic water splitting reactions, in particular charge carrier dynamics of photocatalysts, were little studied. Understanding charge carrier dynamics in photocatalysts will certainly provide an opportunity to design high efficiency photocatalysts.In this presentation, we will show dynamics of photo-generated charge carries in metal oxide photocatalyst by employing a series of transient absorption spectroscopies covering from 150 fs to 100 s over UV-VIS-NIR wavelength ranges.[2] Correlation of the charge carrier dynamics with photocatalysis reactions will be discussed.This work was partly supported by ARC DP fund (DP180103815) and ARC LIEF funds (LE170100235 and LE200100051), Australia, and the Collaborative Research Program of Institute for Chemical Research, Kyoto University (grant number 2023-45 and 2022-99), Japan. We also acknowledge supports from School of Engineering, RMIT University, and Forefront Research Center, Faculty of Science, Osaka University.

Insights into Photogenerated Carrier Dynamics and Overall Water Splitting of the CrS3/GeSe Heterostructure.

Based on the nonadiabatic molecular dynamics (NAMD) simulations and the first-principles calculations, we explore the overall water-splitting schemes and the photogenerated carrier dynamics for two configurations (CG and CyG) of the CrS3/GeSe van der Waals heterostructures. The photocatalytic direct Z-schemes and carrier migration pathways for hydrogen and oxygen evolution reactions (HER/OER) are constructed based on the electronic properties. The solar-to-hydrogen efficiency (η'STH values) of the schemes can reach 10.60% and 10.17% and further rise under tensile strain. The NAMD results demonstrate similar transfer times of the electron/hole for HER/OER and more rapid electron-hole recombination in CG enables it to be superior to CyG in photocatalytic performance. Moreover, the Gibbs free energy indicates that both the HERs and OERs turn to spontaneously proceed with CG and CyG at pH = 0-12.37 and pH = 2.55-11.01, respectively. These facts reveal that the CrS3/GeSe heterostructure is promising in photocatalytic overall water splitting.

In-situ formation of SrTiO3/Ti3C2 MXene Schottky heterojunction for efficient photocatalytic hydrogen evolution

Surface and interface engineering of composite photocatalysts are effective ways to enhance the dynamics of photo-generated charge carriers. In this work, SrTiO3/Ti3C2 MXene (STO/TC) Schottky heterojunction is constructed by in-situ growth of SrTiO3 (STO) on Ti3C2 MXene (TC) through Sr(OH)2 etching the surfaces of TC. This in-situ growth strategy not only creates the tight chemically bonded interfaces by SrTiO3 nanoparticles uniformly anchoring on the surface of two-dimensional Ti3C2 MXene nanosheets for promoting the photo-generated charge carrier separation, but also introduces surface Ti vacancies as the efficient catalytic active sites to accelerate the charge carrier transfer process for efficient hydrogen production. The photocatalytic system constructed by interface and surface engineering optimizes the photo-generated charge carrier dynamics and refines the photocatalytic hydrogen evolution performance (6.8 times higher than pristine SrTiO3) and stability. This work is expected to provide an alternative strategy to construct highly efficient photocatalysts with hydrogen evolution.

The open core-shell TiO2@ZnIn2S4 step-scheme heterojunction to enhance mass transfer and light utilization for efficient photocatalytic performance

Open shell-core structure is crucial for light absorption, photogenerated carrier dynamics and mass transfer in photocatalytic processes. However, the preparation of open shell-core structures is rarely reported. Hence, ZnIn2S4 hemisphere-wrapped TiO2 nanoparticles (Ti-ZIS) shell-core heterojunctions were successfully prepared through a N, N-Dimethylformamide (DMF)-assisted solvothermal process for outstanding photocatalytic performances. Among them, CO gas generated by DMF decomposition helps ZIS to form hollow structure, while TiO2 nanoparticles are generated based on the interference of dimethylamine generated by DMF decomposition with its crystal growth. The research show that the shell-core structure increases the specific surface area (124.9 m2/g), shorten the migration distance of electron and hole pairs, and promotes light absorption. Additionally, the transfer process of photogenerated carriers have been changed and accelerated via the built-in electric field, thereby enhancing the photocatalytic reaction. The experimental results show that the Ti-ZIS shell-core heterojunction exhibits excellent photocatalytic hydrogen evolution (28.0 mmol/h/g with Pt as cocatalyst and 7.4 mmol/h/g without cocatalyst) than those of other state-of-the-art ZIS-based noble metal or without cocatalysts reported recently, and lignin degradation (76.7% within 120 min). The removal rates of chemical oxygen demand (COD) and total organic carbon (TOC) are 72.1% and 49.4%, respectively.

Electric double layer-mediated polarization field for optimizing photogenerated carrier dynamics and thermodynamics

Photocatalytic hydrogen evolution efficiency is limited due to unfavorable carrier dynamics and thermodynamic performance. Here, we propose to introduce electronegative molecules to build an electric double layer (EDL) to generate a polarization field instead of the traditional built-in electric field to improve carrier dynamics, and optimize the thermodynamics by regulating the chemical coordination of surface atoms. Based on theoretical simulation, we designed CuNi@EDL and applied it as the cocatalyst of semiconductor photocatalysts, finally achieved a hydrogen evolution rate of 249.6 mmol h−1 g−1 and remained stable after storing under environmental conditions for more than 300 days. The high H2 yield is mainly due to the perfect work function, Fermi level and Gibbs free energy of hydrogen adsorption, improved light absorption ability, enhanced electron transfer dynamics, decreased HER overpotential and effective carrier transfer channel arose by EDL. Here, our work opens up new perspectives for the design and optimization of photosystems.

Strongly luminescent and highly stable CsPbBr3/Cs4PbBr6 core/shell nanocrystals and their ultrafast carrier dynamics

All-inorganic lead halide perovskites nanocrystals (NCs) have been demonstrated to be promising candidates for optoelectronic devices, but preparing perovskite NCs with high photoluminescence quantum yields (PLQYs) and excellent stability has been a challenge. In this work, CsPbBr3/Cs4PbBr6 core/shell NCs with a PLQYs of 87.23% and long-term stability in ambient environments was prepared by room temperature inverse microemulsion method. The excellent stability of the sample was attributed to the protection of Cs4PbBr6, and higher PLQYs could be owing to the passivation effect of the core/shell structure. To illustrate the distribution of photogenerated carrier in the core/shell structure, a confined excitons model was proposed based on time-resolved PL and temperature dependent PL measurements. Femtosecond time-resolved transient absorption spectra measurements were performed upon different excitation wavelength to unveil the photogenerated carrier dynamics in core/shell NCs. Upon 300 nm excitation, a carrier transfer process with the time of 3.18 ps from shell to core layer was observed. Furthermore, both two- and three-photon absorption PL was discovered in core/shell NCs, further verifying the carrier transfer process.

Observation of photoinduced polarons in semimetal 1T-TiSe2

In this work, ultrafast carrier dynamics of mechanically exfoliated 1T-TiSe2 flakes from the high-quality single crystals with self-intercalated Ti atoms are investigated by femtosecond transient absorption spectroscopy. The observed coherent acoustic and optical phonon oscillations after ultrafast photoexcitation reveal the strong electron–phonon coupling in 1T-TiSe2. The ultrafast carrier dynamics probed in both visible and mid-infrared regions indicate that some photogenerated carriers localize near the intercalated Ti atoms and form small polarons rapidly within several picoseconds after photoexcitation due to the strong and short-range electron–phonon coupling. The formation of polarons leads to a reduction of carrier mobility and a long-time relaxation process of photoexcited carriers for several nanoseconds. The formation and dissociation rates of the photoinduced polarons are dependent on both the pump fluence and the thickness of TiSe2 sample. This work offers new insights into the photogenerated carrier dynamics of 1T-TiSe2, and emphasizes the effects of intercalated atoms on the electron and lattice dynamics after photoexcitation.

Excitation-Wavelength-Dependent Charge-Carrier Lifetime in Hematite: An Insight from Nonadiabatic Molecular Dynamics.

Experiments have reported that the photoexcited carrier lifetime in α-Fe2O3 has a significant excitation-wavelength dependence but leave the physical mechanism unresolved. In this work, we rationalize the puzzling excitation-wavelength dependence of the photoexcited carrier dynamics in Fe2O3 by performing nonadiabatic molecular dynamics simulation based on the strongly constrained and appropriately normed functional, which accurately describes the electronic structure of Fe2O3. Photogenerated electrons with lower-energy excitation relax fast in the t2g conduction band within about 100 fs, while the photogenerated electrons with higher-energy excitation undergo first a slower interband relaxation from the eg lower state to the t2g upper state on a time scale of 135 ps, followed by the much faster t2g intraband relaxation. This study provides insight into the experimentally reported excitation-wavelength dependence of the carrier lifetime in Fe2O3 and a reference for regulating photogenerated carrier dynamics in transition-metal oxides through the light excitation wavelength.

Broadband ultrafast photogenerated carrier dynamics induced by intrinsic defects in <inline-formula><tex-math id="Z-20231102113631">\begin{document}$\boldsymbol\beta$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="21-20231173_Z-20231102113631.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="21-20231173_Z-20231102113631.png"/></alternatives></inline-formula>-Ga<sub>2</sub>O<sub>3</sub>

The ultra-wide bandgap semiconductor gallium oxide <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> with enhanced resistance to the irradiation and temperature is favorable for high-power and high-temperature optoelectronic devices. <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> also exhibits great potential applications in the field of integrated photonics because of its compatibility with the CMOS technique. However, a variety of intrinsic and extrinsic defects and trap states coexist in <i>β</i>-Ga<sub>2</sub>O<sub>3</sub>, including vacancies, interstitials, and impurity atoms. The defect-related carrier dynamics in <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> not only adversely affect the optical and electrical properties, but also directly limit the performance of <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> based devices. Therefore, a comprehensive understanding of the carrier transportation and relaxation dynamics induced by intrinsic defects is very important. Supercontinuum-probe spectroscopy can provide a fruitful information about the carrier relaxation processes in different recombination mechanisms, and thus becomes an effective way to study the defect dynamics. In this work, we study the dynamics of carrier trapping and recombination induced by intrinsic defects in pristine <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> crystal by using wavelength-tunable ultrafast transient absorption spectroscopy. The broadband absorption spectra induced by the intrinsic defects are strongly dependent on the polarization of pump pulse and probe pulse. Particularly, two absorption peaks induced by the two defect states can be extracted from the transient absorption spectra by subtracting the absorption transients under two probe polarizations. The observed defect-induced absorption features are attributed to the optical transitions from the valence band to the different charge states of the intrinsic defects (such as gallium vacancy). The data are well explained by a proposed carrier capture model based on multi-level energies. Moreover, the hole capture rate is found to be much greater than that of the electron, and the absorption cross-section of the defect state is at least 10 times larger than that of free carrier. Our findings not only clarify the relationship between intrinsic defects and photogenerated carrier dynamics, but also show the importance in the application of <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> crystals in ultrafast and broadband photonics.

Photogenerated carrier dynamics at the B4C3/g-C3N4 interface.

Developing van der Waals (vdW) heterostructures is an excellent approach for optimizing exceptional optoelectronic and photocatalytic properties of materials; therefore, researching the interface dynamics of charge carriers at the two-dimensional vdW heterojunction is of great significance. In this work, we perform time-dependent ab initio non-adiabatic molecular dynamics simulations to study the dynamics of charge transfer at the B4C3/g-C3N4 heterostructure. The simulations show that the charge transfer between B4C3/g-C3N4 layers is mainly caused by the non-adiabatic mechanism. The non-adiabatic mechanism leads to a higher charge-transfer efficiency and slows down the process of interlayer electron-hole recombination, thereby promoting the separation of photogenerated electron-hole pairs. Our investigation provides essential insights into understanding the dynamics of charge transfer for the B4C3/g-C3N4 heterostructure, which provides guidance for photocatalytic water splitting and optoelectrical applications.

Effect of alloying on the carrier dynamics in high-performance perovskite solar cells

High-efficiency solar cells often require light absorbers prepared from alloys, such as CdTe1−xSex, CuInxGa1−xSe2, Cu2ZnSnS4−xSex, and (CsxFA1−x)Pb(I1−yBry)3. However, how alloying affects solar cell performance is poorly understood, and determining common features associated with alloying is of significant interest. Herein, we studied the correlation between the A/X site compositional ratio and the photo-generated carrier dynamics using mixed halide perovskites (CsxFA1−x)Pb(IyBr1−y)3 as examples. Nonadiabatic molecular dynamics calculations demonstrated that charge carrier recombination is highly sensitive to the compositional ratio at the A/X-site. The enhanced lifetime is attributable to the suppression of atomic fluctuations, the weakening of electron-phonon coupling, and a reduction in the electron-transition probability between band edges. The optimal Br concentration was determined to be ∼18%, in agreement with experimental observations. This study not only advances our understanding of why mixed perovskites usually exhibit superior experimental photoelectric properties, but also provides a route for optimizing the carrier lifetimes and efficiencies of perovskite solar cells.

Ultrafast Terahertz Complex Conductivity Dynamics of Layered MoS2 Crystal Probed by Time-Resolved Terahertz Spectroscopy

Ultrafast carrier dynamics, including the carrier photoexcitation and relaxation processes, plays an essential role in improving the performance of molybdenum disulfide (MoS2)-based optoelectronic devices. Herein, we investigate the photo-generated carrier dynamics in layered MoS2 crystal using a time-resolved terahertz (THz) spectroscopy. We have analyzed the ultrafast changes of the THz complex photoconductivity deduced from the peak and zero-crossing of THz waveforms. The decay time of the real part of the THz photoconductivity in layered MoS2 crystal is independent with the pump power, while the imaginary part increases with the pump power. We attribute the decay time of the real part to the carrier recombination process via phonon-assistance and the decay time of the imaginary part to the defect-assisted exciton recombination. The peak values of the complex photoconductivity show a trend of saturation with the increase of the pump power because of the many-body effect at high carrier concentration. This work deepens the understanding of the basic ultrafast physical process in MoS2 crystal, which is enlightening for the design of novel optoelectronic devices.

Charge carrier mapping for Z-scheme photocatalytic water-splitting sheet via categorization of microscopic time-resolved image sequences

Photocatalytic water splitting system using particulate semiconductor materials is a promising strategy for converting solar energy into hydrogen and oxygen. In particular, visible-light-driven ‘Z-scheme’ printable photocatalyst sheets are cost-effective and scalable. However, little is known about the fundamental photophysical processes, which are key to explaining and promoting the photoactivity. Here, we applied the pattern-illumination time-resolved phase microscopy for a photocatalyst sheet composed of Mo-doped BiVO4 and Rh-doped SrTiO3 with indium tin oxide as the electron mediator to investigate photo-generated charge carrier dynamics. Using this method, we successfully observed the position- and structure-dependent charge carrier behavior and visualized the active/inactive sites in the sheets under the light irradiation via the time sequence images and the clustering analysis. This combination methodology could provide the material/synthesis optimization methods for the maximum performance of the photocatalyst sheets.

Heterointerface-Enhanced Ultrafast Optical Switching via Manipulating Metamaterial-Induced Transparency in a Hybrid Terahertz Graphene Metamaterial.

We have demonstrated the active manipulation of metamaterial-induced transparency (MIT) in a terahertz hybrid metamaterial with graphene overlayer under photoexcitation. It is found that the introduction of graphene can greatly modify the resonant dips and transparency window through the formed depolarization field around unequal-length double bars to weaken dipole resonances and their destructive interference. Transient control of MIT behaviors is determined by the photogenerated carrier dynamics, which influences the distributions of currents and electric fields in the resonant region to hinder the near-field coupling of two bright modes. Optical modulation depth is sensitive to bar spacing due to an anomalous increased double-bar coupling involving intracell and intercell interaction. Heterointerface formed by the added graphene with substrate could further enhance terahertz response via effective separation of the photoexcited carriers. Theoretical calculation based on the coupled Lorentz oscillator model reveals that the photoinduced terahertz response mainly originates from the coupling and damping in hybrid structures. Our findings could facilitate the development of graphene-based dynamical terahertz modulators and optoelectronic devices.