Hot electron transfer in Zn–Ag–In–Te nanocrystal–methyl viologen complexes enhanced with higher-energy photon excitation

Kameyama, Tatsuya; Sugiura, Kenji; Kuwabata, Susumu; Okuhata, Tomoki; Tamai, Naoto; Torimoto, Tsukasa

doi:10.1039/d0ra02842h

Cited by 6 publications

(3 citation statements)

References 38 publications

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“…In other words, a high energy injection accelerates the relaxation process of carriers. A similar result has also been found in quantum dots and 2D films [ 51 , 52 , 53 ].…”

Section: Resultssupporting

confidence: 85%

Broadband Visible Nonlinear Absorption and Ultrafast Dynamics of the Ti3C2 Nanosheet

Shao

Chen

et al. 2020

Nanomaterials

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The Ti3C2 nanosheet, as a new two-dimensional (2D) group, has been found to have attractive characteristics as material for electromagnetic shielding and energy storage. In this study, the nonlinear broadband absorption and ultrafast dynamics of the Ti3C2 nanosheet were investigated using nanosecond open-aperture Z-scan and transient absorption techniques. The mechanism of two-photon absorption (TPA) was revealed in the visible region (475–700 nm). At lower incident energies, nonlinear absorption could not happen. When the laser energy increased to 0.64 GW/cm2, electrons in the valence band could absorb two photons and jump to the conduction band, with TPA occurring, which meant that the sample exhibited reverse saturable absorption (RSA). In addition, when transient absorption was used to investigate the ultrafast carrier dynamics of the sample, it demonstrated that the relaxation contains a fast decay component and a slow one, which are obtained from electron–phonon and phonon–phonon interactions, respectively. Moreover, with the increasing pump fluence, the fast decay lifetime τ1 increased from 3.9 to 4.5 ps, and the slow one τ2 increased from 11.1 to 13.2 ps. These results show that the Ti3C2 nanosheet has potential applications in broadband optical limiters.

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“…In other words, a high energy injection accelerates the relaxation process of carriers. A similar result has also been found in quantum dots and 2D films [ 51 , 52 , 53 ].…”

Section: Resultssupporting

confidence: 85%

Broadband Visible Nonlinear Absorption and Ultrafast Dynamics of the Ti3C2 Nanosheet

Shao

Chen

et al. 2020

Nanomaterials

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“…Ultimately, the improved efficiency of electron–phonon interaction promotes the cooling process, or in other words, it is high energy injection that speeds up electron decay. Similar properties can be seen in either quantum dots or 2D films [ 37 , 38 , 39 ].…”

Section: Resultsmentioning

confidence: 52%

Strengthened Optical Nonlinearity of V2C Hybrids Inlaid with Silver Nanoparticles

Shao

Xiang

et al. 2022

Nanomaterials

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The investigation of nonlinear optical characteristics resulting from the light–matter interactions of two-dimensional (2D) nano materials has contributed to the extensive use of photonics. In this study, we synthesize a 2D MXene (V2C) monolayer nanosheet by the selective etching of Al from V2AlC at room temperature and use the nanosecond Z-scan technique with 532 nm to determine the nonlinear optical characters of the Ag@V2C hybrid. The z-scan experiment reveals that Ag@V2C hybrids usually exhibits saturable absorption owing to the bleaching of the ground state plasma, and the switch from saturable absorption to reverse saturable absorption takes place. The findings demonstrate that Ag@V2C has optical nonlinear characters. The quantitative data of the nonlinear absorption of Ag@V2C varies with the wavelength and the reverse saturable absorption results from the two-photon absorption, which proves that Ag@V2C hybrids have great potential for future ultrathin optoelectronic devices.

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“…Moreover, the linear dependence of measured transient signals for both the systems upon excitation intensities in the studied range (5–200 μW ≈ 10 × 10 –9 to 40 × 10 –8 J/pulse) as well as exactly the same kind of decay profiles of all studied excitation intensities confirm the absence of multiexciton generation and Auger recombination processes for both the systems. Okuhata et al reported similar observations, and it was rationalized as the hot electron transfer (HET) from the 1P(e) state of CdSe QDs to Au in CdSe QD–Au heterostructures and from the Zn–Ag–In–Te nanocrystal to methyl viologen (MV 2+ ) in ZAIT NC–MV 2+ complexes . Note that no difference in transient signal strength of bare CdTe QDs and CdTe QD–TCPP 1 NCs at initial delays is observed along with no change in rise time of the 1S bleach signal when both systems were excited in the vicinity of 1S exciton absorption (see Supporting Information for more, Figure S7–S11), which again ensures that there is no electron transfer from the band-edge exciton (1S) to TCPP in CdTe QD–TCPP 1 NCs.…”

Section: Resultsmentioning

confidence: 71%

Hot Electron Transfer from CdTe Quantum Dot (QD) to Porphyrin and Ultrafast Electron Transfer from Porphyrin to CdTe QD in CdTe QD–Tetrakis(4-carboxyphenyl)porphyrin Nanocomposites

et al. 2021

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Understanding of exciton dynamics in semiconductor quantum dots (QDs) is of great importance due to their immense application potential on various photonic devices. In this work, we demonstrate hot electron transfer (HET) from higher excited states of cadmium telluride quantum dots (CdTe QDs) to tetrakis(4-carboxyphenyl)porphyrin (TCPP) and ultrafast electron transfer from photoexcited TCPP to CdTe QDs in newly prepared CdTe QD−tetrakis(4-carboxyphenyl)porphyrin nanocomposites (CdTe QD−TCPP NCs), where TCPP is noncovalently attached to CdTe QDs, by employing steady state, time-resolved emission, and femtosecond transient absorption spectroscopic techniques. The observation of efficient quenching of the photoluminescence (PL) of CdTe QDs with little/negligible change in photoluminescence (PL) decay profiles in nanosecond time regime (TCSPC method) of CdTe QD−TCPP NCs predominantly indicates static interaction between these two interacting species, CdTe QD and TCPP. Excitation wavelength and excitation intensity dependent femtosecond transient absorption studies of CdTe QDs and CdTe QD−TCPP NCs confirm the hot electron transfer (HET) from higher excited states (Σ − /1P(e)) to TCPP. Analysis of growth kinetics of band-edge or 1S bleach amplitude of band-edge bleach signal strength at the initial stage after excitation allows us to estimate 30−40% quantum efficiency (Φ HET ) of HET when CdTe QD−TCPP NCs are excited at higher excited state (∼390 nm). In contrast, no electron transfer was observed when CdTe QD−TCPP NCs are excited in the vicinity of the band-edge (1S) exciton. In another instance, femtosecond transient absorption studies upon 630 nm excitation at the Q-band of TCPP in CdTe QD−TCPP NCs suggest the occurrence of ultrafast electron transfer (<250 fs) from photoexcited TCPP to CdTe QDs in CdTe QD−TCPP NCs. The charge separation and charge recombination dynamics in CdTe QD−TCPP NCs are explored in detail. The fundamental understanding of this "to and fro" photoinduced electron transfer dynamics in CdTe QD−TCPP NCs opens up new possibilities to design an efficient light-harvesting system based on inorganic−organic hybrid systems.

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Hot electron transfer in Zn–Ag–In–Te nanocrystal–methyl viologen complexes enhanced with higher-energy photon excitation

Abstract: Zn–Ag–In–Te nanocrystals exhibited hot electron transfer to adsorbed methyl viologen, the efficiency being enhanced from 45% to 72% with an increase in the excitation photon energy.

Cited by 6 publications

References 38 publications

Broadband Visible Nonlinear Absorption and Ultrafast Dynamics of the Ti3C2 Nanosheet

Broadband Visible Nonlinear Absorption and Ultrafast Dynamics of the Ti3C2 Nanosheet

Strengthened Optical Nonlinearity of V2C Hybrids Inlaid with Silver Nanoparticles

Hot Electron Transfer from CdTe Quantum Dot (QD) to Porphyrin and Ultrafast Electron Transfer from Porphyrin to CdTe QD in CdTe QD–Tetrakis(4-carboxyphenyl)porphyrin Nanocomposites

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