scholarly journals Ab Initio Simulation of Attosecond Transient Absorption Spectroscopy in Two-Dimensional Materials

2018 ◽  
Vol 8 (10) ◽  
pp. 1777 ◽  
Author(s):  
Shunsuke Sato ◽  
Hannes Hübener ◽  
Umberto De Giovannini ◽  
Angel Rubio
Keyword(s):  
Absorption Spectroscopy ◽  
Density Functional ◽  
Transient Absorption ◽  
Hexagonal Boron Nitride ◽  
Laser Pulses ◽  
Transient Absorption Spectroscopy ◽  
Band Model ◽  
Two Dimensional ◽  
Energy Bands ◽  
Two Dimensional Materials

We extend the first-principles analysis of attosecond transient absorption spectroscopy to two-dimensional materials. As an example of two-dimensional materials, we apply the analysis to monolayer hexagonal boron nitride (h-BN) and compute its transient optical properties under intense few-cycle infrared laser pulses. Nonadiabatic features are observed in the computed transient absorption spectra. To elucidate the microscopic origin of these features, we analyze the electronic structure of h-BN with density functional theory and investigate the dynamics of specific energy bands with a simple two-band model. Finally, we find that laser-induced intraband transitions play a significant role in the transient absorption even for the two-dimensional material and that the nonadiabatic features are induced by the dynamical Franz–Keldysh effect with an anomalous band dispersion.

scholarly journals Manipulation of hot carrier cooling dynamics in two-dimensional Dion–Jacobson hybrid perovskites via Rashba band splitting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jun Yin ◽  
Rounak Naphade ◽  
Partha Maity ◽  
Luis Gutiérrez-Arzaluz ◽  
Dhaifallah Almalawi ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Phonon Scattering ◽  
Transient Absorption Spectroscopy ◽  
Band Model ◽  
Two Dimensional ◽  
Spintronic Devices ◽  
Hot Carrier ◽  
Band Splitting ◽  
Perovskite Materials ◽  
Spin Polarized

AbstractHot-carrier cooling processes of perovskite materials are typically described by a single parabolic band model that includes the effects of carrier-phonon scattering, hot phonon bottleneck, and Auger heating. However, little is known (if anything) about the cooling processes in which the spin-degenerate parabolic band splits into two spin-polarized bands, i.e., the Rashba band splitting effect. Here, we investigated the hot-carrier cooling processes for two slightly different compositions of two-dimensional Dion–Jacobson hybrid perovskites, namely, (3AMP)PbI4 and (4AMP)PbI4 (3AMP = 3-(aminomethyl)piperidinium; 4AMP = 4-(aminomethyl)piperidinium), using a combination of ultrafast transient absorption spectroscopy and first-principles calculations. In (4AMP)PbI4, upon Rashba band splitting, the spin-dependent scattering of hot electrons is responsible for accelerating hot-carrier cooling at longer delays. Importantly, the hot-carrier cooling of (4AMP)PbI4 can be extended by manipulating the spin state of the hot carriers. Our findings suggest a new approach for prolonging hot-carrier cooling in hybrid perovskites, which is conducive to further improving the performance of hot-carrier-based optoelectronic and spintronic devices.

scholarly journals Widely tunable cavity-enhanced ultrafast spectroscopy

2019 ◽  
Vol 205 ◽  
pp. 01024
Author(s):  
Myles C. Silfies ◽  
Yuning Chen ◽  
Henry Timmers ◽  
Abijith S. Kowligy ◽  
Alex Lind ◽  
...  
Keyword(s):  
Gas Phase ◽  
Absorption Spectroscopy ◽  
Ultrafast Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Two Dimensional ◽  
Frequency Combs ◽  
Gas Phase Clusters ◽  
Uv Visible ◽  
Tunable Frequency

Generation of widely tunable frequency combs in the UV, visible, and infrared is discussed for use in cavity-enhanced transient absorption spectroscopy on gas-phase clusters. Progress towards cavity-enhanced two-dimensional spectroscopy is also presented.

scholarly journals Investigation of different photochemical reactions of avobenzone derivatives by ultrafast transient absorption spectroscopy

2019 ◽  
Vol 18 (12) ◽  
pp. 3000-3007
Author(s):  
Jialin Wang ◽  
Yibo Lei ◽  
Yan Guo ◽  
Junxiao Wang ◽  
Jiani Ma
Keyword(s):  
Absorption Spectroscopy ◽  
Photochemical Reaction ◽  
Density Functional ◽  
Transient Absorption ◽  
Density Functional Theory Calculations ◽  
Photochemical Reactions ◽  
Transient Absorption Spectroscopy ◽  
Functional Theory ◽  
Ultrafast Transient Absorption ◽  
Ultrafast Transient Absorption Spectroscopy

Ultrafast transient absorption spectroscopy and density functional theory calculations are utilized to get a better understanding of photophysical and photochemical reaction mechanisms of AB-Me, AB-Pr, AB-Br and AB-Cl.

Decoupling the artificial special pair to slow down the rate of singlet energy transfer

2012 ◽  
Vol 16 (05n06) ◽  
pp. 685-694 ◽  
Author(s):  
Pierre D. Harvey ◽  
Adam Langlois ◽  
Mikhail Filatov ◽  
Daniel Fortin ◽  
Kei Ohkubo ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Absorption Spectroscopy ◽  
Density Functional ◽  
Transient Absorption ◽  
Geometry Optimization ◽  
Transient Absorption Spectroscopy ◽  
Free Base ◽  
Functional Theory ◽  
Time Resolved ◽  
Slow Rise

Trimer 2, composed of a cofacial heterobismacrocycle, octamethyl-porphyrin zinc(II) and bisarylporphyrin zinc(II) held by an anthracenyl spacer, and a flanking acceptor, bisarylporphyrin free-base ( Ar = -3,5-(t Bu )2 C 6 H 3), has been studied by means of absorption spectroscopy, "steady state and time-resolved fluorescence" and fs transient absorption spectroscopy, and density functional theory (DFT) in order to assess the effect of decoupling the chromophores' low energy MOs on the rate of the singlet, S1, energy transfer, k ET , compared to a recently reported work on a heavily coupled trimeric system, Trimer 1, [biphenylenebis(n-nonyl)porphyrin zinc(II)]-bisarylporphyrin free-base ( Ar = -3,5-(t Bu )2 C 6 H 3). The position of the 0–0 peaks of the absorption and fluorescence spectra of Trimer 2 indicates that these porphyrin units are respectively energy donor 1, donor 2, and acceptor. The DFT computations confirm that the MOs of the cofacial donor 1-donor 2 dyad are decoupled, but significant MO coupling between donor 2 and acceptor 1 is still present despite the strong dihedral angle between their respective average planes (77.5°: geometry optimization by DFT). The fs transient absorption spectra exhibit a clear S1–Sn fingerprint of the bisarylporphyrin zinc(II) chromophore and the kinetic trace exhibits a slow rise time of 87 ps, due to a S1 donor 1 → donor 2 ET. The transient species donor 2 and acceptor decay respectively in the short (~1.5) ns and 6 ns time scale.

UV Two-Dimensional Transient Absorption Spectroscopy

2012 ◽  
Author(s):  
Gerald Auböck ◽  
Cristina Consani ◽  
Frank van Mourik ◽  
Majed Chergui
Keyword(s):  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Two Dimensional

scholarly journals In situ characterization of few-cycle laser pulses in transient absorption spectroscopy

2015 ◽  
Vol 40 (15) ◽  
pp. 3464 ◽  
Author(s):  
Alexander Blättermann ◽  
Christian Ott ◽  
Andreas Kaldun ◽  
Thomas Ding ◽  
Veit Stooß ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Laser Pulses ◽  
Transient Absorption Spectroscopy ◽  
In Situ Characterization
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