Exciton–polaron interactions in metal halide perovskite nanocrystals revealed via two-dimensional electronic spectroscopy

The Journal of Chemical Physics, Journal Year: 2023, Volume and Issue: 159(18)

Published: Nov. 14, 2023

Metal halide perovskite nanocrystals have been under intense investigation for their promise in optoelectronic devices due to remarkable physics, such as liquid/solid duality. This duality may give rise defect tolerance and other useful properties. means that the electronic states are fluctuating time, on a distribution of timescales from femtoseconds picoseconds. Hence, these lattice induced energy fluctuations connected polaron formation also exciton dynamics. We observe correlations dynamics metal CsPbI3 CsPbBr3 using two-dimensional (2DE) spectroscopy, with its unique ability resolve heterogeneously broadened systems. The 2DE spectra immediately reveal previously unobserved excitonic splitting 15 nm NCs coarse structure. 2D lineshape glassy response 300 fs timescale formation. lighter Br system shows larger amplitude faster dynamic line broadening. signals enable 1D transient absorption analysis cooling Exciton within this doublet is shown take place slower than continuum. dissipation rates same I systems incoherent but very different coherent formation, revealing both coupled many-body excitation.

Language: Английский

---

Full visible range two-dimensional electronic spectroscopy with high time resolution

Optics Express, Journal Year: 2023, Volume and Issue: 32(1), P. 835 - 835

Published: Dec. 15, 2023

Two-dimensional electronic spectroscopy (2DES) is a powerful method to study coherent and incoherent interactions dynamics in complex quantum systems by correlating excitation detection energies nonlinear experiment. Such can be probed with time resolution limited only the duration of employed laser pulses spectral range defined pulse spectrum. In blue (<500 nm), generation sufficiently broadband ultrashort durations 10 fs or less has been challenging so far. Here, we present 2DES setup based on hollow-core fiber supercontinuum covering full visible (400-700 nm). Pulse compression via custom-made chirped mirrors yields <10 fs. The broad coverage, particular extension spectra into range, unlocks new possibilities for investigations blue-light absorbing multichromophoric compounds, as demonstrated measurement chlorophyll a.

Language: Английский

---

Two-dimensional electronic spectroscopy from first principles

Applied Physics Reviews, Journal Year: 2024, Volume and Issue: 11(1)

Published: Jan. 24, 2024

The recent development of multidimensional ultrafast spectroscopy techniques calls for the introduction computational schemes that allow simulation such experiments and interpretation corresponding results from a microscopic point view. In this work, we present general efficient first-principles scheme to compute two-dimensional electronic maps based on real-time time-dependent density-functional theory. interface approach with Ehrenfest molecular dynamics enables inclusion vibronic effects in calculations classical treatment nuclei. complexity simulations is reduced by application numerical advances as branching techniques, undersampling, novel phase cycling scheme, applicable systems inversion symmetry. We demonstrate effectiveness method applying it prototypical molecules benzene, pyridine, pyrene. discuss role approximations inevitably enter adopted theoretical framework set stage further extensions proposed more realistic systems.

Language: Английский

---

Nonadiabatic Charge Transfer within Photoexcited Nickel Porphyrins

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(13), P. 3627 - 3638

Published: March 26, 2024

Metalloporphyrins with open d-shell ions can drive biochemical energy cycles. However, their utilization in photoconversion is hampered by rapid deactivation. Mapping the relaxation pathways essential for elaborating strategies that favorably alter charge dynamics through chemical design and photoexcitation conditions. Here, we combine transient optical absorption spectroscopy X-ray emission femtosecond resolution to probe directly coupled electronic spin within a photoexcited nickel porphyrin solution. Measurements calculations reveal state charge-transfer character mediates formation of thermalized excited state, thereby advancing description photocycle this important representative molecule. More generally, establishing intramolecular steps play role photoinduced metalloporphyrins sets conceptual ground development as building blocks capable boosting nonadiabatic functional architectures "hot" transfer down attosecond time scale.

Language: Английский

---

On-the-Fly Simulation of Two-Dimensional Fluorescence–Excitation Spectra

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(34), P. 8728 - 8735

Published: Aug. 20, 2024

Two-dimensional (2D) fluorescence-excitation (2D-FLEX) spectroscopy is a recently proposed nonlinear femtosecond technique for the detection of photoinduced dynamics. The method records time-resolved fluorescence signal in its excitation- and detection-frequency dependence hence combines exclusive excited state dynamics (fluorescence) with signals resolved both excitation emission frequencies (2D electronic spectroscopy). In this work, we develop an on-the-fly protocol simulation 2D-FLEX spectra molecular systems, which based on interfacing classical doorway-window representation spectroscopic responses trajectory surface hopping simulations. Applying methodology to gas-phase pyrazine, show that can deliver detailed information otherwise obtainable via attosecond spectroscopy.

Language: Английский

---