Hot Carrier Trapping and It's Influence to the Carrier Diffusion in CsPbBr₃ Perovskite Film Revealed by Transient Absorption Microscopy

Advanced Science, Journal Year: 2024, Volume and Issue: 11(28)

Published: May 10, 2024

Abstract The defects in perovskite film can cause charge carrier trapping which shortens lifetime and diffusion length. So passivation has become promising for the studies. However, how disturb transport passivating affects CsPbBr 3 are still unclear. Here dynamics processes of LiBr passivated films investigated by using transient absorption spectroscopy microscopy. It's found that there is a fast hot process with above bandgap excitation, would decrease population cold carriers diffusible, then lower constant. proved passivate defect probability carriers, thus improve rate. finding demonstrates influence to film.

Language: Английский

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Real-space imaging of photo-generated surface carrier transport in 2D perovskites

Light Science & Applications, Journal Year: 2025, Volume and Issue: 14(1)

Published: March 18, 2025

Abstract In layered two-dimensional (2D) perovskites, the inorganic perovskite layers sandwiched between cation spacers create quantum well (QW) structures, showing large exciton binding energies that hinder efficient dissociation of excitons into free carriers. This leads to poor carrier transport properties and low-performance light-conversion-based devices, direct understanding underlying physics, particularly concerning surface states, remains extremely difficult, if not impossible, due challenges in real-time accessibility. Here, we utilized four-dimensional scanning ultrafast electron microscopy (4D-SUEM), a highly sensitive technique for mapping diffusion diverges from those bulk substantially affects material properties. We directly visualize photo-generated over both spatial temporal dimensions on top 2D perovskites with varying layer thicknesses ( n = 1, 2, 3). The results reveal photo-induced rates ~30 cm 2 ·s -1 ~180 ~470 3, which are 20 times larger than bulk. is because charge transmission channels have much wider distributions compared bulk, as supported by Density Functional Theory (DFT) calculations. Finally, our findings represent demonstration correlate discrepancies behaviors, their relationship energy, number providing valuable insights enhancing performance perovskite-based optoelectronic devices through interface engineering.

Language: Английский

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Ultrafast Carrier Dynamics in CH₃NH₃PbBr₃ Perovskite Single-Crystal Thin Films

The Journal of Physical Chemistry C, Journal Year: 2025, Volume and Issue: 129(9), P. 4481 - 4489

Published: Feb. 24, 2025

Single-crystal (SC) perovskites have emerged as promising contenders for perovskite solar cells (PSCs) and the next generation of optoelectronic devices. Compared to polycrystalline (PLC) perovskites, SC reduced trap densities, enhanced carrier mobility, extended lifetime. However, a comprehensive understanding dynamics in SCs is still lacking, primarily due their bulk dimensions, which are not suitable ultrafast spectroscopic studies. Here, we prepared spectroscopically thin films investigating photophysical properties. It found that excitation above band gap results quasi-thermalization distributions within 100 fs, with an initial temperature film three times higher than PLC film. Our indicate contribution inelastic carrier–carrier scattering significantly lower During cooling, short-lived sub-band transient absorption signal arises only film, can be explained by interplay renormalization hot-carrier distributions. it absent until density surpasses amplified spontaneous emission threshold. Furthermore, cooling hot carriers accelerated stronger interaction between photocarrier lattice.

Language: Английский

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Stabilized Yolk–Shell Perovskite CsPbBr₃/Rb₄PbBr₆ Nanocrystals for Green-Emitting Light-Emitting Diodes

ACS Applied Nano Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 27, 2025

Language: Английский

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Thermally Stable Cellulose-Based Triboelectric Nanogenerators with Ultrahigh Charge Density Enabled by Deep Traps and Multiple Noncovalent Interactions

Nano Letters, Journal Year: 2025, Volume and Issue: unknown

Published: March 29, 2025

Stable high-output for triboelectric nanogenerators (TENGs) in extreme environments is challenged by high charge dissipation rates and friction layer degradation at temperatures. This study introduces a material design that ensures stable temperatures through synergistic approach of multilayer noncovalent bonding increased surface deep trap density. By grafting sulfonic acid groups onto cellulose incorporating self-assembled molecules with large energy gaps, we significantly enhance the dielectric's storage capacity reduce 82%. The modified exhibits notable increase density improved mechanical properties enhanced high-enthalpy states from interactions. As result, TENGs achieve an ultrahigh 152 μC/m2 250 °C. strategy presents simple method constructing stabilized electrical output high-temperature settings, facilitating their use as self-powered sensors conditions.

Language: Английский

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Tuning Hot-Carrier Temperature in CsPbBr₃ Perovskite Nanoplatelets through Metal Halide Passivation

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 3832 - 3839

Published: April 8, 2025

High carrier temperature and slow cooling make perovskite nanostructures potential candidates for hot-carrier solar cells. Here, using time-resolved photoluminescence spectroscopy, dynamics is reported in strongly confined three-monolayer quasi-2D CsPbBr3 nanoplatelets characterized by sharp excitonic peaks the absorption spectrum narrow emission blue region. Treatment with a PbBr2-ligand solution resulted remarkable seven-fold increase intensity, attributed to effective passivation of surface defects due lead(II) bromide vacancies. Further investigations spectroscopy revealed consistent times ∼300 fs both pristine treated nanoplatelets, indicating similar fundamental processes. Notably, exhibited higher (∼700 K), linked increased radiative density after defect passivation. This work demonstrates that treatment metal halides substantially improves optoelectronic properties. temperatures can be significantly while preserving time.

Language: Английский

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Observation of the Molecular Passivation Effect upon Ultrafast Fermi Population Process in Perovskite Films

The Journal of Physical Chemistry C, Journal Year: 2025, Volume and Issue: unknown

Published: April 8, 2025

Language: Английский

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Sensitized Near-Infrared Emission of SiGe Nanocrystals via Heterostructuring with Quasi Two-Dimensional Perovskite

ACS Applied Materials & Interfaces, Journal Year: 2025, Volume and Issue: unknown

Published: April 23, 2025

The near-infrared (NIR) emission of silicon-germanium alloy nanocrystals (SiGe NCs) was sensitized by heterostructuring with a quasi two-dimensional (Q-2D) perovskite (CsPbBr3 blended butylammonium bromide (BABr)). Colloidal SiGe NCs were synthesized using nonthermal plasma method chloride precursors. As-synthesized showed no detectable photoluminescence (PL). Embedding the within matrix via spin coating led to heterostructure exhibiting dual emissions: green at 520 nm from and NIR 1035 NCs. Time-integrated resolved PL measurements transient absorption spectroscopy revealed energy transfer NCs, which quenched for perovskite. These results demonstrate that Ge alloying can effectively tune bandgap Si highlight feasibility perovskites photoluminescent enhance or activate their PL. This approach broadens potential applications in region.

Language: Английский

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Charge Transfer and Retention in 2D Passivated Perovskite–C₆₀ Systems

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(50), P. 12334 - 12340

Published: Dec. 7, 2024

2D perovskites and organic ligands are often implemented as passivating interlayers in perovskite solar cells. Herein, five such passivates evaluated by using time-resolved spectroscopy to study the carrier dynamics at perovskite-C60 interface. The impact of passivation on factors charge transfer rate, retention acceptor layers, surface recombination, uniformity mapped onto cell performance. was found take place tens nanoseconds, without any passivate lasted a few hundred nanoseconds. that produced best cells, ethylenediammonium iodide, extended time up one microsecond, which significantly increased open-circuit voltage. It also had hence least variance power conversion efficiency. Curiously, it did not merely adjust energy states enhance but extracted charges itself C60, resulting higher short-circuit current.

Language: Английский

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Long-range hot carrier transport in lead-free cesium tin halide perovskite microplates

Applied Physics Letters, Journal Year: 2024, Volume and Issue: 125(25)

Published: Dec. 16, 2024

The carrier dynamics of lead-free cesium tin halide perovskites are crucial for evaluating their potential as substitutes lead-based perovskites. Herein, we investigate the ultrafast transport hot carriers in CsSnBr3 microplates synthesized via chemical vapor deposition. We observe a significantly prolonged cooling process lasting ∼50 ps, due to hot-phonon bottleneck effect and formation large polarons. By employing transient absorption microscopy, detect time-dependent diffusion coefficient initially reaching up 257.8 cm2·s−1, leading long average travel distance ∼600 nm. Subsequently, it reveals remarkable equilibrium ranging from 12.7 16.5 cm2·s−1. These findings establish fundamental basis designing advancing perovskite-based optoelectronic applications involving carriers.

Language: Английский

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