Hole Trapping in Lead Halide Perovskite Nanocrystal–Viologen Hybrids and Its Impact on Back Electron Transfer

ACS Nano, Год журнала: 2025, Номер unknown

Опубликована: Март 4, 2025

Control of forward and back electron transfer processes in semiconductor nanocrystals is important to maximize charge separation for photocatalytic reduction/oxidation processes. By employing methyl viologen as the acceptor, we have succeeded mapping from excited CsPbI3 well hole trapping process. The an ultrafast process (ket = 2 × 1010 s-1) results formation extended electrons are trapped at surface-bound sites holes iodide sites. I2─• formation, which confirmed through transient absorption 750 nm, provides a convenient way probe its participation series mixed halide compositions, were able tune bandgap valence band energy perovskite donor. rate constant (kbet 1.3-2.6 107 nearly three orders magnitude smaller than that transfer, thus extending lifetime charge-separated state. weak dependence on suggests (I or Br) involved ability extend pair can offer new strategies improve redox properties semiconductor-based systems.

Язык: Английский

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Directional Electron Transfer across In₂S₃/ZnS-Embedded Photocatalytic Membranes

ACS Applied Energy Materials, Год журнала: 2024, Номер 7(2), С. 681 - 688

Опубликована: Янв. 5, 2024

Photocatalytic membranes prepared with semiconductor nanoparticles embedded in a polymer film offer convenient approach to direct the electron and hole flow separate reduction oxidation products. We have now In2S3 ZnS Nafion membrane induce photocatalytic reactions using visible light. In addition, we incorporated viologen redox relay within facilitate transfer thionine (TH) dissolved water. By inserting H-cell, can products track steady-state photolysis transient absorption spectroscopy. The enhanced charge separation heterostructure at 50:50 loading allowed us maximize electron-transfer yield. Directing such vectorial will be useful suppressing undesired side (e.g., re-oxidation of reduced product) facilitating product separation.

Язык: Английский

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How Effective Are Sub-Bandgap States in AgInS₂ Quantum Dots for Electron Transfer?

Chemistry of Materials, Год журнала: 2024, Номер 36(9), С. 4591 - 4599

Опубликована: Апрель 22, 2024

Ternary I–III–VI2 semiconductors, such as CuInS2 and AgInS2 (compliant with RoHS, restriction of hazardous substances), are useful light-harvesting materials. However, the presence sub-bandgap states (donor–acceptor pair or DAP) introduces complexity during their activation through photoexcitation. When photoirradiated, photogenerated charge carriers in quantum dots undergo rapid relaxation to populate intrinsic DAP while competing carrier recombination. Interestingly, these defect-related can be activated excitation and, thus, extend absorption range near-infrared region. We have now employed time-resolved emission techniques glean mechanistic insights into photophysical properties intragap (QDs) participation interfacial electron transfer. QDs excited above bandgap (400 nm), we observe a prompt formation (<1 ps) bleach at wavelengths closer bandgap, indicating charge-separated pair. This transient shifts lower energies time (∼5 ps), population via electrons holes from conduction valence bands, respectively. These which also populated direct using low energy (λ < Eg) exhibit contrast excitation. The long-lived (∼1 μs) participate transfer process. elucidated dynamics midgap by employing ethyl viologen (EV2+) probe molecule. role surface-anchored an shuttle was further exploited free-floating benzoquinone (BQ) secondary acceptor. response promote paves way photoresponse ternary semiconductor-based photocatalytic systems.

Язык: Английский

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Interplay between photoinduced charge and energy transfer in manganese doped perovskite quantum dots

The Journal of Chemical Physics, Год журнала: 2024, Номер 160(24)

Опубликована: Июнь 24, 2024

A comprehensive study on the photo-excited relaxation dynamics in semiconducting perovskite quantum dots (PQDs) is pivotal realizing their extensive potential for optoelectronics applications. Among different competing photoinduced kinetics, energy transfer and charge (CT) PQDs need special attention, as they often influence device efficacy, particularly with donor–acceptor hybrid architecture. In this work, we explore a detailed investigation into CT mixed halide undoped CsPb(Br/Cl)3 Mn2+ doped quinone molecule, p-benzoquinone (BQ). The level alignment of BQ allows an efficient CT, whereas doping reduces efficiency, experiencing competition between from host to dopant BQ. conductive atomic force microscopy measurements unveil direct correlation spectroscopic studies by showing significant improvement conductance presence BQ, while inappreciable change observed PQDs. much-reduced transition voltage barrier height further validate faster PQD than one. Furthermore, enhance stability, better air thermal stability compared counterparts. These results reveal that strategy can regulate these increase which will be beneficial development desired optoelectronic devices long-term stability.

Язык: Английский

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Stepwise Surface Ligand Engineering on Gold Nanoclusters: Controlled Photochemistry, Solvation Dynamics and Photosensitization

ACS Applied Optical Materials, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

The effect of stepwise surface modification 6-azo-thiothyamine (ATT) protected AuNCs (ATT-AuNCs), initially with l-Arginine (Arg@ATT-AuNCs) and further cationic surfactants, such as CTAB (CTAB-Arg@ATT-AuNCs) DTAB (DTAB-Arg@ATT-AuNCs), has been reported here. Stepwise ligand engineering (SSLE) significantly slows down the nonradiative transition rate in following order: ATT-AuNCs < Arg@ATT-AuNCs DTAB-Arg@ATT-AuNCs CTAB-Arg@ATT-AuNCs, which increases average radiative lifetime same order. This process also photoluminescence quantum yield (PLQY) trend (2% 41% 58% 72%). There is a simultaneous on solvation dynamics respective where time order CTAB-Arg@ATT-AuNCs. Methyl viologen-derived photosensitization subsequent photoinduced electron transfer (PET) efficiency tested. These are singlet oxygen generators modulate exactly to that PLQY. This, our knowledge, first comprehensive report SSLE control photochemistry, generating propensity.

Язык: Английский

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Surface chemistry-engineered perovskite quantum dot photovoltaics

Chemical Society Reviews, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

This review summarizes the progress and provides perspectives on perovskite quantum dot photovoltaics, with a focus surface chemistry engineering, paving new direction for large-area low-cost PV technology to address major energy challenges.

Язык: Английский

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Surface Considerations in Colloidal Semiconductor Nanocrystal Photocatalysis: A Mini Review

Energy & Fuels, Год журнала: 2025, Номер unknown

Опубликована: Апрель 9, 2025

Язык: Английский

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Enhancing Photocatalytic Attributes of Perovskite Nanocrystals in Aqueous Media via Ligand Engineering

ACS Applied Materials & Interfaces, Год журнала: 2023, Номер 16(1), С. 623 - 632

Опубликована: Дек. 19, 2023

The remarkable catalytic potential of perovskite nanocrystals (NCs) remains underutilized due to their limited stability in polar media, resulting from the vulnerability structure disruption by solvents. In this study, we address challenge employing bolaamphiphilic NKE-12 ligand, which features multiple denticities effectively shield surface CsPbBr

Язык: Английский

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Modulation of carrier conduction in CsPbBr3 perovskite quantum dots with band-aligned electron and hole acceptors

The Journal of Chemical Physics, Год журнала: 2023, Номер 159(18)

Опубликована: Ноя. 9, 2023

The lead halide perovskites have emerged as promising materials with intriguing photo-physical properties and immense potential for photovoltaic applications. A comprehensive study on the kinetics of charge carrier (electron/hole) generation transfer across interface is key to realizing their future scope efficient device engineering. Herein, we investigate interfacial (CT) dynamics in cesium (CsPbBr3) perovskite quantum dots (PQDs) energetically favorable electron acceptors, anthraquinone (AQ) p-benzoquinone (BQ), hole acceptors such pyrene 4-(dimethylamino)pyridine (DMAP). With various steady-state time-resolved spectroscopic microscopic measurements, a faster rate estimated CsPbBr3 PQDs BQ compared that AQ, while superior DMAP divulged pyrene. In concurrence conducting atomic force studies electrode-PQD-electrode junction reveals an increment conductance PQD presence both acceptors. variation density states calculation offers strong support validation CT efficiency. above findings suggest careful selection simple yet molecular arrangements can facilitate rapid transfer, which be designed auxiliary layers smooth help engineering cost-effective devices.

Язык: Английский

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Efficient Photocatalytic Hydrogen Production Using In‐Situ Polymerized Gold Nanocluster Assemblies

Small, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 19, 2024

Abstract Gold nanoparticles (NPs) are widely recognized as co‐catalysts in semiconductor photocatalysis for enhancing hydrogen production efficiency, but they often overlooked primary catalysts due to the rapid recombination of excited‐state electrons. This study presents an innovative gold‐based photocatalyst design utilizing situ dopamine polymerization‐guided assembly approach efficient H 2 generation via water splitting. By employing gold superclusters (AuSCs; ≈100 nm) instead ultra‐small nanoclusters (AuNCs; ≈2 before polymerization, unique nanodisk‐like 3D superstructures consisting agglomerated 2D polydopamine (PDA) nanosheets with a high percentage uniformly embedded AuNCs created that exhibit enhanced metallic character post‐polymerization. The thin PDA layer between adjacent functions electron transport medium, directing electrons toward surface and minimizing recombination. Notably, AuSCs@PDA structure shows largest potential difference (26.0 mV) compared AuSCs (≈18.4 NPs (≈14.6 mV), indicating higher population accumulated photo‐generated carriers. As result, achieves photocurrent density, improved photostability, lower charge transfer resistance than NPs, AuSCs, or AuNCs@PDA, highest evolution rate 3.20 mmol g −1 h . work highlights promising polymerization strategy photocatalytic metal nanoclusters.

Язык: Английский

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