Quantum Dynamics of Charge Carriers in Fullerenes Encapsulated by Covalent Organic Polyhedra: Choice of Fullerene Matters

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 28, 2025

Charge separation is at the heart of solar energy applications, and efficient materials require fast photoinduced electron transfer (ET) slow charge recombination (CR). Using time-dependent self-consistent density functional tight-binding theory combined with nonadiabatic (NA) molecular dynamics, we report a detailed analysis ET CR in hybrids composed photoactive covalent organic polyhedra (COP) encapsulated fullerenes. The occurs on subpicosecond time scale accelerates increasing fullerene diameter, C60 to C70 C84. As size increases, π-electron system available for interaction COP grows, fullerene-COP decreases, number states accept photoexcited accelerating ET. In comparison, nanosecond correlates length shortest axis because relevant state polarized that direction. largest least symmetrical C84 exhibits fastest slowest CR, making COP@C84 most promising hybrid. Both high-frequency bond stretching bending vibrations low-frequency breathing modes are involved processes, more present due its lower symmetry. 10–20 fs vibrationally induced coherence loss electronic subsystem contributes long lifetimes charge-separated states. comprehensive investigation structure–property relationship carrier dynamics COP@fullerene provides atomistic understanding interfacial processes generates guidelines rational design high-performance related applications.

Language: Английский

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Hot carrier relaxation dynamics of an aza-covalent organic framework during photoexcitation: An insight from ab initio quantum dynamics

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(16)

Published: April 22, 2024

In order to develop an efficient metal-free solar energy harvester, we herein performed the electronic structure calculation, followed by hot carrier relaxation dynamics of two dimensional (2D) aza-covalent organic framework time domain density functional calculations in conjunction with non-adiabatic molecular (NAMD) simulation. The calculation shows that (COF) is a direct bandgap semiconductor acute charge separation and effective optical absorption UV-visible region. Our study simulation predicts sufficiently prolonged electron-hole recombination process (6.8 nanoseconds) comparatively faster electron (22.48 ps) hole (0.51 this two-dimensional aza-COF. According our theoretical analysis, strong electron-phonon coupling responsible for rapid relaxation, whereas slowed down relatively weak coupling, lower quick decoherence time. We do hope results NAMD on exciton will be helpful designing photovoltaic devices based

Language: Английский

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Impact of large A-site cations on electron–vibrational interactions in 2D halide perovskites: Ab initio quantum dynamics

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(11)

Published: March 20, 2024

Using ab initio nonadiabatic molecular dynamics, we study the effect of large A-site cations on nonradiative electron-hole recombination in two-dimensional Ruddlesden-Popper perovskites HA2APb2I7, HA = n-hexylammonium, A methylammonium (MA), or guanidinium (GA). The steric hindrance created by GA distorts and stiffens inorganic Pb-I lattice, reduces thermal structural fluctuations, maintains delocalization electrons holes at ambient elevated temperatures. delocalized charges interact more strongly system than MA system, charge is accelerated. In contrast, replacement only some with enhances disorder increases lifetime, as seen three-dimensional perovskites. This highlights key influence fluctuations properties carriers metal halide perovskites, providing guidance for tuning materials' optoelectronic performance.

Language: Английский

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Prolonged Exciton Lifetime Is Achieved in Porphyrin Nanoring by Template Engineering: A Nonadiabatic Tight Binding Approach

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(17), P. 4737 - 4744

Published: April 25, 2024

Porphyrin nanoring has been attracting immense attention due to its light harvesting capacity and potential applications in optical, catalysis, sensor, electronic devices. We demonstrate by nonadiabatic quantum dynamics simulations that the photovoltaic efficiency can be enhanced template engineering. Altering hexadentate (T6) with two tridentate templates (2T3) within porphyrin ring (P6) cavity accelerated electron transfer twice suppressed electron–hole recombination nearly three times. The atomistic tight-binding simulation rationalized different localizations of charge band edge states, changes coupling, alteration coherence, involvement diverse electron–phonon vibrational modes. Further 2T3 more strongly hold P6 than T6, reducing structural fluctuation. As a result, coupling becomes weaker suppresses carrier recombination. Current presents engineering strategy enhance exciton lifetime along ultrafast separation, crucial factors for applications.

Language: Английский

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Relaxation of Photoexcited Electron–Hole Pairs at Si(111) Surfaces with Adsorbed Ag Monolayered Clusters of Increasing Size

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 2905 - 2913

Published: March 11, 2025

The efficiency of silicon solar cells is affected by the light absorption and recombination losses photoexcited charge carries. One possible way to improve through deposition transition metal nanoparticles on Si surfaces. Here, we first carry out density functional theory (DFT) calculations obtain electronic structures for Agn (n = 1–7) monolayered clusters adsorbed Si(111)/H Results are presented in form states, band gaps, absorption, which allow investigation interaction Ag with Si. Different behaviors can be expected depending size deposited clusters. Overall, leads smaller red-shifts, large increases compared pristine slab. We then study relaxation dynamics electron–hole pairs slabs based nonadiabatic couplings using reduced matrix approach within Redfield formalism. Nonradiative rates noticeably different various transitions. observes higher surfaces adsorbates than surface due transfer events involving orbitals. also compute emission spectra from excited-state dynamics. gap dark indirect nature its gap. addition larger breaks symmetry slabs, enabling These thus exhibit bright emission. introduction advantageous applications photovoltaics photocatalysis.

Language: Английский

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Electron–Hole Recombination Is Suppressed by Breaking the Ring Planarity in Porphyrin Nanorings: Density Functional Atomistic Simulation

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

Published: March 27, 2025

Porphyrin nanorings get enormous attention as potential photovoltaic materials due to their unique and tunable optoelectronic properties. Distribution of charge in porphyrin can alter the performance. We investigate photodynamics two nanorings, i.e., fused meso observe role delocalization on carrier relaxation dynamics. Employing nonadiabatic molecular dynamics within framework density functional tight binding theory, we demonstrate that nanoring exhibits six times longer exciton lifetime compared nanoring. Charges are more localized at band edge states reduce orbital overlap between electron hole wave functions. As a result, localization weakens coupling, resulting delayed electron–hole (e−h) recombination. Participation low-frequency electron-vibrational modes rapid decoherence energy gap further extends lifetime. Additional β conjunctions dimer facilitate throughout because fusions hold circular planarity Quick creates strong ground excited states, quick Further, simulated transition rate support our results. e−h recombination is dependent Our simulations give light effect by tuning geometry provide valuable guidance design high-performance organic conjugated system-based appliances.

Language: Английский

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Hard–Soft Acid–Base Theory Explains Photoexcited Carrier Dynamics in Porphyrin/CNT Nanohybrids: Time-Domain Atomistic Analysis

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: June 5, 2025

We employ the fundamental chemical concepts of hard-soft acid-base to formulate general principles governing excited-state dynamics in zinc porphyrin (ZnP)/carbon nanotube (CNT) hybrids for energy photoconversion. Atomistic quantum simulations demonstrate that electron-withdrawing and donating substituents at ZnP β-pyrrolic position strongly influence dynamics. photoexcitation produces subpicosecond electron transfer (ET) from CNT, agreement with experiment. Substitutions CN by H tBu accelerate ET. The trend is directly related concept because soft-soft interaction between tBu-ZnP acid mild CNT base enhances donor-acceptor coupling. Longer coherence more active vibrational modes facilitate ET tBu-ZnP/CNT. Electron-hole recombination CN-ZnP/CNT occurs on a hundred picosecond time scale, nicely corroborated exciton lifetime extended beyond nanosecond substitutions. tBu-ZnP/CNT increases splitting highest occupied orbitals two subsystems, reduces their mixing, decreases nonadiabatic coupling ground excited states. Rapid decoherence involvement low-frequency vibrations favor longer lifetimes. Our investigation reveals larger pKa gives rapid slow provides detailed mechanistic information, essential future optoelectronic applications.

Language: Английский

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On Analytical Modeling of Hopping Transport of Charge Carriers and Excitations in Materials with Correlated Disorder

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(9), P. 2601 - 2605

Published: Feb. 28, 2024

Spatial-energy correlations strongly influence charge and exciton transport in weakly ordered media such as organic semiconductors nanoparticle assemblies. Focusing on cases with shorter-range interparticle interactions, we develop a unified analytic approach that allows us to calculate the temperature field dependence of carrier mobility quadrupole glasses diffusion coefficient excitons quantum dot solids. We obtain expressions for energy distribution hopping centers, characteristic escape time charge/exciton from well stemming around deep states, size well. The derived formulas are tested Monte Carlo simulation results, showing good agreement providing simple analysis broad range partially media.

Language: Английский

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Controlling the Charge Carrier Dynamics of o-B₂N₂ Monolayer through Pnictogen Family Atoms Doping

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(37), P. 9388 - 9396

Published: Sept. 6, 2024

In the quest for an efficient solar energy harvester, one should focus on materials that have a large carrier lifetime. Using time-domain density functional theory combined with nonadiabatic molecular dynamics simulations, we herein established single-atom doping from pnictogen family can effectively alter electron-hole recombination time in o-B

Language: Английский

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Positively Photo‐Responsive Adsorption Over Binary Copper Porphyrin Framework and Graphene Film Sorbents

Small, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 30, 2024

Abstract Photo‐responsive adsorption has emerged as a vibrant area because it provides promising route to reduce the energy consumption of traditional separation. However, current methodology fabricate photo‐responsive sorbents is still subject photo‐deforming molecular units. In this study, new initiative photo‐dissociated electron‐hole pairs proposed generate amazing activity, and prove its feasibility. Employing CuPP [PP = 5,10,15,20‐tetrakis(4‐carboxyphenyl)porphyrin] framework nanosheets compounded with graphene, binary film (BF) are successfully fabricated. The paradigmatic BF nanostructure brings about efficiently photo‐excited durable enough lifetime meet needs microscopic equilibrium, which ultimately alters electron density distribution surface, thus markedly modulates activity. Therefore, an photo‐enhanced capability for index gas CO can be gotten. Once exposed visible‐light at 420 nm, capacity (0 °C, 1 bar) risen from 0.23 mmol g −1 in darkness 1.66 , changed by + 622%. This essentially different majority based on units, only decreased photo‐induction, maximum rate change reported just −54%.

Language: Английский

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