Nonadiabatic Derivative Couplings through Multiple Franck–Condon Modes Dictate the Energy Gap Law for Near and Short-Wave Infrared Dye Molecules

The Journal of Physical Chemistry Letters, Год журнала: 2024, Номер 15(7), С. 1802 - 1810

Опубликована: Фев. 8, 2024

Near infrared (NIR, 700–1000 nm) and short-wave (SWIR, 1000–2000 dye molecules exhibit significant nonradiative decay rates from the first singlet excited state to ground state. While these trends can be empirically explained by a simple energy gap law, detailed mechanisms of nearly universal behavior have remained unsettled for many cases. Theoretical experimental results two representative NIR/SWIR reported here clarify key mechanism observed law behavior. It is shown that derivative nonadiabatic coupling terms serve as major pathways processes NIR SWIR vibrational modes other than highest frequency also make contributions rate. This assessment corroborated further theoretical comparison with possible alternative intersystem crossing triplet states data deuterated molecules.

Язык: Английский

---

Self-passivation of Halide Interstitial Defects by Organic Cations in Hybrid Lead-Halide Perovskites: Ab Initio Quantum Dynamics

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(42), С. 29255 - 29265

Опубликована: Окт. 11, 2024

Halide interstitial defects severely hinder the optoelectronic performance of metal halide perovskites, making research on their passivation crucial. We demonstrate, using ab initio nonadiabatic molecular dynamics simulations, that hydrogen vacancies (H

Язык: Английский

---

Detrimental Defect Cooperativity at TiO₂/CH₃NH₃PbI₃ Interface: Decreased Stability, Enhanced Ion Diffusion, and Reduced Charge Lifetime and Transport

ACS Energy Letters, Год журнала: 2024, Номер unknown, С. 5888 - 5897

Опубликована: Ноя. 18, 2024

Interfaces are essential for solar cell performance since they govern charge separation and transport. Using quantum dynamics simulation, we demonstrate that at interfaces, common defects benign on their own, iodine vacancy in CH3NH3PbI3 (VI) oxygen TiO2 (VO), responsible synergistically poor stability losses. VO promotes VI diffusion accelerates migration. A midgap trap state appears, inhibiting transport accelerating recombination by an order of magnitude. Strong structural distortions strengthen electron-vibrational interactions activate high-frequency phonons. Because the widely reported high defect-tolerance lead-halide perovskites, synergistic detrimental influence perovskite with other materials is often overlooked. The interfacial defect pairing could be a major reason losses cells. results suggest either high-quality or extraction layer may sufficient to achieve performance.

Язык: Английский

---

Extending the Time Scales of Nonadiabatic Molecular Dynamics via Machine Learning in the Time Domain

The Journal of Physical Chemistry Letters, Год журнала: 2021, Номер 12(50), С. 12119 - 12128

Опубликована: Дек. 16, 2021

A novel methodology for direct modeling of long-time scale nonadiabatic dynamics in extended nanoscale and solid-state systems is developed. The presented approach enables forecasting the vibronic Hamiltonians as a function time via machine-learning models trained directly domain. use periodic aperiodic functions that transform into effective input modes artificial neural network demonstrated to be essential such an work both abstract atomistic models. best strategies possible limitations pertaining new are explored discussed. An exemplary simulation unprecedentedly long 20 picosecond trajectories conducted divacancy-containing monolayer black phosphorus system, importance conducting simulations demonstrated. New insights excited states photophysics this system presented, including role decoherence model definition.

Язык: Английский

---

Anion Doping Delays Nonradiative Electron–Hole Recombination in Cs-Based All-Inorganic Perovskites: Time Domain ab Initio Analysis

The Journal of Physical Chemistry Letters, Год журнала: 2022, Номер 13(49), С. 11375 - 11382

Опубликована: Дек. 1, 2022

Using time-domain density functional theory combined with nonadiabatic (NA) molecular dynamics, we demonstrate that composition engineering of the X-site anions has a strong influence on nonradiative electron–hole recombination and thermodynamic stability cesium-based all-inorganic perovskites. Partial substitution iodine(I) bromine (Br) acetate (Ac) reduces NA electron–vibrational coupling by minimizing overlap between electron hole wave functions suppressing atomic fluctuations. The doping also widens energy gap to further reduce enhance open-circuit voltage perovskite solar cells. These factors increase charge carrier lifetime an order magnitude improve structural in series CsPbI1.88BrAc0.12 > CsPbI2Br CsPbI3. fundamental atomistic insights into anion photophysical properties lead halide perovskites guide design efficient optoelectronic materials.

Язык: Английский

---