Artificial design of organic emitters via a genetic algorithm enhanced by a deep neural network

Chemical Science, Год журнала: 2024, Номер 15(7), С. 2618 - 2639

Опубликована: Янв. 1, 2024

An artificial molecular design workflow using a genetic algorithm with strings and neural networks applied to organic molecules inverted singlet-triplet gaps finds 1000 candidates appreciable fluorescence rates.

Язык: Английский

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Enhanced inverted singlet–triplet gaps in azaphenalenes and non-alternant hydrocarbons

Chemical Communications, Год журнала: 2024, Номер 60(15), С. 2070 - 2073

Опубликована: Янв. 1, 2024

A substituent-based design strategy induces and enhances inversions in the excited state singlet–triplet gaps a wide range of potential organic light-emitting molecules.

Язык: Английский

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Ultrafast Computational Screening of Molecules with Inverted Singlet–Triplet Energy Gaps Using the Pariser–Parr–Pople Semiempirical Quantum Chemistry Method

The Journal of Physical Chemistry A, Год журнала: 2024, Номер 128(12), С. 2445 - 2456

Опубликована: Март 14, 2024

Molecules with an inverted energy gap between their first singlet and triplet excited states have promising applications in the next generation of organic light-emitting diode (OLED) materials. Unfortunately, such molecules are rare, only a handful examples currently known. High-throughput virtual screening could assist finding novel classes these molecules, but current efforts hampered by high computational cost required quantum chemical methods. We present method based on semiempirical Pariser–Parr–Pople theory augmented perturbation show that it reproduces gaps at fraction employed excited-state calculations. Our study paves way for ultrahigh-throughput inverse design to accelerate discovery development this new OLED

Язык: Английский

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Experimental and computational studies of the optical properties of 2,5,8-tris(phenylthiolato)heptazine with an inverted singlet–triplet gap

Physical Chemistry Chemical Physics, Год журнала: 2024, Номер 26(7), С. 5922 - 5931

Опубликована: Янв. 1, 2024

The calculated energy inversion of the first excited states a heptazine phenylthiolate molecule is consistent with intense blue fluorescence in solid state and toluene solution.

Язык: Английский

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Computational Investigations of the Detailed Mechanism of Reverse Intersystem Crossing in Inverted Singlet–Triplet Gap Molecules

ACS Applied Materials & Interfaces, Год журнала: 2024, Номер unknown

Опубликована: Май 10, 2024

Inverted singlet–triplet gap (INVEST) materials have promising photophysical properties for optoelectronic applications due to an inversion of their lowest singlet (S1) and triplet (T1) excited states. This results in exothermic reverse intersystem crossing (rISC) process that potentially enhances harvesting, compared thermally activated delayed fluorescence (TADF) emitters with endothermic rISCs. However, the processes phenomena facilitate conversion between states INVEST are underexplored. We investigate complex potential energy surfaces (PESs) three heavily studied azaphenalene compounds, namely, cyclazine, pentazine, heptazine using two state-of-the-art computational methodologies, RMS-CASPT2 SCS-ADC(2) methods. Our findings suggest ISC rISC take place directly S1 T1 electronic all compounds through a minimum-energy point (MECP) activation barrier 0.11 0.58 eV above state 0.06 0.36 rISC. predict higher-lying not populated, since structures these energetically accessible. Furthermore, conical intersection (CI) ground is high (between 0.4 2.0 eV) which makes nonradiative decay back relatively slow process. demonstrate spin-orbit coupling (SOC) driving S1-T1 enhanced by vibronic possessing vibrational modes proper symmetry. also rationalize experimentally observed anti-Kasha emission cyclazine inaccessible CI bright S2 dark states, hindering internal conversion. Finally, we show able qualitatively reproduce features, but consistently overpredict relative energies structural minima RMS-CASPT2. The identification features elaborates design rules new improved quantum yields.

Язык: Английский

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Molecular Geometry Impact on Deep Learning Predictions of Inverted Singlet–Triplet Gaps

The Journal of Physical Chemistry A, Год журнала: 2024, Номер 128(12), С. 2417 - 2426

Опубликована: Март 14, 2024

We present a deep learning model able to predict excited singlet–triplet gaps with mean absolute error (MAE) of ≈20 meV obtain potential inverted (IST) candidates. exploit cutting-edge spherical message passing graph neural networks designed specifically for generating 3D representations in molecular learning. In nutshell, the takes as input list unsaturated heavy atom Cartesian coordinates and atomic numbers, producing output. exploited available large data collections train on ≈40,000 heterogeneous density functional theory (DFT) geometries ADC(2)/cc-pVDZ gaps. ascertain predictive power from quantitative perspective obtaining predictions test set ≈14,000 molecules, whose have been generated at DFT level (the same employed training set), GFN2-xTB level, through Molecular Mechanics. notice performance degradation upon switching lower-quality geometries, ones maintaining satisfactory results (MAE ≈ 50 MAE 180 generalized AMBER force field geometries), hinting caution when dealing specific chemical classes. Finally, we verify qualitative point view, different ≈15,000 molecules already used identify new IST molecules. obtained using both experimental X-ray candidates similar those provided by quantum methods, clear hints path toward improved performance.

Язык: Английский

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Reverse Intersystem Crossing Dynamics in Vibronically Modulated Inverted Singlet–Triplet Gap System: A Wigner Phase Space Study

The Journal of Physical Chemistry Letters, Год журнала: 2024, Номер 15(30), С. 7603 - 7609

Опубликована: Июль 19, 2024

We inspect the origin of inverted singlet-triplet gap (INVEST) and slow change in reverse intersystem crossing (rISC) rate with temperature, as recently observed. A Wigner phase space study reveals that, though INVEST is found at equilibrium geometry, variation exchange interaction doubles-excitation for other geometries harmonic region leads to non-INVEST behavior. This highlights importance nuclear degrees freedom phenomenon, this case, geometric puckering studied molecule determines associated rISC dynamics.

Язык: Английский

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Impact of Structure on Excitation Energies and S₁‐T₁ Energy Gaps of Asymmetrical Systems of Interest for Inverted Singlet‐Triplet Gaps

Journal of Computational Chemistry, Год журнала: 2025, Номер 46(8)

Опубликована: Март 26, 2025

Computational investigations of Inverted Singlet-Triplet (INVEST) emitters often rely on ADC(2) and TD-DFT excitation energies (EEs) obtained with the vertical approximation. Here, we first considered several cyclazine derivatives examine sensitivity EEs (VEEs) as well singlet-triplet gaps, ΔES1T1 to level at which ground state (S0) structure was optimized. For cyclazine, VEEs gaps from or are spread over a narrow range (< 0.064 eV) whether S0 is optimized various DFT, CCSD, RI-MP2 methods. However, for asymmetric cyclazines, depending protocol optimizing structures, not only substantially wider (up 0.75 but so 0.30 eV), leading cases where, different one obtains positive significantly negative gaps. We relate this behavior introduction significant asymmetry bond-length variations in derivatives, formed by ligand functionalization modification core. On more note, adiabatic (AEEs) display lower (7-30× less) geometry optimization protocols than their analogs. Crucially, M06-HF functional 100% non-local exchange provides closest available CCSD(T) data. show that effect exists also other frameworks (e.g., azulene, pentaazaphenalene, non-alternant polycyclic hydrocarbons) have been INVEST property, broader up 1.19 eV 0.62 eV. emitters, it therefore extremely important judiciously choose computational geometries, computing

Язык: Английский

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Double-bond delocalization in non-alternant hydrocarbons induces inverted singlet–triplet gaps

Chemical Science, Год журнала: 2023, Номер 14(38), С. 10458 - 10466

Опубликована: Янв. 1, 2023

Molecules where the first excited singlet state is lower in energy than triplet have potential to revolutionize OLEDs. This inverted singlet-triplet gap violates Hund's rule and currently there are only a few molecules which known this property. Here, we screen complete set of non-alternant hydrocarbons consisting 5-, 6-, 7-membered rings fused into two-, three- four-ring polycyclic systems. We identify several symmetry ground-state structure broken due bond-length alternation. Through symmetry-constrained optimizations molecular cores when higher symmetry, pentalene being example. uncover strategy stabilize their higher-symmetry structures with electron donors or acceptors. design substituted pentalenes, s-indacenes, indeno[1,2,3-ef]heptalenes gaps, among synthetically examples. In contrast emitters, double-bond delocalized conjugated as necessary condition achieve gap. enables chemical tuning paves way for rational gaps. These prospective emitters if properties can be optimized use

Язык: Английский

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Benchmark computations of nearly degenerate singlet and triplet states of N-heterocyclic chromophores. II. Density-based methods

The Journal of Chemical Physics, Год журнала: 2025, Номер 162(2)

Опубликована: Янв. 8, 2025

In this paper, we demonstrate the performance of several density-based methods in predicting inversion S1 and T1 states a few N-heterocyclic triangulene based fused ring molecules (popularly known as INVEST molecules) with an eye to identify well performing but cost-effective preliminary screening method. Both conventional linear-response time-dependent density functional theory (LR-TDDFT) ΔSCF (namely maximum overlap method, square-gradient minimization restricted open-shell Kohn–Sham) are considered for excited state computations using exchange–correlation (XC) functionals from different rungs Jacob’s ladder. A well-justified systematism is observed when compared against fully internally contracted multireference configuration interaction singles doubles and/or equation motion coupled-cluster (EOM-CCSD), most important feature being capture spin-polarization presence correlation. set least mean absolute error proposed both approaches, LR-TDDFT ΔSCF, which can be more alternatives on synthesizable larger derivatives templates studied here. We have our findings extensive studies three cyclazine-based molecular templates, additional six related templates. Previous benchmark subsets were conducted domain-based local pair natural orbital-similarity transformed EOM-CCSD (STEOM-CCSD), resulted inadequate evaluation due deficiencies theory. The role exact-exchange, spin-contamination, context DFT comes forefront supports numerical XC these applications. Suitable connections drawn two exciton models, minimal physics governing interactions molecules.

Язык: Английский

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