Modeling MR-TADF Emitters: Excited-State Decay Rate Constants and Wave Function Descriptors DOI
Mariana T. do Casal,

Youssef Badawy,

Daniel Escudero

et al.

The Journal of Physical Chemistry C, Journal Year: 2024, Volume and Issue: 128(43), P. 18170 - 18181

Published: Oct. 17, 2024

Multiresonance thermally activated delayed fluorescence (MR-TADF) emitters have gained popularity given their potential of attaining negligible singlet–triplet energy gaps, i.e., ΔEST, without hindering emission, thus increasing the reverse and direct intersystem crossing rates affecting fluorescence. This is achieved due to singlet triplet states' short-range charge transfer character (SRCT). Thus, obtaining quantitative information about SRCT would help develop new MR-TADF emitters. work studies three different families emitters: DOBOA, DiKTa, OQAO. First, we compute adiabatic ΔEST with four methods (TDA-CAM-B3LYP, STEOM-DLPNO-CCSD, ADC(2), SCS-CC2). Then, (kr), (kISC), rate constants. For kr, assessed effect levels approximations on calculations. We show that kr does not depend significantly harmonic models (adiabatic Hessian or vertical Hessian), coordinate systems, broadening widths. Moreover, Herzberg–Teller effects are for but main contribution kISC kRISC. The computed constants agree well experimental results. propose use two wave function descriptors, Qat LOCa, based 1-particle transition density matrix, which assigns amount centered atoms. these descriptors transitions: S0 → S1, T1, S1 T1. studied cases, independent choice electronic structure method optimal geometry. decreases increase T1 Qat, while increases an Qat. These trends showcase how values can act as guiding design small values.

Language: Английский

Conformational Modulation of Efficient Macrocyclic Emitters Featuring Delayed Fluorescence by Conjugation Length and Cavity Dimensions DOI
Jingping Xiao, Denghui Liu, Yu Fu

et al.

Angewandte Chemie, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 19, 2024

Abstract The π‐conjugated macrocyclic emitters with thermally activated delayed fluorescence (TADF) characteristics have attracted widespread attention in the field of organic electroluminescence (EL) materials due to their unique geometries and excellent luminescence performance. Despite significant impact conjugation length cavity dimensions on molecular conformation, influence these factors excited‐state properties remains understudied. Herein, we formulated a strategy aimed at modulating conformation TADF molecules containing aniline as donor (D) unit, triazine acceptor (A), linked D−A D‐π‐A alternative construction ( MC‐TNT MC‐TST ). Corroborated by experimental theoretical analyses, compact conformationally twisted exhibits efficient blue crystalline state, facilitating EL high doping concentrations maximum external quantum efficiency (EQE max ) 13.9 %, leading emitters. Notably, π‐bridge flat demonstrates diminished Coulombic repulsion, achieving nearly 100 % photoluminescence yield superior horizontal dipole orientation 85 5 wt doped films, corresponding device‘s EQE reaches record‐high 32.7 within domain.

Language: Английский

Citations

0
Conformational Modulation of Efficient Macrocyclic Emitters Featuring Delayed Fluorescence by Conjugation Length and Cavity Dimensions DOI
Jingping Xiao, Denghui Liu, Yu Fu

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 19, 2024

Abstract The π‐conjugated macrocyclic emitters with thermally activated delayed fluorescence (TADF) characteristics have attracted widespread attention in the field of organic electroluminescence (EL) materials due to their unique geometries and excellent luminescence performance. Despite significant impact conjugation length cavity dimensions on molecular conformation, influence these factors excited‐state properties remains understudied. Herein, we formulated a strategy aimed at modulating conformation TADF molecules containing aniline as donor (D) unit, triazine acceptor (A), linked D−A D‐π‐A alternative construction ( MC‐TNT MC‐TST ). Corroborated by experimental theoretical analyses, compact conformationally twisted exhibits efficient blue crystalline state, facilitating EL high doping concentrations maximum external quantum efficiency (EQE max ) 13.9 %, leading emitters. Notably, π‐bridge flat demonstrates diminished Coulombic repulsion, achieving nearly 100 % photoluminescence yield superior horizontal dipole orientation 85 5 wt doped films, corresponding device‘s EQE reaches record‐high 32.7 within domain.

Language: Английский

Citations

0
Recent Advances in Thermally Activated Delayed Fluorescent Materials in Type II Photodynamic Therapy DOI Open Access
Jônatas Faleiro Berbigier,

Lilian C. da Luz,

Fabiano Severo Rodembusch

et al.

The Chemical Record, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 26, 2024

Abstract Photodynamic therapy (PDT) represents a novel, dual‐stage cancer treatment approach that combines light energy and photosensitizers to destroy cancerous precancerous cells through the generation of radicals (Type I) or singlet oxygen II). Since early 2010s, PDT has advanced significantly, with focus shifting toward exploration molecules capable thermally activated delayed fluorescence (TADF) as viable alternatives traditional metallic complexes organometallic compounds for producing necessary active species. TADF exhibit higher conversion efficiency, long‐lived triplet excitons, tunable photophysical properties, small singlet‐triplet gap, facilitating efficient intersystem crossing enhanced generation. As metal‐free luminophores, they offer benefits such reduced health risks, high structural flexibility, biocompatibility, which can significantly enhance efficacy. Notably, in 2019, pivotal shift occurred, researchers concentrating their efforts on identifying investing potential specifically Type II applications. This review presents innovative use materials characterized by closely spaced S 1 T orbitals, crucial PDT. Exploring these opens new avenues enhancing efficacy specificity PDT, offering promising future treatments.

Language: Английский

Citations

0
Modeling MR-TADF Emitters: Excited-State Decay Rate Constants and Wave Function Descriptors DOI
Mariana T. do Casal,

Youssef Badawy,

Daniel Escudero

et al.

The Journal of Physical Chemistry C, Journal Year: 2024, Volume and Issue: 128(43), P. 18170 - 18181

Published: Oct. 17, 2024

Multiresonance thermally activated delayed fluorescence (MR-TADF) emitters have gained popularity given their potential of attaining negligible singlet–triplet energy gaps, i.e., ΔEST, without hindering emission, thus increasing the reverse and direct intersystem crossing rates affecting fluorescence. This is achieved due to singlet triplet states' short-range charge transfer character (SRCT). Thus, obtaining quantitative information about SRCT would help develop new MR-TADF emitters. work studies three different families emitters: DOBOA, DiKTa, OQAO. First, we compute adiabatic ΔEST with four methods (TDA-CAM-B3LYP, STEOM-DLPNO-CCSD, ADC(2), SCS-CC2). Then, (kr), (kISC), rate constants. For kr, assessed effect levels approximations on calculations. We show that kr does not depend significantly harmonic models (adiabatic Hessian or vertical Hessian), coordinate systems, broadening widths. Moreover, Herzberg–Teller effects are for but main contribution kISC kRISC. The computed constants agree well experimental results. propose use two wave function descriptors, Qat LOCa, based 1-particle transition density matrix, which assigns amount centered atoms. these descriptors transitions: S0 → S1, T1, S1 T1. studied cases, independent choice electronic structure method optimal geometry. decreases increase T1 Qat, while increases an Qat. These trends showcase how values can act as guiding design small values.

Language: Английский

Citations

0