Enhancing Reverse Intersystem Crossing in TSCT-TADF Emitters: Heavy Atom Modulation of Multiresonance Acceptors DOI

Jikai Yu,

Jia Tang,

Zhiying Ma

и другие.

The Journal of Physical Chemistry A, Год журнала: 2025, Номер unknown

Опубликована: Янв. 3, 2025

With the rapid development of thermally activated delayed fluorescence (TADF) materials, achieving efficient reverse intersystem crossing (RISC) to mitigate triplet–triplet annihilation has emerged as a prominent research focus. This study investigates five derivative molecules, featuring varied bridging atoms/groups (O, S, Se, −CH2−), designed from reported TADF molecule AC-BO with through-space charge transfer (TSCT) properties. Utilizing time-dependent density functional theory coupled PCM solution model, their excited state behaviors were simulated in toluene environment. Interestingly, it was observed that RISC and one derivative, AC-BCO, occurs predominantly via T2 rather than typical T1 (3LEB, where B denotes fluorene bridge), distinguishing conventional TSCT-TADF compounds, typically involves transitions between 3CT 1CT states. distinctive mode is attributed reduced spin–orbit coupling (SOC) 3LEB, representing significant contributor process through its character. Introduction heavy atoms enhances electron-withdrawing ability acceptor unit, leading exhibiting 3MRCT characteristics increased SOC, thereby favoring transitions. not only deepens our understanding transition mechanisms compounds but also provides crucial insights into molecular design regulation triplet

Язык: Английский

Triplet–triplet annihilation photon upconversion-mediated photochemical reactions DOI
Ling Huang, Gang Han

Nature Reviews Chemistry, Год журнала: 2024, Номер 8(4), С. 238 - 255

Опубликована: Март 21, 2024

Язык: Английский

Процитировано

35

Imidazophenothiazine-Based Thermally Activated Delayed Fluorescence Materials with Ultra-Long-Lived Excited States for Energy Transfer Photocatalysis DOI
Ryoga Hojo, Katrina Bergmann, Seja A. Elgadi

и другие.

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(33), С. 18366 - 18381

Опубликована: Авг. 9, 2023

Triplet-triplet energy transfer (EnT) is a powerful activation pathway in photocatalysis that unlocks new organic transformations and improves the sustainability of synthesis. Many current examples, however, still rely on platinum-group metal complexes as photosensitizers, with associated high costs environmental impacts. Photosensitizers exhibit thermally activated delayed fluorescence (TADF) are attractive fully alternatives EnT photocatalysis. However, TADF photocatalysts incorporating heavy atoms remain rare, despite their utility inducing efficient spin-orbit-coupling, intersystem-crossing, consequently triplet population. Here, we describe synthesis imidazo-phenothiazine (IPTZ), sulfur-containing heterocycle locked planar structure shallow LUMO level. This acceptor used to prepare seven TADF-active energies up 63.9 kcal mol-1. We show sulfur incorporation spin-orbit coupling increases lifetimes 3.64 ms, while also allowing for tuning photophysical properties via oxidation at atom. These IPTZ materials applied five seminal reactions: [2 + 2] cycloaddition, disulfide-ene reaction, Ni-mediated C-O C-N cross-coupling afford etherification, esterification, amination products, outcompeting industry-standard photocatalyst 2CzPN four studied scenarios. Detailed theoretical studies understand structure-activity relationships demonstrate key role atom effect design superior photocatalytic performance.

Язык: Английский

Процитировано

42

Narrowband emission: organic thermally-activated delayed fluorescence materials and underlying mechanisms DOI
Chunyan Lv, Xiaoqing Wang, Qing Zhang

и другие.

Materials Chemistry Frontiers, Год журнала: 2023, Номер 7(14), С. 2809 - 2827

Опубликована: Янв. 1, 2023

The underlying molecular-level insights into the structure–property relationship for narrowband emission, high photoluminescence efficiency and emission color tunability of organic MR-TADF emitters are organized both in experiment theory.

Язык: Английский

Процитировано

33

Precise modulation of multiple resonance emitters toward efficient electroluminescence with pure-red gamut for high-definition displays DOI Creative Commons

Yan‐Yun Jing,

Nengquan Li, Xiaosong Cao

и другие.

Science Advances, Год журнала: 2023, Номер 9(30)

Опубликована: Июль 28, 2023

Multiple resonance (MR) compounds have garnered substantial attention for their prospective utility in wide color gamut displays. Nevertheless, developing red MR emitters with both high efficiency and saturated emission remains demanding. We herein introduce a comprehensive strategy spectral tuning the region by simultaneously regulating π-conjugation electron-donating strengths of double boron-embedded skeleton while preserving narrowband characteristics. The proof-of-concept materials manifested emissions from orange-red to deep red, bandwidths below 0.12 eV. pure-red device based on CzIDBNO displayed superior purity CIE coordinates (0.701, 0.298), approaching Broadcast Television 2020 standard. In concert photoluminescence quantum yield strong horizontal dipole orientation, also achieved maximum external 32.5% current 20.2 cd A-1, outstripping prior reported organic light-emitting diodes (OLEDs) CIEx exceeding 0.68. These findings offer roadmap designing high-performance exceptional future OLED material research advancements.

Язык: Английский

Процитировано

25

Blue TADF Conjugated Polymers with Multi‐Resonance Feature toward Solution‐Processable Narrowband Blue OLEDs DOI
Wenbo Luo, Tao Wang, Zhongyan Huang

и другие.

Advanced Functional Materials, Год журнала: 2023, Номер 34(6)

Опубликована: Окт. 25, 2023

Abstract The development of thermally activated delayed fluorescence (TADF) polymers with narrowband emission, particularly in the blue region, remains a formidable challenge. Herein, new approach is demonstrated for TADF conjugated by integrating multiresonance moiety into backbone. All exhibit characteristics emission full‐width at half‐maximums (FWHMs) 23 nm. solution‐processed OLEDs based on these achieve maximum external quantum efficiency (EQE max ) 17.9% peak 479 nm and FWHM 28 main‐chain type MR‐TADF polymer shed light emissive polymers.

Язык: Английский

Процитировано

24

Peripheral Selenium Modification of Multi‐Resonance Thermally Activated Delayed Fluorescence Molecules for High‐Performance Blue Organic Light‐Emitting Diodes DOI

Jibiao Jin,

Shumeng Wang, He Jiang

и другие.

Advanced Optical Materials, Год журнала: 2024, Номер 12(11)

Опубликована: Фев. 28, 2024

Abstract Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) molecules have attracted much attention in the academia owing to their unique photoelectrical properties. However, MR‐TADF emitters usually show slow reverse intersystem crossing (RISC) rate, resulting high efficiency roll‐off of organic light‐emitting diodes (OLEDs) and seriously limiting further development. Here, a peripheral selenium (Se) modification is presented for promote RISC process while keeping narrowband emission high‐performance blue OLEDs. Compared parent (NBN t BuNBN), SeNBN Se BuNBN exhibited narrower full‐width at half maximum (FWHM) value 23 nm more obvious properties with up 86%, shorter lifetime 2.4 µs as well faster rate 3.34×10 5 s −1 . Therefore, OLEDs based on these two modified are achieved external quantum (EQE) 25.5% extremely suppressed roll‐offs 3.9% 100 cd m −2 24.4% 1000 This work demonstrated that introduction atom can achieve semiconductors both fast constant optoelectronic devices.

Язык: Английский

Процитировано

14

Quantum Dot-Sensitized Triplet–Triplet Annihilation Photon Upconversion for Solar Energy Conversion and beyond DOI Open Access
Zhiyuan Huang, Chen‐Ho Tung, Li‐Zhu Wu

и другие.

Accounts of Materials Research, Год журнала: 2024, Номер 5(2), С. 136 - 145

Опубликована: Фев. 7, 2024

ConspectusThe Nobel Prize in Chemistry 2023 was awarded to Moungi G. Bawendi, Louis E. Brus, and Aleksey Ekimov for the discovery synthesis of quantum dots (QDs). Since QDs 1980s, endeavors have been put improve synthetic strategies with controllable sizes, crystal structures, surfaces. With development about half a century, used multiple optoelectronic applications, which are based on conversion between one photon exciton. In this case, photons energies lower than bandgap cannot be absorbed by semiconductors. For example, solar cells or photocatalysts transparent sub-bandgap near-infrared (NIR) light spectrum, rendering transmission loss.Photon upconversion (PUC), combination low-energy high-energy one, plays critical role reshaping spectrum mitigating energy loss. Among different achieve PUC, QD sensitized triplet–triplet annihilation PUC exhibits high response irradiation, makes it an ideal strategy conversion.Here, we introduce QD-sensitized emphasize how is applied conversion. This Account starts introduction acting as active materials directly convert electricity chemical bonds due strong absorptivity, flexible tunable surface chemistry, capability accommodating transferring electrons/holes. Then move can upconvert NIR under one-sun condition. We discuss deconvolution total QY into efficiencies triplet transfer from sensitizers organic emitters, annihilation, singlet emission emitters. Next, summarize progress PUC-enhanced photovoltaics photochemical reactions. photovoltaics, two examples that beyond 1100 nm, possible couple Si-based cells. reactions, discussion separated visible-to-ultraviolet ultraviolet light-triggered reactions NIR-to-visible visible last section, point out challenges future directions field. low solid-state reabsorption must overcome photovoltaic application, more types PUC-assisted explored. also propose other potential applications such biological imaging phototherapy. hope will help readers understand systems promote application efficient beyond.

Язык: Английский

Процитировано

12

Phosphine oxide balanced charge transfer hybridization in multi-resonance emitters: towards ∼40% external quantum efficiency and preserved color purity DOI
Su Chen, Yidan Wang, Jincheng Lin

и другие.

Chemical Engineering Journal, Год журнала: 2024, Номер 489, С. 151517 - 151517

Опубликована: Апрель 22, 2024

Язык: Английский

Процитировано

10

Hyperconjugation Engineering of π-Extended Azaphosphinines for Designing Tunable Thermally Activated Delayed Fluorescence Emitters DOI
Zhaoxin Liu, Lingqiang Meng, Yanrong Jiang

и другие.

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 20, 2025

Implanting heteroatoms into organic π-conjugated molecules (OCMS) offered a great opportunity to fine-tune the chemical structures and optoelectronic properties. This work describes new family of 1,4-azaphosphinines with extended σ–π hyperconjugations. The photophysical studies revealed that azaphosphinines exhibited narrow-band thermally activated delayed fluorescence (TADF) ( full width at half-maximum: 26–40 nm). According orbital localization analysis natural bond analysis, effective σ*−π* hyperconjugation is believed induce multiple-resonance (MR) TADF, which distinct from p−π conjugation-induced MR-TADF in BN systems. Although having large ΔES1–T1s (>3.0 ev), study suggested σ*−π endowed system structural vibration favorable for spin-vibronic-assisted RISC. Having tunable p-centers (lp, O, S, Se, Me+), showed fine-tuned TADF. Generally, strong hyperconjugations small ΔES1–T1s, efficient RISCs, high PLQYs. Leveraging on hyperconjugations, TADF emission spanned UV-blue green. Particularly, photoluminescence quantum yields (74% toluene 92% 10% doped PMMA). As proof concept, two PO center were applied as light-emitting materials lighting-emitting diodes. devices UV- deep-blue EQE 10.3%. current us strategy, namely, hyperconjugation-induced MR-TADF, designing OCMs

Язык: Английский

Процитировано

2

High‐Performance Narrowband OLED with Low Efficiency Roll‐Off Based on Sulfur‐Incorporated Organoboron Emitter DOI
Deli Li, Mengke Li, Denghui Liu

и другие.

Advanced Optical Materials, Год журнала: 2023, Номер 11(24)

Опубликована: Июль 21, 2023

Abstract Multi‐resonance (MR) based organoboron emitters exhibiting high‐efficiency narrowband thermally activated delayed fluorescence (TADF) have become a critical material component for constructing high‐performance organic light‐emitting diodes (OLEDs) with high color purity and gamut. However, most of the MR‐TADF devices suffer from severe efficiency roll‐off at current density due to relatively large singlet–triplet splitting energy, long excited state lifetime, slow reverse intersystem crossing rate ( k RISC ). Herein, by utilizing sulfur atom‐fused donor unit, 7 H ‐benzo[4,5]thieno[2,3‐b]carbazole, an boron emitter (BTC‐BNCz) capable low TADF emission is developed. Benefitting heavy atom effect atom, up 1.6 × 10 5 s −1 achieved, which could greatly reduce undesired quenching effect. Consequently, OLED using BTC‐BNCz as dopant exhibits external quantum (EQE) 27.0% full width half maximum (FWHM) 35 nm. Moreover, horizontal dipole ratio assistant host, outstanding device performance achieved EQE 35.2% FWHM 37 nm, featuring roll‐off.

Язык: Английский

Процитировано

22