4.6 Article

Enabling red thermally activated delayed fluorescence by increasing the push-pull strength in naphthalimide-phenothiazine derivatives

Related references

Note: Only part of the references are listed.
Article Chemistry, Physical

Investigation of Thermally Activated Delayed Fluorescence in Donor-Acceptor Organic Emitters with Time-Resolved Absorption Spectroscopy

Lloyd Fisher et al.

Summary: This study investigates the excited-state dynamics of organic chromophores with thermally activated delayed fluorescent (TADF) characteristics using multiple time-resolved and nonlinear optical measurements, as well as quantum chemical simulations. The influence of a phenylene linker on the photophysical properties of emitters composed of carbazole-based donors linked to either a phthalonitrile (PN) or diphenyltriazine (Trz) acceptor is of particular interest. The results show that PN-acceptor compounds exhibit a near double-fluorescence quantum yield enhancement in oxygen-free conditions, while Trz-acceptor compounds are more efficient fluorescence emitters and quickly transition from a delocalized to localized state. Only PN-acceptor compounds display a long-lived emissive lifetime component associated with TADF activity. Nanosecond transient absorption spectra and kinetics analysis reveal long-lived excited-state absorption (ESA) bands associated with triplet states for the PN-acceptor compounds. No ESA bands are observed for the Trz-acceptor compounds, despite a quantum yield enhancement after oxygen purging. Quantum chemical calculations indicate that the inclusion of the phenylene linker prevents sufficient energy separation and suppresses TADF activity, while directly linking multiple donors to the acceptor would aid in achieving TADF activity.

CHEMISTRY OF MATERIALS (2022)

Review Chemistry, Multidisciplinary

Recent progress in thermally activated delayed fluorescence emitters for nondoped organic light-emitting diodes

Yi-Zhong Shi et al.

Summary: This review mainly discusses the application of nondoped organic light-emitting diodes (OLEDs) in high-performance devices. The thermally activated delayed fluorescence (TADF) mechanism can achieve 100% internal quantum efficiency, but the quenching of triplet excitons remains a challenge. The review analyzes the mechanism, exciton leaking channels, and molecular design strategies of TADF emitters, and provides an outlook on their future prospects.

CHEMICAL SCIENCE (2022)

Article Materials Science, Multidisciplinary

Photoluminescence and electrochemiluminescence of thermally activated delayed fluorescence (TADF) emitters containing diphenylphosphine chalcogenide-substituted carbazole donors

Shiv Kumar et al.

Summary: In order to develop efficient blue-emitting TADF compounds, derivatives of 2CzPN with electron-accepting groups were synthesized. The results showed that these derivatives shifted the emission wavelength towards blue in polar solvents and matrices. Electrochemiluminescence experiments revealed that some of these derivatives exhibited an unprecedented delayed onset and long emission times, which suggest an organic long-persistent electrochemiluminescence mechanism.

JOURNAL OF MATERIALS CHEMISTRY C (2022)

Article Chemistry, Physical

Aggregation-Induced Emission in Phenothiazine-Based Fluorophores: An Insight into the Excited State and Aggregate Formation Mechanism

Alessio Cesaretti et al.

Summary: This study reports the evidence of emissive aggregates of push-pull phenothiazine and phenothiazine dioxide derivatives. These aggregates show promise for applications in biology and material science. The study investigates the aggregation-induced emission (AIE) mechanism through time-resolved spectroscopy and advanced data analysis. The results demonstrate significant AIE behavior activated by the restriction of intramolecular rotations. The aggregates also exhibit notable emission upon two-photon excitation and have potential as novel fluorophores for bioimaging.

JOURNAL OF PHYSICAL CHEMISTRY C (2022)

Review Chemistry, Multidisciplinary

A Brief History of OLEDs-Emitter Development and Industry Milestones

Gloria Hong et al.

Summary: Organic light-emitting diodes (OLEDs) have undergone significant development over the past 30 years, with advancements in emitter materials leading to three generations of OLED devices. Research is now focused on the fourth generation of OLEDs, with academia and industry achieving milestones in the development of green, orange-red, and blue OLED emitters.

ADVANCED MATERIALS (2021)

Article Chemistry, Multidisciplinary

Highly Efficient Near-Infrared Electrofluorescence from a Thermally Activated Delayed Fluorescence Molecule

Umamahesh Balijapalli et al.

Summary: The study demonstrates a highly efficient NIR emitter with thermally activated delayed fluorescence (TADF) and its application to NIR-OLEDs, achieving unprecedented EQE of 13.4% with a peak wavelength at 734 nm. The TPA-PZTCN emitter can sensitize a deeper NIR fluorophore to achieve an EQE of over 1% in a TADF-sensitized NIR-OLED with high operational durability.

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION (2021)

Review Chemistry, Multidisciplinary

Small-molecule based thermally activated delayed fluorescence materials with dual-emission characteristics

Xuping Li et al.

Summary: By designing organic donor-acceptor TADF compounds with dual-emission characteristics, the potential applications of these materials in modern luminescence-related fields can be expanded, such as in multicolor luminescence and multi-functional luminescent probes.

SCIENCE CHINA-CHEMISTRY (2021)

Article Chemistry, Physical

Improving reverse intersystem crossing in exciplex-forming hosts by introducing heavy atom effect

T. Huang et al.

Summary: The influence of heavy atom effect on the reverse intersystem crossing rate (kRISC) of exciplex is investigated in this study, and it is found that bromine (Br)-substituted acceptors can enhance the kRISC process of exciplex.

MATERIALS TODAY ENERGY (2021)

Article Chemistry, Multidisciplinary

Acceptor-Donor-Acceptor-Type Orange-Red Thermally Activated Delayed Fluorescence Materials Realizing External Quantum Efficiency Over 30% with Low Efficiency Roll-Off

Durai Karthik et al.

Summary: Two new orange-red TADF materials, PzTDBA and PzDBA, exhibit high efficiency, low roll-off, and long lifetime. These materials are designed based on the A-D-A molecular configuration, which contributes to their good electronic properties.

ADVANCED MATERIALS (2021)

Article Nanoscience & Nanotechnology

Charge Transfer as the Key Parameter Affecting the Color Purity of Thermally Activated Delayed Fluorescence Emitters

Ramin Ansari et al.

Summary: The emission bandwidth of thermally activated delayed fluorescence (TADF) is primarily determined by the charge transfer character of the molecule, rather than its propensity for rotational motion. Rational molecular design can result in organic emitters exhibiting sharp emission spectra.

ACS APPLIED MATERIALS & INTERFACES (2021)

Article Chemistry, Multidisciplinary

Tetrabenzo[a,c]phenazine Backbone for Highly Efficient Orange-Red Thermally Activated Delayed Fluorescence with Completely Horizontal Molecular Orientation

Umamahesh Balijapalli et al.

Summary: Three TADF molecules PQ1, PQ2, and PQ3, featuring planar acceptor manipulation and high steric hindrance, exhibit high molecular rigidity that suppresses nonradiative decay of excitons, leading to improved photoluminescence quantum yields. PQ3, with well-aligned excited states, enhances reverse intersystem crossing rate constant and displays a high external EL quantum efficiency in the orange-red OLED.

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION (2021)

Article Chemistry, Multidisciplinary

Realizing Record-High Electroluminescence Efficiency of 31.5 % for Red Thermally Activated Delayed Fluorescence Molecules

Zheyi Cai et al.

Summary: Tailor-made red TADF molecules with intramolecular hydrogen bonding show NIR emissions in neat films and red delayed fluorescence in doped films, with high photoluminescence quantum yields. They exhibit high optical out-coupling factors due to their horizontal orientation in films. The non-doped OLEDs emit NIR lights with maximum external quantum efficiencies, while doped OLEDs achieve record-breaking efficiency levels with red lights emission. These new red TADF materials have great potentials in display and lighting devices.

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION (2021)

Article Chemistry, Multidisciplinary

Tuning the Fluorescence and the Intramolecular Charge Transfer of Phenothiazine Dipolar and Quadrupolar Derivatives by Oxygen Functionalization

Yogajivan Rout et al.

Summary: The effect of the oxidation state of sulfur in naphthalimide and phenothiazine-based push-pull systems on their spectral, photophysical, and electrochemical properties was investigated. Oxygen functionalization significantly improved the optical and nonlinear optical features of the molecules, suggesting a new effective synthetic strategy for tailored photophysics of phenothiazine-based organic materials for various optoelectronic applications.

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY (2021)

Article Chemistry, Multidisciplinary

Aggregation-induced delayed fluorescence luminogens: the innovation of purely organic emitters for aqueous electrochemiluminescence

Baohua Zhang et al.

Summary: This study introduces a new aqueous electrochemiluminescence (ECL) technique based on aggregation-induced delayed fluorescence (AIDF) luminogens. Compared with traditional organic AIE luminogens, AIDF luminogens show higher ECL efficiency.

CHEMICAL SCIENCE (2021)

Article Chemistry, Multidisciplinary

Molecular design of thermally activated delayed fluorescent emitters for narrowband orange-red OLEDs boosted by a cyano-functionalization strategy

Yang Liu et al.

Summary: By attaching a cyano functionality at the lowest unoccupied molecular orbital location of the MR-TADF skeleton, the red-shifted emission and good color purity of orange-red MR-TADF emitters can be achieved. The coplanar conformation of the CN group helps to restrict structure relaxation and maintain the high-quality emission characteristics in orange-red TADF-OLEDs.

CHEMICAL SCIENCE (2021)

Article Materials Science, Multidisciplinary

Novel anti-Kasha fluorophores exhibiting dual emission with thermally activated delayed fluorescence through detouring triplet manifolds

Byung Hak Jhun et al.

Summary: Molecules displaying dual emission, disobeying Kasha's rule, have been discovered in a novel series of dyads composed of coumarin and cyclic donors, showing short-wavelength prompt fluorescence and long-wavelength delayed fluorescence. Mechanistic studies reveal that the dual emission originates from specific transition states and is influenced by conformeric heterogeneity. The findings point to a coupling between the photophysical processes of dual emission and thermally activated delayed fluorescence.

JOURNAL OF MATERIALS CHEMISTRY C (2021)

Article Materials Science, Multidisciplinary

High efficiency and long lifetime orange-red thermally activated delayed fluorescent organic light emitting diodes by donor and acceptor engineering

Shantaram Kothavale et al.

Summary: Highly efficient and stable TADF emitters are needed for commercial applications, but achieving high EQE and long lifetime in a single organic molecular design is difficult, especially in long wavelength designs. Two orange-red TADF emitters, 6,7-DCNQx-DICz and 5,8-DCNQx-DICz, were designed and synthesized, with 6,7-DCNQx-DICz achieving a higher EQE of 23.9% and a lifetime of 931 hours, while 5,8-DCNQx-DICz had a lower EQE of 12.5%, but a longer lifetime of 1184 hours. The combination of DICz and DCQx units could be a promising chemical platform for future highly efficient and long lifetime orange-red TADF OLED designs.

JOURNAL OF MATERIALS CHEMISTRY C (2021)

Article Chemistry, Multidisciplinary

Using fluorene to lock electronically active moieties in thermally activated delayed fluorescence emitters for high-performance non-doped organic light-emitting diodes with suppressed roll-off

Lin Wu et al.

Summary: This study designed two TADF emitters SPBP-DPAC and SPBP-SPAC by modifying a less successful emitter BP-DPAC with extra fluorenes to increase intermolecular distances and attenuate electron-exchange interaction, resulting in significantly higher exciton utilization in non-doped films. The non-doped OLEDs based on SPBP-DPAC and SPBP-SPAC showed excellent maximum external quantum efficiency and negligible roll-offs at practical brightness, indicating a feasible molecular modification strategy to enhance AIE-TADF emitters' performance in OLEDs.

CHEMICAL SCIENCE (2021)

Article Chemistry, Multidisciplinary

New Direct Approach for Determining the Reverse Intersystem Crossing Rate in Organic Thermally Activated Delayed Fluorescent (TADF) Emitters

Ricardo Javier Vazquez et al.

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY (2020)

Article Materials Science, Multidisciplinary

White-light electroluminescence from a layer incorporating a single fully-organic spiro compound with phosphine oxide substituents

P. Tourneur et al.

JOURNAL OF MATERIALS CHEMISTRY C (2020)

Review Materials Science, Multidisciplinary

Purely Organic Materials with Aggregation-Induced Delayed Fluorescence for Efficient Nondoped OLEDs

Jingjing Guo et al.

ADVANCED OPTICAL MATERIALS (2018)

Review Nanoscience & Nanotechnology

All-organic thermally activated delayed fluorescence materials for organic light-emitting diodes

Yuchao Liu et al.

NATURE REVIEWS MATERIALS (2018)

Review Chemistry, Analytical

Photophysics of thermally activated delayed fluorescence molecules

Fernando B. Dias et al.

METHODS AND APPLICATIONS IN FLUORESCENCE (2017)

Article Chemistry, Multidisciplinary

Purely Organic Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes

Michael Y. Wong et al.

ADVANCED MATERIALS (2017)

Article Chemistry, Physical

Experimental evidence of dual emission in a negatively solvatochromic push-pull pyridinium derivative

B. Carlotti et al.

PHYSICAL CHEMISTRY CHEMICAL PHYSICS (2015)

Article Multidisciplinary Sciences

Highly efficient organic light-emitting diodes from delayed fluorescence

Hiroki Uoyama et al.

NATURE (2012)