Ternary donor–acceptor phosphine oxide hosts with peculiar high energy gap for efficient blue electroluminescence

2015 ◽  
Vol 3 (36) ◽  
pp. 9469-9478 ◽  
Author(s):  
Mingzhi Sun ◽  
Liping Zhu ◽  
Wenjing Kan ◽  
Ying Wei ◽  
Dongge Ma ◽  
...  
Keyword(s):  
Phosphine Oxide ◽  
Energy Gap ◽  
High Energy ◽  
Electronic Coupling ◽  
Triplet Energy ◽  
Donor Acceptor

A triangle-shaped D–A–A molecule PCImbPO with unusually high triplet energy of 3.0 eV, enhanced D–A electronic coupling and separated FMO and triplet locations is described.

scholarly journals Correction: Ternary donor–acceptor phosphine oxide hosts with peculiar high energy gap for efficient blue electroluminescence

2015 ◽  
Vol 3 (36) ◽  
pp. 9479-9479 ◽  
Author(s):  
Mingzhi Sun ◽  
Liping Zhu ◽  
Wenjing Kan ◽  
Ying Wei ◽  
Dongge Ma ◽  
...  
Keyword(s):  
Phosphine Oxide ◽  
Energy Gap ◽  
High Energy ◽  
Donor Acceptor

Correction for ‘Ternary donor–acceptor phosphine oxide hosts with peculiar high energy gap for efficient blue electroluminescence’ by Mingzhi Sun et al., J. Mater. Chem. C, 2015, DOI: 10.1039/c5tc02029h.

scholarly journals A Novel Design Strategy for Suppressing Efficiency Roll-Off of Blue Thermally Activated Delayed Fluorescence Molecules through Donor–Acceptor Interlocking by C–C Bonds

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1735 ◽  
Author(s):  
Tae Hui Kwon ◽  
Soon Ok Jeon ◽  
Masaki Numata ◽  
Hasup Lee ◽  
Yeon Sook Chung ◽  
...  
Keyword(s):  
Energy Gap ◽  
Delayed Fluorescence ◽  
Triplet Energy ◽  
Design Synthesis ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor And Acceptor ◽  
Donor Acceptor ◽  
Display Performance ◽  
Commercial Applications

The short material lifetime of thermally activated delayed fluorescence (TADF) technology is a major obstacle to the development of economically feasible, highly efficient, and durable devices for commercial applications. TADF devices are also hampered by insufficient operational stability. In this paper, we report the design, synthesis, and evaluation of new TADF molecules possessing a sterically twisted skeleton by interlocking donor and acceptor moieties through a C–C bond. Compared to C–N-bond TADF molecules, such as CPT2, the C–C-bond TADF molecules showed a large dihedral angle increase by more than 30 times and a singlet–triplet energy-gap decrease to less than 0.22 eV because of the steric hindrance caused by the direct C–C bond connection. With the introduction of a dibenzofuran core structure, devices comprising BMK-T317 and BMK-T318 exhibited a magnificent display performance, especially their external quantum efficiencies, which were as high as 19.9% and 18.8%, respectively. Moreover, the efficiency roll-off of BMK-T318 improved significantly (26.7%). These results indicate that stability of the material can be expected through the reduction of their singlet–triplet splitting and the precise adjustment of dihedral angles between the donor–acceptor skeletons.

A study on photophysical and photodynamic properties of donor–acceptor BODIPY complexes: Correlation between singlet oxygen quantum yield and singlet-triplet energy gap

2021 ◽  
Vol 187 ◽  
pp. 109051
Author(s):  
Jae Moon Lee ◽  
Seongsoo Kang ◽  
Tae Gyu Hwang ◽  
Hong Mo Kim ◽  
Woo Sung Lee ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
Energy Gap ◽  
Triplet Energy ◽  
Donor Acceptor

scholarly journals Shallow distance-dependent triplet energy migration mediated by endothermic charge-transfer

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Runchen Lai ◽  
Yangyi Liu ◽  
Xiao Luo ◽  
Lan Chen ◽  
Yaoyao Han ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Semiconductor Nanocrystals ◽  
Electronic Coupling ◽  
Alternative Mechanism ◽  
Acceptor Pair ◽  
Triplet Energy ◽  
Distance Dependence ◽  
Donor Acceptor ◽  
Triplet Energy Transfer

AbstractConventional wisdom posits that spin-triplet energy transfer (TET) is only operative over short distances because Dexter-type electronic coupling for TET rapidly decreases with increasing donor acceptor separation. While coherent mechanisms such as super-exchange can enhance the magnitude of electronic coupling, they are equally attenuated with distance. Here, we report endothermic charge-transfer-mediated TET as an alternative mechanism featuring shallow distance-dependence and experimentally demonstrated it using a linked nanocrystal-polyacene donor acceptor pair. Donor-acceptor electronic coupling is quantitatively controlled through wavefunction leakage out of the core/shell semiconductor nanocrystals, while the charge/energy transfer driving force is conserved. Attenuation of the TET rate as a function of shell thickness clearly follows the trend of hole probability density on nanocrystal surfaces rather than the product of electron and hole densities, consistent with endothermic hole-transfer-mediated TET. The shallow distance-dependence afforded by this mechanism enables efficient TET across distances well beyond the nominal range of Dexter or super-exchange paradigms.

Effect of Substituents on the Viscosity Dependence of Fluorescence and on the S1 - T1 Energy Gap of Donor-Acceptor Substituted Trans-Stilbenes

1997 ◽  
Vol 52 (12) ◽  
pp. 837-842 ◽  
Author(s):  
Hans E. Wilhelm ◽  
Horst Gebert ◽  
Wolfgang Regenstein
Keyword(s):  
Energy Gap ◽  
Quantum Yields ◽  
Intersystem Crossing ◽  
Triplet Energy ◽  
Fluorescence Quantum Yields ◽  
Donor Acceptor ◽  
Fluorescence And Phosphorescence Spectra ◽  
Viscosity Dependence ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

The dependence of fluorescence quantum yields and S1-lifetimes of donor-acceptor substituted trans-stilbenes on temperature was measured in the temperature range from 298 to 100 K, using solutions of stilbenes in 3-methylpentane (3-MP). Measurements of fluorescence and phosphorescence spectra show that the triplet energy is almost independent of the acceptor. The S1-energy and the S1-T1 energy gap decrease with increasing acceptor strength. For all compounds intersystem crossing (ISC) S1 → T1, is negligible

scholarly journals Orientations and water dynamics of photoinduced secondary charge-separated states for magnetoreception by cryptochrome

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Misato Hamada ◽  
Tatsuya Iwata ◽  
Masaaki Fuki ◽  
Hideki Kandori ◽  
Stefan Weber ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Charge Separation ◽  
Energy Gap ◽  
Electron Tunneling ◽  
Weak Field ◽  
Magnetic Compass ◽  
Water Dynamics ◽  
Electronic Coupling ◽  
Triplet Energy ◽  
Time Resolved

AbstractIn the biological magnetic compass, blue-light photoreceptor protein of cryptochrome is thought to conduct the sensing of the Earth’s magnetic field by photoinduced sequential long-range charge-separation (CS) through a cascade of tryptophan residues, WA(H), WB(H) and WC(H). Mechanism of generating the weak-field sensitive radical pair (RP) is poorly understood because geometries, electronic couplings and their modulations by molecular motion have not been investigated in the secondary CS states generated prior to the terminal RP states. In this study, water dynamics control of the electronic coupling is revealed to be a key concept for sensing the direction of weak magnetic field. Geometry and exchange coupling (singlet–triplet energy gap: 2J) of photoinduced secondary CS states composed of flavin adenine dinucleotide radical anion (FAD−•) and radical cation WB(H)+• in the cryptochrome DASH from Xenopus laevis were clarified by time-resolved electron paramagnetic resonance. We found a time-dependent energetic disorder in 2J and was interpreted by a trap CS state capturing one reorientated water molecule at 120 K. Enhanced electron-tunneling by water-libration was revealed for the terminal charge-separation event at elevated temperature. This highlights importance of optimizing the electronic coupling for regulation of the anisotropic RP yield on the possible magnetic compass senses.

scholarly journals Molecular Design of Conjugated Small Molecule Nanoparticles for Synergistically Enhanced PTT/PDT

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Wei Shao ◽  
Chuang Yang ◽  
Fangyuan Li ◽  
Jiahe Wu ◽  
Nan Wang ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
Small Molecule ◽  
Energy Gap ◽  
Molecular Design ◽  
High Mass ◽  
Triplet Energy ◽  
Donor Acceptor

AbstractSimultaneous photothermal therapy (PTT) and photodynamic therapy (PDT) is beneficial for enhanced cancer therapy due to the synergistic effect. Conventional materials developed for synergistic PTT/PDT are generally multicomponent agents that need complicated preparation procedures and be activated by multiple laser sources. The emerging monocomponent diketopyrrolopyrrole (DPP)-based conjugated small molecular agents enable dual PTT/PDT under a single laser irradiation, but suffer from low singlet oxygen quantum yield, which severely restricts the therapeutic efficacy. Herein, we report acceptor-oriented molecular design of a donor–acceptor–donor (D–A–D) conjugated small molecule (IID-ThTPA)-based phototheranostic agent, with isoindigo (IID) as selective acceptor and triphenylamine (TPA) as donor. The strong D–A strength and narrow singlet–triplet energy gap endow IID-ThTPA nanoparticles (IID-ThTPA NPs) high mass extinction coefficient (18.2 L g−1 cm−1), competitive photothermal conversion efficiency (35.4%), and a dramatically enhanced singlet oxygen quantum yield (84.0%) comparing with previously reported monocomponent PTT/PDT agents. Such a high PTT/PDT performance of IID-ThTPA NPs achieved superior tumor cooperative eradicating capability in vitro and in vivo.

scholarly journals Thermochromic aggregation-induced dual phosphorescence via temperature-dependent sp3-linked donor-acceptor electronic coupling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tao Wang ◽  
Zhubin Hu ◽  
Xiancheng Nie ◽  
Linkun Huang ◽  
Miao Hui ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Electronic Coupling ◽  
Temperature Dependent ◽  
Molecular Systems ◽  
Donor And Acceptor ◽  
Theoretical Investigations ◽  
Donor Acceptor ◽  
And Control ◽  
Two Temperature

AbstractAggregation-induced emission (AIE) has proven to be a viable strategy to achieve highly efficient room temperature phosphorescence (RTP) in bulk by restricting molecular motions. Here, we show that by utilizing triphenylamine (TPA) as an electronic donor that connects to an acceptor via an sp3 linker, six TPA-based AIE-active RTP luminophores were obtained. Distinct dual phosphorescence bands emitting from largely localized donor and acceptor triplet emitting states could be recorded at lowered temperatures; at room temperature, only a merged RTP band is present. Theoretical investigations reveal that the two temperature-dependent phosphorescence bands both originate from local/global minima from the lowest triplet excited state (T1). The reported molecular construct serves as an intermediary case between a fully conjugated donor-acceptor system and a donor/acceptor binary mix, which may provide important clues on the design and control of high-freedom molecular systems with complex excited-state dynamics.

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