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1.
Angew Chem Int Ed Engl ; 60(49): 25878-25883, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34585471

RESUMO

The conformational distribution and mutual interconversion of thermally activated delayed fluorescence (TADF) emitters significantly affect the exciton utilization. However, their influence on the photophysics in amorphous film states is still not known due to the lack of a suitable quantitative analysis method. Herein, we used temperature-dependent time-resolved photoluminescence spectroscopy to quantitatively measure the relative populations of the conformations of a TADF emitter for the first time. We further propose a new concept of "self-doping" for realizing high-efficiency nondoped OLEDs. Interestingly, this "compositionally" pure film actually behaves as a film with a dopant (quasi-equatorial form) in a matrix (quasi-axial form). The concentration-induced quenching that may occur at high concentrations is thus expected to be effectively relieved. The "self-doping" OLED prepared with the newly developed TADF emitter TP2P-PXZ as a neat emitting layer realizes a high maximum external quantum efficiency of 25.4 % and neglectable efficiency roll-off.

2.
Chem Commun (Camb) ; 57(40): 4902-4905, 2021 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-33870972

RESUMO

A bromine-substituted thermally activated delayed fluorescent (TADF) molecule AQCzBr2 is designed with both small singlet-triplet splitting (ΔEST) and increased spin-orbit coupling (SOC) to boost intersystem crossing (ISC) for singlet oxygen generation. AQCzBr2 nanoparticles (NPs) demonstrate high productivity of singlet oxygen generation (ΦΔ = 0.91) which allows highly efficient photodynamic therapy toward cancer cells.

3.
Angew Chem Int Ed Engl ; 60(5): 2478-2484, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33080106

RESUMO

Developing red thermally activated delayed fluorescence (TADF) emitters for high-performance OLEDs is still facing great challenge. Herein, three red TADF emitters, pDBBPZ-DPXZ, pDTBPZ-DPXZ, and oDTBPZ-DPXZ, are designed and synthesized with same donor-acceptor (D-A) backbone with different peripheral groups attaching on the A moieties. Their lowest triplet states change from locally excited to charge transfer character leading to significantly enhance reverse intersystem crossing process. In particular, oDTBPZ-DPXZ exhibits efficient TADF feature and exciton utilization. It not only achieves an external quantum efficiency (EQE) of 20.1 % in red vacuum-processed OLED, but also realize a high EQE of 18.5 % in a solution-processed OLED, which is among the best results in solution-processed red TADF OLEDs. This work provides an effective strategy for designing red TADF molecules by managing energy level alignments to facilitate the up-conversion process and thus enhance exciton harvesting.

4.
ACS Nano ; 14(8): 9917-9928, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32706236

RESUMO

Effective multimodality phototheranostics under deep-penetration laser excitation is highly desired for tumor medicine, which is still at a deadlock due to lack of versatile photosensitizers with absorption located in the long-wavelength region. Herein, we demonstrate a stable organic photosensitizer nanoparticle based on molecular engineering of benzo[c]thiophene (BT)-based photoactivated molecules with strong wavelength-tunable absorption in the near-infrared region. Via molecular design, the absorption and singlet oxygen generation of BT molecules would be reliably tuned. Importantly, the nanoparticles with a red-shifted absorption peak of 843 nm not only show over 10-fold reactive oxygen species yield compared with indocyanine green but also demonstrate a notable photothermal effect and photoacoustic signal upon 808 nm excitation. The in vitro and in vivo experiments substantiate good multimodal anticancer efficacy and imaging performance of BT theranostics. This work provides an organic photosensitizer nanoparticle with long-wavelength excitation and high photoenergy conversion efficiency for multimodality phototherapy.


Assuntos
Nanopartículas , Fármacos Fotossensibilizantes , Fototerapia , Espécies Reativas de Oxigênio , Nanomedicina Teranóstica
5.
Small ; 16(34): e2002672, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32697430

RESUMO

Multi-modality imaging-guided cancer therapy is considered as a powerful theranostic platform enabling simultaneous precise diagnosis and treatment of cancer. However, recently reported multifunctional systems with multiple components and sophisticate structures remain major obstacles for further clinical translation. In this work, a single-photomolecular theranostic nanoplatform is fabricated via a facile nanoprecipitation strategy. By encapsulating a semiconductor oligomer (IT-S) into an amphiphilic lipid, water-dispersible IT-S nanoparticles (IT-S NPs) are prepared. The obtained IT-S NPs have a very simple construction and possess ultra-stable near-infrared (NIR) fluorescence (FL)/photoacoustic (PA) dual-modal imaging and high photothermal conversion efficiency of 72.3%. Accurate spatiotemporal distribution profiles of IT-S NPs are successfully visualized by NIR FL/PA dual-modal imaging. With the comprehensive in vivo imaging information provided by IT-S NPs, tumor photothermal ablation is readily realized under precise manipulation of laser irradiation, which greatly improves the therapeutic efficacy without any obvious side effects. Therefore, the IT-S NPs allow high tumor therapeutic efficacy under the precise guidance of FL/PA imaging techniques and thus hold great potential as an effective theranostic platform for future clinical applications.


Assuntos
Hipertermia Induzida , Nanopartículas , Neoplasias , Técnicas Fotoacústicas , Linhagem Celular Tumoral , Humanos , Neoplasias/diagnóstico por imagem , Neoplasias/terapia , Imagem Óptica , Fototerapia , Nanomedicina Teranóstica
6.
ACS Nano ; 13(11): 12901-12911, 2019 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-31682416

RESUMO

We developed a biodegradable photothermal therapeutic (PTT) agent, π-conjugated oligomer nanoparticles (F8-PEG NPs), for highly efficient cancer theranostics. By exploiting an oligomer with excellent near-infrared (NIR) absorption, the nanoparticles show a high photothermal conversion efficiency (PCE) up to 82%, surpassing those of reported inorganic and organic PTT agents. In addition, the oligomer nanoparticles show excellent photostability and good biodegradability. The F8-PEG NPs are also demonstrated to have excellent biosafety and PTT efficacy both in vitro and in vivo. This contribution not only proposes a promising oligomer-based PTT agent but also provides insight into developing highly efficient nanomaterials for cancer theranostics.


Assuntos
Nanopartículas/química , Neoplasias/terapia , Fototerapia , Nanomedicina Teranóstica , Células A549 , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Células HeLa , Humanos , Camundongos , Nanopartículas/metabolismo , Neoplasias/patologia
7.
Small ; 15(38): e1903121, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31379108

RESUMO

The combination of diagnostic and therapeutic functions in a single theranostic nanoagent generally requires the integration of multi-ingredients. Herein, a cytotoxic near-infrared (NIR) dye (IR-797) and its nanoassembly are reported for multifunctional cancer theranostics. The hydrophobic IR-797 molecules are self-assembled into nanoparticles, which are further modified with an amphiphilic polymer (C18PMH-PEG5000) on the surface. The prepared PEG-IR-797 nanoparticles (PEG-IR-797 NPs) possess inherent cytotoxicity from the IR-797 dye and work as a chemotherapeutic drug which induces apoptosis of cancer cells. The IR-797 NPs are found to have an ultrahigh mass extinction coefficient (444.3 L g-1 cm-1 at 797 nm and 385.9 L g-1 cm-1 at 808 nm) beyond all reported organic nanomaterials (<40 L g-1 cm-1 ) for superior photothermal therapy (PTT). In addition, IR-797 shows some aggregation-induced-emission (AIE) properties. Combining the merits of good NIR absorption, high photothermal energy conversion efficiency, and AIE, makes the PEG-IR-797 NPs useful for multimodal NIR AIE fluorescence, photoacoustic, and thermal imaging-guided therapy. The research exhibits the possibility of using a single ingredient and entity to perform multimodal NIR fluorescence, photoacoustic, and thermal imaging-guided chemo-/photothermal combination therapy, which may trigger wide interest from the fields of nanomedicine and medicinal chemistry to explore multifunctional theranostic organic molecules.


Assuntos
Antineoplásicos/química , Nanomedicina Teranóstica/métodos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Técnicas Fotoacústicas/métodos , Fotoquimioterapia/métodos , Polímeros/química
8.
Angew Chem Int Ed Engl ; 58(41): 14660-14665, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31313424

RESUMO

Developing red thermally activated delayed fluorescence (TADF) emitters, attainable for both high-efficient red organic light-emitting diodes (OLEDs) and non-doped deep red/near-infrared (NIR) OLEDs, is challenging. Now, two red emitters, BPPZ-PXZ and mDPBPZ-PXZ, with twisted donor-acceptor structures were designed and synthesized to study molecular design strategies of high-efficiency red TADF emitters. BPPZ-PXZ employs the strictest molecular restrictions to suppress energy loss and realizes red emission with a photoluminescence quantum yield (ΦPL ) of 100±0.8 % and external quantum efficiency (EQE) of 25.2 % in a doped OLED. Its non-doped OLED has an EQE of 2.5 % owing to unavoidable intermolecular π-π interactions. mDPBPZ-PXZ releases two pyridine substituents from its fused acceptor moiety. Although mDPBPZ-PXZ realizes a lower EQE of 21.7 % in the doped OLED, its non-doped device shows a superior EQE of 5.2 % with a deep red/NIR emission at peak of 680 nm.

9.
ACS Appl Mater Interfaces ; 11(32): 29086-29093, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31329407

RESUMO

Development of red thermally activated delayed fluorescence (TADF) emitters has been lagging behind when compared with those of blue and green fluorophores, especially for solution-processable ones. In this work, two novel orange-red TADF emitters 3,6-di(10H-phenoxazin-10-yl)dibenzo[a,c]phenazine (DBPZ-DPXZ) and 10,10'-(11,12-bis(3,5-di-tert-butylphenyl)dibenzo[a,c]phenazine-3,6-diyl)bis(10H-phenoxazine) (tDBBPZ-DPXZ) are developed. A high-performance orange-red TADF emitter, DBPZ-DPXZ, is first prepared by connecting a rigid acceptor and two rigid donor segments. While this design strategy endows DBPZ-DPXZ with an excellent TADF performance leading to a vacuum-processed organic light-emitting diode (OLED) with a high external quantum efficiency (EQE) of 17.8%, the rigid segments limit its solubility and applications in solution-processed devices. Based on this prototype, tDBBPZ-DPXZ is designed with the addition of 3,5-di-tert-butylphenyl groups to boost its solubility with barely an influence on the photophysical properties. In particular, tDBBPZ-DPXZ maintains nearly an identical photoluminescence quantum yield of 83% and singlet-triplet energy splitting of 0.03 eV with EQE of 17.0% in a vacuum-processed orange-red OLED. Furthermore, it can be applied on the orange-red solution-processed OLED realizing an EQE as high as 10.1%, representing one of the state-of-the-art results of the reported orange-red solution-processed TADF-OLEDs. This work provides an effective strategy to address the conflicting requirements between high efficiency and good solubility and develop efficient soluble orange-red TADF emitters.

10.
ACS Appl Mater Interfaces ; 11(12): 11691-11698, 2019 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-30838854

RESUMO

Phosphorescence/fluorescence hybrid white organic light-emitting diodes (OLEDs) are highly appealing for solid-state lighting. One major challenge is how to fully utilize the electrically generated excitons for light output. Herein, an efficient strategy to realize full exciton radiation is successfully revealed by a judicious molecular design and suitable device engineering. A blue host emitter TP-PPI is designed and synthesized, exhibiting a near 100% photoluminescence quantum yield and a high triplet energy level, enabling high-performance blue fluorescence and sensitization of a yellow phosphorescent dopant. Full exciton radiation in hybrid white OLEDs is demonstrated with a single emitting layer formed by doping a yellow phosphor (PO-01) into TP-PPI. Near 100% exciton utilization and state-of-the-art external quantum efficiency of 27.5% are achieved with the high-efficiency blue-emitting host and an electron-trap engineered device architecture.

11.
Front Chem ; 7: 17, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30746361

RESUMO

Carbazole (Cz) is the one of the most popular electron donors to develop thermally activated delayed fluorescence (TADF) emitters, but additional groups are generally required in the molecules to enhance the steric hindrance between Cz and electron acceptor segments. To address this issue, we replaced Cz with its derivative 1,3,6,8-tetramethyl-carbazole (tMCz) to develop TADF emitters. Two novel compounds, 6-(4-(carbazol-9-yl)phenyl)-2,4-diphenylnicotinonitrile (CzPN) and 2,4-diphenyl-6-(4- (1,3,6,8-tetramethyl-carbazol-9-yl)phenyl) nicotinonitrile (tMCzPN) were designed and synthesized accordingly. With the same and simple molecular framework, tMCzPN successfully exhibits TADF behavior, while CzPN is a non-TADF fluorophor, as the additional steric hindrance of methyl groups leads to a more twisted structure of tMCzPN. In the organic light-emitting diodes (OLEDs), tMCzPN exhibits extremely high forward-viewing maximum external quantum efficiency of 26.0%, without any light out-coupling enhancement, which is significantly higher than that of 5.3% for CzPN. These results indicate that tMCzPN is an excellent TADF emitter and proves that tMCz is a more appropriate candidate than Cz to develop TADF emitters.

12.
Chem Sci ; 11(3): 888-895, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-34123067

RESUMO

Rational manipulation of energy utilization from excited-state radiation of theranostic agents with a donor-acceptor structure is relatively unexplored. Herein, we present an effective strategy to tune the exciton dynamics of radiative excited state decay for augmenting two-photon nanotheranostics. As a proof of concept, two thermally activated delayed fluorescence (TADF) molecules with different electron-donating segments are engineered, which possess donor-acceptor structures and strong emissions in the deep-red region with aggregation-induced emission characteristics. Molecular simulations demonstrate that change of the electron-donating sections could effectively regulate the singlet-triplet energy gap and oscillator strength, which promises efficient energy flow. A two-photon laser with great permeability is used to excite TADF NPs to perform as theranostic agents with singlet oxygen generation and fluorescence imaging. These unique performances enable the proposed TADF emitters to exhibit tailored balances between two-photon singlet oxygen generation and fluorescence emission. This result demonstrates that TADF emitters can be rationally designed as superior candidates for nanotheranostic agents by the custom controlling exciton dynamics.

13.
Adv Sci (Weinh) ; 5(9): 1800436, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30250791

RESUMO

A novel thermally activated delayed fluorescence (TADF) emitter 12,15-di(10H-phenoxazin-10-yl)dibenzo[a,c]dipyrido[3,2-h:2',3'-j]phenazine (DPXZ-BPPZ) is developed for a highly efficient red organic light-emitting diode (OLED). With rigid and planar constituent groups and evident steric hindrance between electron-donor (D) and electron-acceptor (A) segments, DPXZ-BPPZ realizes extremely high rigidity to suppress the internal conversion process. Meanwhile, the highly twisted structure between D and A segments will also lead to an extremely small singlet-triplet energy split to DPXZ-BPPZ. Therefore, DPXZ-BPPZ successfully realizes an efficient fluorescent radiation transition and reverse intersystem crossing process, and possesses an extremely high photoluminescence quantum efficiency of 97.1 ± 1.1% under oxygen-free conditions. The OLED based on DPXZ-BPPZ shows red emission with a peak at 612 nm and a Commission Internationale de L'Eclairage (CIE) coordinate of (0.60, 0.40), and it achieves high maximum forward-viewing efficiencies of 20.1 ± 0.2% (external quantum efficiency), 30.2 ± 0.6 cd A-1 (current efficiency), and 30.9 ± 1.3 lm W-1 (power efficiency). The prepared OLED has the best performance among the reported red TADF OLEDs. These results prove that DPXZ-BPPZ is an ideal candidate for red TADF emitters, and the designing approach is valuable for highly efficient red TADF emitters.

14.
ACS Appl Mater Interfaces ; 9(10): 8848-8854, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-28218516

RESUMO

Thermally activated delayed fluorescence (TADF) emitters have attracted much interest for their great applications in organic light-emitting diodes (OLEDs), but the TADF OLEDs are limited by large efficiency roll-offs. In this study, we report two coumarin-based TADF emitters, 3-methyl-6-(10H-phenoxazin-10-yl)-1H-isochromen-1-one (PHzMCO) and 9-(10H-phenoxazin-10-yl)-6H-benzo[c]chromen-6-one (PHzBCO), with relatively high photoluminescence quantum yields (PLQYs) and extremely small singlet-triplet splittings. OLEDs using these two TADF compounds as the emitters respectively demonstrate high external quantum efficiencies of 17.8% for PHzMCO and 19.6% for PHzBCO, which are the highest among the reported coumarin-derivative-based OLEDs. More importantly, these devices based on PHzMCO and PHzBCO remained 10.3% and 12.9% at 10000 cd m-2, respectively, showing relatively low efficiency roll-offs at high brightness. These results reveal that the TADF emitters with high PLQYs can effectively reduce the efficiency roll-off in the devices.

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