Multiple resonance (MR) type thermally activated delayed fluorescence (TADF) material is currently a research hotspot in organic light‐emitting diodes (OLEDs) due to their high color purity and high ...exciton utilization. However, there are only a handful of MR‐TADF emitters with emissions beyond the blue‐to‐green region. The very limited emission colors for MR‐TADF emitters are mainly caused by the fact that so far molecular modifications of MR‐TADF do not offer much change in the emission colors. Here, we report a new approach to modifying a prototypical MR core of DABNA by fusing carbazoles to the MR framework. The carbazole‐fused molecule (TCZ‐F‐DABNA) basically maintains the MR‐dominated features of DABNA while red‐shifting the emission. Its OLED achieves an external quantum efficiency of 39.2 % with a peak at 588 nm, which is a record‐high efficiency for OLEDs with peaks beyond 560 nm. This work provides a new approach for significantly tunning emission colors of MR‐TADF emitters.
A new approach is reported by fusing carbazoles to a MR framework DABNA to significantly redshift emission while maintaining the MR‐dominated features. The carbazole‐fused molecule TCZ‐F‐DABNA can deliver a high PLQY of 99 %. Its OLEDs reached a record‐high EQE of 39.2 %.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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.
By introducing phenyl or o‐tolyl groups into different positions of the same acceptor backbone, the lowest triplet energy levels of red thermally activated delayed fluorescence emitters can be tuned from locally excited triplet (3LEA) to charge transfer triplet (3CT) states, resulting in enhancement of the rates of reverse intersystem crossing (RISC), and boosting efficiencies in both vacuum‐ and solution‐processed OLEDs.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
As crucial antigen presenting cells, dendritic cells (DCs) play a vital role in tumor immunotherapy. Taking into account the many recent advances in DC biology, we discuss how DCs (1) recognize ...pathogenic antigens with pattern recognition receptors through specific phagocytosis and through non-specific micropinocytosis, (2) process antigens into small peptides with proper sizes and sequences, and (3) present MHC-peptides to CD4
and CD8
T cells to initiate immune responses against invading microbes and aberrant host cells. During anti-tumor immune responses, DC-derived exosomes were discovered to participate in antigen presentation. T cell microvillar dynamics and TCR conformational changes were demonstrated upon DC antigen presentation. Caspase-11-driven hyperactive DCs were recently reported to convert effectors into memory T cells. DCs were also reported to crosstalk with NK cells. Additionally, DCs are the most important sentinel cells for immune surveillance in the tumor microenvironment. Alongside DC biology, we review the latest developments for DC-based tumor immunotherapy in preclinical studies and clinical trials. Personalized DC vaccine-induced T cell immunity, which targets tumor-specific antigens, has been demonstrated to be a promising form of tumor immunotherapy in patients with melanoma. Importantly, allogeneic-IgG-loaded and HLA-restricted neoantigen DC vaccines were discovered to have robust anti-tumor effects in mice. Our comprehensive review of DC biology and its role in tumor immunotherapy aids in the understanding of DCs as the mentors of T cells and as novel tumor immunotherapy cells with immense potential.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Critical patients with the coronavirus disease 2019 (COVID-19), even those whose nucleic acid test results had turned negative and those receiving maximal medical support, have been noted to progress ...to irreversible fatal respiratory failure. Lung transplantation (LT) as the sole therapy for end-stage pulmonary fibrosis related to acute respiratory distress syndrome has been considered as the ultimate rescue therapy for these patients.
From February 10 to March 10, 2020, three male patients were urgently assessed and listed for transplantation. After conducting a full ethical review and after obtaining assent from the family of the patients, we performed three LT procedures for COVID-19 patients with illness durations of more than one month and extremely high sequential organ failure assessment scores.
Two of the three recipients survived post-LT and started participating in a rehabilitation program. Pearls of the LT team collaboration and perioperative logistics were summarized and continually improved. The pathological results of the explanted lungs were concordant with the critical clinical manifestation, and provided insight towards better understanding of the disease. Government health affair systems, virology detection tools, and modern communication technology all play key roles towards the survival of the patients and their rehabilitation.
LT can be performed in end-stage patients with respiratory failure due to COVID-19-related pulmonary fibrosis. If confirmed positive-turned-negative virology status without organ dysfunction that could contraindicate LT, LT provided the final option for these patients to avoid certain death, with proper protection of transplant surgeons and medical staffs. By ensuring instant seamless care for both patients and medical teams, the goal of reducing the mortality rate and salvaging the lives of patients with COVID-19 can be attained.
While monochrome organic light‐emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters have achieved over 30% external quantum efficiencies (EQEs), all‐TADF white ...OLEDs (WOLEDs) are still lagging behind. Herein, a simple system based on two color‐complementary TADF emitters is exploited to realize high‐performance WOLEDs. By doping a high‐performance orange–red TADF fluorophor (BPPZ‐DPXZ) into a blue TADF host (DBFCz‐Trz), energy transfer, and triplet‐to‐singlet conversion in the host‐dopant system can be optimized to simultaneously achieve full exciton utilization and color balance. With this design, all‐TADF single‐emitting‐layer WOLEDs with a maximum EQE up to 32.8% are demonstrated. This high efficiency surpasses EQEs of reported WOLEDs based on both TADF as well as phosphorescence. It is expected that this finding can provide new insight for designing highly efficient all‐TADF WOLEDs.
All thermally activated delayed fluorescence (TADF) single‐emitting‐layer white organic light‐emitting diodes are developed by using a high‐efficiency orange–red TADF fluorophor doped in a blue TADF fluorophor. Singlet and triplet excitons in the devices can be well shared and captured in two emitters, resulting in state‐of‐the‐art performances with maximum external quantum efficiencies of over 30%.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Hindered by spectral broadening issues with redshifted emission, long‐wavelength (e.g., maxima beyond 570 nm) multiple resonance (MR) emitters with full width at half maxima (FWHMs) below 20 nm ...remain absent. Herein, by strategically embedding diverse boron (B)/nitrogen (N) atomic pairs into a polycyclic aromatic hydrocarbon (PAH) skeleton, we propose a hybrid pattern for the construction of a long‐wavelength narrowband MR emitter. The proof‐of‐concept emitter B4N6‐Me realized orange‐red emission with an extremely small FWHM of 19 nm (energy unit: 70 meV), representing the narrowest FWHM among all reported long‐wavelength MR emitters. Theoretical calculations revealed that the cooperation of the applied para B‐π‐N and para B‐π‐B/N‐π‐N patterns is complementary, which gives rise to both narrowband and redshift characteristics. The corresponding organic light‐emitting diode (OLED) employing B4N6‐Me achieved state‐of‐the‐art performance, e.g., a narrowband orange‐red emission with an FWHM of 27 nm (energy unit: 99 meV), an excellent maximum external quantum efficiency (EQE) of 35.8 %, and ultralow efficiency roll‐off (EQE of 28.4 % at 1000 cd m−2). This work provides new insights into the further molecular design and synthesis of long‐wavelength MR emitters.
A hybrid pattern strategy is proposed, and a proof‐of‐concept multiple resonance emitter containing four boron atoms and six nitrogen atoms, namely, B4N6‐Me, is designed. B4N6‐Me realizes narrowband orange‐red emission with an extremely narrow full width at half maximum of 19 nm (energy unit: 70 meV) and delivers state‐of‐the‐art device performance with a maximum external quantum efficiency of 35.8 %.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
With the climate constantly changing, plants suffer more frequently from various abiotic and biotic stresses. However, they have evolved biosynthetic machinery to survive in stressful environmental ...conditions. Flavonoids are involved in a variety of biological activities in plants, which can protect plants from different biotic (plant-parasitic nematodes, fungi and bacteria) and abiotic stresses (salt stress, drought stress, UV, higher and lower temperatures). Flavonoids contain several subgroups, including anthocyanidins, flavonols, flavones, flavanols, flavanones, chalcones, dihydrochalcones and dihydroflavonols, which are widely distributed in various plants. As the pathway of flavonoid biosynthesis has been well studied, many researchers have applied transgenic technologies in order to explore the molecular mechanism of genes associated with flavonoid biosynthesis; as such, many transgenic plants have shown a higher stress tolerance through the regulation of flavonoid content. In the present review, the classification, molecular structure and biological biosynthesis of flavonoids were summarized, and the roles of flavonoids under various forms of biotic and abiotic stress in plants were also included. In addition, the effect of applying genes associated with flavonoid biosynthesis on the enhancement of plant tolerance under various biotic and abiotic stresses was also discussed.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Building blocks and heteroatom alignments are two determining factors in designing multiple resonance (MR)‐type thermally activated delayed fluorescence (TADF) emitters. Carbazole‐fused MR emitters, ...represented by CzBN derivatives, and the heteroatom alignments of ν‐DABNA are two star series of MR‐TADF emitters that show impressive performances from the aspects of building blocks and heteroatom alignments, respectively. Herein, a novel CzBN analog, Π‐CzBN, featuring ν‐DABNA heteroatom alignment is developed via facile one‐shot lithium‐free borylation. Π‐CzBN exhibits superior photophysical properties with a photoluminescence quantum yield close to 100 % and narrowband sky blue emission with a full width at half maximum (FWHM) of 16 nm/85 meV. It also gives efficient TADF properties with a small singlet‐triplet energy offset of 40 meV and a fast reverse intersystem crossing rate of 2.9×105 s−1. The optimized OLED using Π‐CzBN as the emitter achieves an exceptional external quantum efficiency of 39.3 % with a low efficiency roll‐off of 20 % at 1000 cd m−2 and a narrowband emission at 495 nm with FWHM of 21 nm/106 meV, making it one of the best reported devices based on MR emitters with comprehensive performance.
Collocating carbazole building blocks with ν‐DABNA heteroatom alignment, a novel double boron‐embedded multiple resonance emitter Π‐CzBN is obtained and exhibits superior photophysical properties. The corresponding organic light‐emitting diodes based on Π‐CzBN achieve an exceptional efficiency of 39.3 % with a mild roll‐off and a narrow full width at half maximum of 21 nm/106 meV in the bluish‐green region.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Abstract
Deep‐red/near‐infrared (DR/NIR) organic light‐emitting diodes (OLEDs) are promising for applications such as night‐vision readable marking, bioimaging, and photodynamic therapy. To tune ...emission spectra into the DR/NIR region, red emitters generally require assistance from intermolecular interactions. But such interactions generally lead to sharp efficiency declines resulting from unwanted quenching events. To overcome this challenge, herein, an advanced method via strategically managing the intermolecular interactions of thermally activated delayed fluorescence (TADF) emitters is proposed. The proof‐of‐concept molecule called DCN‐SPTPA exhibits impressive resistance to quenching while delivering controllable aggregation behavior for redshifting the emission by installing an end‐spiro group. Consequently, two emitters demonstrate similar photophysical properties and device performance at very low doping levels; while
DCN‐SPTPA
‐based OLEDs demonstrate a 1.3–1.4‐fold enhancement of the external quantum efficiencies (EQEs) with respect to the control molecule at 5–20 wt.% doping ratios, affording DR/NIR emission at 656, 688, 696, and 716 nm with record‐breaking EQEs of 36.1%, 29.3%, 28.2%, and 24.0%, respectively. Moreover,
DCN‐SPTPA
‐based nondoped NIR device also retains a state‐of‐the‐art EQE of 2.61% peaked at 800 nm. This work first demonstrates instructive guidance for accurately manipulating the intermolecular interactions of red TADF emitters, which will spur future developments in high‐performance DR/NIR OLEDs.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In December 2019, a new type viral pneumonia cases occurred in Wuhan, Hubei Province; and then named "2019 novel coronavirus (2019-nCoV)" by the World Health Organization (WHO) on 12 January 2020. ...For it is a never been experienced respiratory disease before and with infection ability widely and quickly, it attracted the world's attention but without treatment and control manual. For the request from frontline clinicians and public health professionals of 2019-nCoV infected pneumonia management, an evidence-based guideline urgently needs to be developed. Therefore, we drafted this guideline according to the rapid advice guidelines methodology and general rules of WHO guideline development; we also added the first-hand management data of Zhongnan Hospital of Wuhan University. This guideline includes the guideline methodology, epidemiological characteristics, disease screening and population prevention, diagnosis, treatment and control (including traditional Chinese Medicine), nosocomial infection prevention and control, and disease nursing of the 2019-nCoV. Moreover, we also provide a whole process of a successful treatment case of the severe 2019-nCoV infected pneumonia and experience and lessons of hospital rescue for 2019-nCoV infections. This rapid advice guideline is suitable for the first frontline doctors and nurses, managers of hospitals and healthcare sections, community residents, public health persons, relevant researchers, and all person who are interested in the 2019-nCoV.
PDF
