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Simultaneously realizing improved carrier mobility and good photoluminescence (PL) efficiency in red thermally activated delayed-fluorescence (TADF) emitters remains challenging but important. Herein, two isomeric orange-red TADF emitters

Three multi-dentate coordinated chelates L

Rationally tuning the emission position and narrowing the full width at half-maximum (FWHM) of an emitter is of great importance for many applications. By synergistically improving rigidity, strengthening the resonant strength, inhibiting molecular bending and rocking, and destabilizing the HOMO energy level, a deep-blue emitter (CZ2CO) with a peak wavelength of 440 nm and an ultranarrow spectral FWHM of 16 nm (0.10 eV) was developed via intramolecular cyclization in a carbonyl/N resonant core (QAO). The dominant u0-0 transition character of CZ2CO gives a Commission Internationale de I'Éclairage coordinates (CIE) of (0.144, 0.042), nicely complying with the BT.2020 standard. Moreover, a hyper-fluorescent device based on CZ2CO shows a high maximum external quantum efficiency (EQEmax) of 25.6% and maintains an EQE of 22.4% at a practical brightness of 1000 cd m-2.

The development of photoinduced luminescent radicals with dynamic emission color is still challenging. Herein we report a novel molecular radical system (TBIQ) that shows photo-controllable luminescence, leading to a wide range of ratiometric color changes via light excitation. The conjugated skeleton of TBIQ is decorated with steric-demanding tertiary butyl groups that enable appropriate intermolecular interaction to make dynamic intermolecular coupling possible for controllable behaviors. We reveal that the helicenic pseudo-planar conformation of TBIQ experiences a planarization process after light excitation, leading to more compactly stacked supermolecules and thus generating radicals via intermolecular charge transfer. The photo-controllable luminescent radical system is employed for a high-level information encryption application. This study may offer unique insight into molecular dynamic motion for optical manufacturing and broaden the scope of smart-responsive materials for advanced applications.

Pt(ii) dicarbene pincer complexes served as a promising dopant sensitizer to an MR-TADF terminal emitter.

Resonance interaction between a molecular transition and a confined electromagnetic field can lead to weak or strong light-matter coupling. Considering the substantial exciton–phonon coupling in thermally activated delayed fluorescence (TADF) materials, it is thus interesting to explore whether weak light-matter coupling can be used to redistribute optical density of states and to change the rate of radiative decay. Here, we demonstrate that the emission distribution of TADF emitters can be reshaped and narrowed in a top-emitting organic light-emitting device (OLED) with a weakly coupled microcavity. The Purcell effect of weak microcavity is found to be different for TADF emitters with different molecular orientations. We demonstrate that radiative rates of the TADF emitters with vertical orientation can be substantial increased in weakly coupled organic microcavity. These observations can enhance external quantum efficiencies, reduce efficiency roll-off, and improve color-purities of TADF OLEDs, especially for emitters without highly horizontal orientation., This work not only presents photophysical processes of thermally activated delayed fluorescent emitters in a weak Fabry-Pérot cavity, but also establishes a connection between emitter orientation and Purcell effect.

Four blue-emissive iridium(III) complexes bearing a 3,3'-(1,3-phenylene)bis[1-isopropyl-6-(trifluoromethyl)-3

High efficiency and stable blue phosphors have been a persistent pursuit in the field of organic light-emitting diodes (OLEDs). Bis-tridentate Ir(III) complexes are considered as promising alternatives because of their excellent emission efficiency and good photostability. However, the emission colors of photostable bis-tridentate Ir(III) emitters reported so far do not reach the deep blue region. Herein, fluorene is introduced in the design of blue bis-tridentate Ir(III) complexes. By modifying a fluorene-based dianionic chelate with tert-butyl, methoxy, pyrrolidinyl and triazolyl appendages, five blue emitting bis-tridentate Ir(III) phosphors were successfully designed and prepared. Emissions of the new phosphors exhibited a gradual blue shift from the sky blue to the deep blue region according to the electron donating abilities of the added substituents. A deep blue OLED was successfully fabricated based on Flu-4 and presented an excellent maximum external quantum efficiency of 22.3% with CIE coordinates of (0.17, 0.19), which are comparable to the state-of-the-art deep blue phosphors.

Enhancing the reverse intersystem crossing (RISC) process of thermally activated delayed fluorescent (TADF) emitters is an effective approach to realize efficient organic light-emitting diodes (OLEDs) with low efficiency roll-off. In this work, we designed two novel TADF emitters, SAT-DAC and SATX-DAC, via a spiro architecture. Efficient maximum external quantum efficiencies (EQEs) of 22.6 and 20.9% with reduced efficiency roll-off (EQEs of 17.9 and 17.0% at 1000 cd m-2) were achieved via a "two-RISC-channel" strategy. X-ray diffraction shows close donor (D)/acceptor (A) spacing and suitable D/A orientation in crystals of the two emitters favoring both intra- and intermolecular through-space charge transfer (TSCT) processes. Transient photoluminescence decay measurements show that both emitters have two RISC channels leading to kISCT exceeding 106 s-1. These results suggest that the "two-RISC-channel" design can be a novel approach for enhancing performance of TADF emitters, in particular at high excitation densities.

In this work, we report a series of bis-tridentate Ir(III) metal complexes, comprising a dianionic pyrazole-pyridine-phenyl tridentate chelate and a monoanionic chelate bearing a peripheral carbene and carboline coordination fragment that is linked to the central phenyl group. All these Ir(III) complexes were synthesized with an efficient one-pot and two-step method, and their emission hue was fine-tuned by variation of the substituent at the central coordination entity (i.e., pyridinyl and phenyl group) of each of the tridentate chelates. Their photophysical and electrochemical properties, thermal stabilities and electroluminescence performances are examined and discussed comprehensively. The doped devices based on [Ir(cbF)(phyz1)] (Cb1) and [Ir(cbB)(phyz1)] (Cb4) give a maximum external quantum efficiency (current efficiency) of 16.6% (55.2 cd/A) and 13.9% (43.8 cd/A), respectively. The relatively high electroluminescence efficiencies indicate that bis-tridentate Ir(III) complexes are promising candidates for OLED applications.

Upon fusing the pyrazinyl pyrazole entity in giving pyrazolo[3,4- f ]quinoxaline chelate, the corresponding Os(II) based NIR emitter exhibited "invisible" and efficient electroluminescence with peak max. at 811 nm and a maximum external quantum efficiency of 0.97% and suppressed efficiency roll-off till a current density of 300 mA cm -2 .

To achieve high-efficiency deep-blue electroluminescence satisfying Rec.2020 standard blue gamut, two thermally activated delayed fluorescent (TADF) emitters are developed: 5-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)-10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasiline (TDBA-PAS) and 10-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)-9,9-diphenyl-9,10-dihydroacridine (TDBA-DPAC). Inheriting from their parented organoboron multi-resonance core, both emitters show very promising deep-blue emissions with relatively narrow full width at half-maximum (FWHM, ≈50 nm in solution), high photoluminescence quantum yield (up to 92.3%), and short emission lifetime (≤2.49 µs) with fast reverse intersystem crossing (10

Parasitic diseases have been widely epidemic in China with a long history. Great endeavours made in past 70 years led to significant decrease in morbidity and mortablity caused by several major parasitic diseases, while challenges existed to eliminate parasitic diseases. Surveillance-response system has play a crucial role in identifying public health problems, ascertaining the distribution and epidemic dynamics, discovering outbreaks and epidemic anomalies, evaluating the effects of on-site intervention activities and identifying risk factors. In this article, we reviewed the progress of the surveillance system for parasitic diseases, analysed the role of NIPD in the construction and application of surveillance-response system of parasitic diseases through elaborating the surveillance activities and typical surveillance-response events led by NIPD. Suggestion and comments for improve the surveillance-response system were put forward for further control or elimination of parasitic diseases.

A novel host material featuring a spiro-annulated benzimidazole configuration is exploited for blue phosphorescent organic light-emitting devices (PhOLEDs). The new material exhibits a high triplet energy (3.07 eV) and a bipolar characteristic and is effective as the host for FIrpic-, FIr6- and FK306-based blue PhOLEDs with high performances.

A series of six Ir(III)-based blue-emitting bis-tridentate phosphors, for which a 6-pyrazoly-2-phenoxypyridine (pzyPx) chelate is functionalized with either a m- or p-CF3 substituent at the terminal phenoxy site, and a tert-butyl substituent at the 4-position of the central pyridyl group, while the substituent of a carbene pincer ancillary is varied from methyl, isopropyl and to benzyl, are strategically designed and synthesized. A majority of these blue phosphors exhibit a nearly unitary emission quantum yield (Φ) in degassed solution and enhanced stability against photo-degradation in degassed toluene solution comparable to that of green, sky-blue and true-blue emitters, i.e. fac-[Ir(ppy)3], FIrpic and mer-[Ir(pmp)3], under irradiation with a xenon lamp at a power density of 620 W m−2 and at 35 °C. Corresponding OLED devices are fabricated using these pzyPx functionalized Ir(III) phosphors co-doped in a 9-(3-(9H-carbazol-9-yl)phenyl)-9H-carbazole-3-carbonitrile (mCPCN) host material, giving a max. EQE in the range of 8.0–12.2% and stable CIEx,y coordinates between (0.16, 0.22) and (0.17, 0.27). Importantly, the max. EQE of these OLEDs is qualitatively proportional to the phosphorescence radiative lifetime recorded in either the solution state or the doped host matrix, showing a critical factor for the development of successive blue emitters.

Simultaneously accomplishing a high efficiency and a slow efficiency roll-off at practical luminance levels remains challenging for thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs). In this study, for the first time, we reveal the new potential of an indandione unit featuring double carbonyl moieties, which is widely used in organic solar cells, as an electron-accepting core for constructing efficient TADF emitters. As a proof of concept, two TADF emitters, 5PXZ-PIDO and 5,6PXZ-PIDO, are developed by connecting an indandione (IDO) core with electron-donating phenoxazine (PXZ) units via phenylene π-bridges. Impressively, both emitters exhibit a distinct TADF nature with short DF lifetimes of ∼2 μs, and display relatively high photoluminescence quantum yields (ΦPLs) of over 70%. More importantly, a yellow OLED based on 5,6PXZ-PIDO achieves a high external quantum efficiency of 14.2% and an ultra-slow efficiency roll-off of 16.0% at a practical luminance of 1000 cd m−2, which is outstanding among previously reported carbonyl-based TADF emitters. This finding unlocks the huge potential of indandione-based molecules as TADF emitters for high-performance OLEDs.

Two novel D–σ–A host materials 11,11-bis(9-phenyl-9H-carbazol-3-yl)-11H-benzo[4,5]imidazo[1,2-a]indole (BII–BCz) and 4,4′-(11H-benzo[4,5]imidazo[1,2-a]indole-11,11-diyl)bis(N,N-diphenylaniline) (BII–TPA) are synthesized by using the sp3 carbon attached to a newly designed 11H-benzo[4,5]imidazo[1,2-a]indole building block to link two electron-donating groups. The resulting materials feature high triplet energy levels, good thermal properties and suitable photophysical properties as universal hosts for full-color phosphorescent organic light-emitting diodes (OLEDs). Both BII–BCz and BII–TPA reveal excellent performances in blue, green, yellow, orange and red phosphorescent OLEDs with the same device structure. The employment of the new D–σ–A materials as single hosts in white OLEDs with a simple device structure allows us to achieve state-of-the-art performances. A single-emissive-layer white device based on BII–BCz demonstrates the highest performance with an external quantum efficiency up to 28.2% at 1000 cd m−2. Furthermore, this device displays extremely stable emission spectra, with a ΔCIE of only (0.009, 0.005) from 1000 to 10 000 cd m−2.

In this work, we introduce an n-type group, TPPO (triphenyl phosphine), to the N1-position of violet-blue fluorophore phenanthroimidazole (PI) and successfully develop one deep-blue (TPAPOPPI) and two violet-blue emitters (3-CzPOPPI and CzBPOPPI) for OLEDs (organic light-emitting diodes). With a highly twisted linkage, the TPPO group shows negligible influences on their photophysical properties of the new materials and the materials inherit highly efficient deep-blue and violet-blue emission of the PI unit and its C2-connected arylamine skeletons. Meanwhile, the TPPO group can open a new channel to transport the electron. The electron injection and transport abilities of the developed emitters are enhanced. Non-doped devices using the 3-CzPOPPI and the CzBPOPPI emitters exhibit an EQEmax (external quantum efficiency) of 5.08% and 4.42% with CIE (Commission Internationale de l'Eclarage) coordinates of (0.156, 0.061) and (0.157, 0.071), respectively. Similar efficiencies and even deeper blue emissions (CIEy = 0.050 for 3-CzPOPPI and 0.044 for CzBPOPPI) were observed in OLEDs with these emitters doped with 4,4′-bis(N-carbazolyl)-1,1′-biphenyl. TPAPOPPI is demonstrated to be a multifunctional deep-blue emitter and presents impressive performances when serving as non-doped (EQEmax = 6.69%, CIE: (0.152, 0.095)), and doped (EQEmax = 6.61%, CIE: (0.154, 0.068)) as well as a high-performance host for yellow phosphorescent OLED. By doping a yellow phosphorescent dye (PO-01) into a TPAPOPPI host, a white OLED with a high EQE of 20.3% and a low driving voltage of 3.2 V (at 1000 cd m−2) is achieved.

To increase the fluorescence quantum yield of hybrid local and charge-transfer (HLCT) material, we introduce a symmetric linear D- π -A- π -D structure into molecular design and synthesized a new blue emitter, 2,2'-(2′,3′,5′,6'-tetrafluoro-[1,1':4′,1″-terphenyl]-4,4″-diyl)bis(1-(4-( tert -butyl)phenyl)-1 H -phenanthro[9,10- d ]imidazole) ( 4FBTPI ). Organic light-emitting devices employing 4FBTPI as a dopant emitter show good performances, with CIE (Commission Internationale de l’Enclairage) coordinates of (0.15, 0.09), which is very close to NTSC blue light standard (0.14, 0.08), current efficiencies (CE) of 6.03 cd A −1 , external quantum efficiencies of 6.94%. This performance is comparable to those of recently reported state-of-the-art deep-blue materials with CIE y

Three new anthracene-based emitters, 4-(10-(9,9′-spirobi[fluoren]-2-yl)anthracen-9-yl)benzonitrile (SBF-AnCN), 4-(10-(9,9-diphenyl-9H-fluoren-2-yl)anthracen-9-yl)benzonitrile (DPF-AnCN) and 4-(10-(9,9-dimethyl-9H-fluoren-2-yl)anthracen-9-yl)benzonitrile (DMF-AnCN) are developed for deep blue organic light-emitting diodes (OLEDs). Their photophysical properties, thermal properties, molecular configurations and device performances have been systematically investigated. As verified by crystallographic study, these anthracene derivatives possess highly twisted configuration, leading to deep-blue light emission by restraining π-conjugation extension. Furthermore, the difference in the molecular packing manner may influence the photoluminescence quantum yields (PLQYs) in solid state and the proportion of singlet exciton harvested by triplet–triplet annihilation (TTA) process. A nondoped device fabricated using DPF-AnCN as emitter exhibits a maximum external quantum efficiency (EQE) of 7.1% with insignificant efficiency roll-off (6.6%@1000 nit) and Commission Internationale de L’Eclairage (CIE) index of (0.149, 0.104), approaching the standard blue index of the National Television System Committee (NTSC) of (0.14, 0.08). It is demonstrated that TTA is responsible for the excellent electroluminescence (EL) performance. In comparison with doped OLEDs, transient EL decay measurements demonstrate that TTA process is more efficient in the nondoped device. This work would provide an efficient method for designing deep-blue nondoped EL materials.

Novel bis-tridentate Ir(III) complexes are of great interest in the development of blue-emitting organic light-emitting diodes (OLEDs) due to their rigid and robust molecular architecture. In this work, both the functional 6-pyrazolyl-2-phenoxypyridine (pzyPx) and 6-(1,2,4-triazolyl)-2-phenoxypyridine (tazPx) were used as chromophoric chelates in the construction of the blue-emitting Ir(III) phosphors. Accordingly, the substitution of pzyPx with tazPx chelates retains the desired characteristics, i.e. both high quantum yields (>92%) in solution and shortened radiative lifetime (τrad) (from 19.8 to 2.5 μs), respectively. The theoretical calculation reveals that the triazolate moiety contributes considerably to the radiative transition, to which the greater iridium involvement in T1 → S0 transition of tazPx-based complex is responsible for the shortened τrad. Consequently, enhanced photostabilities in degassed toluene and competitive performances with maximum EQE of 19.2% with CIE coordinates of (0.17, 0.22) were observed from the tazPx-based complex Px-33.

Objective: To study the correlation of serum CysC content with oxidative stress and renal interstitial fibrosis in patients with diabetic nephropathy. Methods: Patients with type 2 diabetes mellitus who were treated in Yangxin People's Hospital between May 2013 and February 2017 were selected as the research subjects, and according to the urinary albumin / creatinine ratio (UACR), they were divided into the simple type 2 diabetes mellitus group (T2DM group) with UACR＜30 mg/g·Cr, microalbuminuria group (MA group) with UACR 30-300 mg/g·Cr and macroalbuminuria group (LA group) UACR＞300 mg/g·Cr. The contents of CysC and oxidative stress indicators in serum as well as the contents of renal interstitial fibrosis indicators in urine were detected. Results: Serum CysC, NOX4 and MDA contents as well as urine Col-IV, FN, TGF-β and CTGF contents in MA group and LA group were significantly higher than those in T2DM group while HO-1, SOD and GSH-Px contents were significantly lower than those in T2DM group; serum CysC, NOX4 and MDA contents as well as urine Col-IV, FN, TGF-β and CTGF contents in LA group were significantly higher than those in MA group while HO-1, SOD and GSH-Px contents were significantly lower than those in MA group; serum NOX4 and MDA contents as well as urine Col-IV, FN, TGF-β and CTGF contents in diabetic nephropathy patients with high CysC were significantly higher than those in diabetic nephropathy patients with normal CysC while HO-1, SOD and GSH- Px contents were significantly lower than those in diabetic nephropathy patients with normal CysC. Conclusion: The increase of serum CysC content in patients with diabetic nephropathy is closely related to the activation of oxidative stress response and renal interstitial fibrosis.

Organic materials containing arylamines have been widely used as hole-transporting materials as well as emitters in organic light-emitting devices (OLEDs). However, it has been pointed out that the C-N bonds in these arylamines can easily suffer from degradation in excited states, especially in deep-blue OLEDs. In this work, phenanthro[9,10-d]imidazole (PI) is proposed as a potential donor with higher stability than those of arylamines. Using PI as the donor, a donor-acceptor type deep-blue fluorophore 1-phenyl-2-(4″-(1-phenyl-1H-benzo[d]imidazol-2-yl)-[1,1':4',1″-terphenyl]-4-yl)-1H-phenanthro[9,10-d]imidazole (BITPI) is designed and synthesized. Results from UV-aging test on neat films of BITPI and other three arylamine compounds demonstrate that PI is indeed a more stable donor comparing to common arylamines. An OLED using BITPI as an emitter exhibits good device performances (EQE over 7%) with stable deep-blue emission (color index: (0.15, 0.13)) and longer operation lifetime than the similarly structured device using arylamine-based emitter. Single-organic layer device based on BITPI also shows superior performances, which are comparable to the best results from the arylamine-based donor-acceptor emitters, suggesting that PI is a stable donor with good hole transport/injection capability.

Construction of donor–acceptor (D–A) molecules with a highly hybridized local and charge-transfer (HLCT) excited state has been shown to be an effective strategy to achieve the maximum electroluminescence (EL) efficiency through the synchronous harvest of high photoluminescence (PL) efficiency and exciton utilization. Herein, two novel D–A-structured bifunctional (emissive and hole-transporting) materials, PPI-2TPA and PPI-2NPA, have been designed and synthesized for application in deep-blue OLEDs. As revealed by theoretical calculations and comprehensive photophysical experiments, both of them exhibit significant HLCT excited-state characteristics and ambipolar properties. Using them as emitting layers (EML) in multilayer non-doped devices presents true deep-blue Commission Internationale de l’Eclairage (CIE) coordinates of ca. (0.15, 0.06), accompanied by record-setting performance with maximum external quantum efficiencies (EQEs) of 7.20% for PPI-2TPA and 6.33% for PPI-2NPA. Remarkably, the simple bilayer devices fabricated using them as non-dopant EML and hole-transporting layers (HTLs) still deliver EQEs as high as 4.69% and 4.10% with little changes in color purity (PPI-2TPA: CIE (0.150, 0.063) and PPI-2NPA: (0.152, 0.063)). To the best of our knowledge, this performance is the highest among the reported non-doped devices in this color gamut, irrespective of whether the two newly formed molecules functioned as EML or EML and HTL simultaneously.

By using molecular twisting and bulky side group substitution, we successfully develop two deep-blue emitters, BiPI-1 and BiPI-2 . These two twisted linear molecules retain the excellent photophysical and electrical properties of planar analogue and remarkably supress redshifts in solid state emission. Especially, BiPI-1 showed deep-blue emission in both solution and solid phase, and high carrier mobilities with μ h > 10 −3 cm 2 V −1 s −1 and μ e > 10 −5 cm 2 V −1 s −1 . Standard blue electroluminescence (color purity: (0.15, 0.08)) and high device efficiency (CE: 4.62 cd A −1 , EQE: 6.18%) were observed in a non-doped OLED of BiPI-1 .

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.

To reveal the relationship between the microstructural morphologies, tensile behaviors, and strain hardening mechanism of Cr-Mn-Si-Ni alloyed ultra-strength steel, uniaxial tensile tests of a Cr-Mn-Si-Ni alloyed steel were conducted at room temperature (RT) and elevated temperatures with different strain rates in this study. When the tensile test was carried out at RT, increased strain rate led to increased dislocation density of the tensed Cr-Mn-Si-Ni alloyed steel specimen and resulted in increased value of yield strength. Because the dislocation entanglement and strain hardening of tensed Cr-Mn-Si-Ni alloyed steel were inhibited by increased strain rate, decreased value of ultimate strength was measured. During tensile test at RT, the dislocations rearranged and transformed to low-angle grain boundaries and high-angle grain boundaries sequentially. Above microstructural evolution resulted in microstructural refinement of Cr-Mn-Si-Ni alloyed steel. The strain hardening of Cr-Mn-Si-Ni alloyed steel during tensile test at RT was divided into four stages according to the calculated values of strain hardening rate. The microstructural evolution behaviors including accumulation of dislocations, generation and transformation of slips took place in different stages of strain hardening were affected significantly by the strain rate. Based on the true stress-true strain curves, the effects of the tensile temperature and strain rate on the values of the yield strain, fracture strain, yield strength, and ultimate strength of Cr-Mn-Si-Ni alloyed steel tensed under different experimental conditions were studied. A two-stage constitutive model of Cr-Mn-Si-Ni alloyed steel associated with dislocation density was established based on the experimental results.

Fluorescent organic nanoparticles based on small molecules have been regarded as promising candidates for bioimaging in recent years. In this study, we report a highly stable near-infrared (NIR) fluorescent organic nanoprobes based on nanoparticles of an anthraquinone derivate with strong aggregation-induced emission (AIE) characteristics and a large Stokes shift (175 nm). These endow the nanoprobe with high fluorescent brightness and high signal-to-noise ratio. On the other hand, the nanoprobe also shows low cytotoxicity, good stability over a wide pH range, superior resistance against photodegradation and photobleaching comparing to typical commercial fluorescent organic dyes such as fluorescein sodium. Endowed with such merits in term of optical performance, biocompatibility, and stability, the nanoprobe is demonstrated to be an ideal fluorescent probe for noninvasive long-term cellular tracing and imaging applications. As an example, it is shown that strong red fluorescence from the nanoprobe can still be clearly observed in A549 human lung cancer cells after incubation for six generations over 15 days.

We report a series of novel phenanthroimidazole (PI) based bipolar deep blue-emitting compounds. The structure-property relationship is systematically studied. A star-shape steric group tetraphenylbenzene (TPB) is substituted to the C2 position of PI, which contributes to high-efficiency deep blue photoluminescence (PL) in solid state; while electron-withdrawing or donating groups are attached to the N1 position to realized tunable charge transfer character for high exciton utilization. Among all the emitters, the non-doped electroluminescent devices based on TPBPPI-PY and TPBPPI-PBI display superior EQE of 5.70% and 5.94% with color coordinates of (0.16, 0.049) and (0.16, 0.059), respectively. These performances are among the best deep blue OLEDs with CIEy

Sky-blue and blue-emitting, carbazolyl functionalized, bis-tridentate Ir(III) phosphors Cz-1-Cz-3 with bright emission and short radiative lifetime are successfully synthesized in a one-pot manner. They exhibit very high photostability against UV-vis irradiation in degassed toluene, versus both green and true-blue-emitting reference compounds, i.e., fac-[Ir(ppy)3] and mer-[Ir(pmp)3]. Organic light-emitting diodes (OLEDs) based on Cz-2 exhibit maximum external quantum efficiency (EQE) of 21.6%, EQE of 15.1% at 100 cd m-2, and with CIE x,y coordinates of (0.17, 0.25). This study provides a conceptual solution to the exceedingly stable and efficient blue phosphor. It is promising that long lifespan blue OLED based on these emitters can be attained with further engineering of devices suitable for commercial application.

A new ternary acceptor (A)-donor (D)-acceptor (A) asymmetrically twisted deep-blue emitting molecule, PPI-2BI, was synthesized by attaching two electrophilic benzimidazole (BI) units to the C2 and N1 positions of a phenanthroimidazole (PI) donor unit. Profiting from the enhanced D-A electronic coupling, the electron injecting and transporting abilities of the new triangle-shaped A-D-A molecule are considerably improved and the molecule shows high photoluminescence (PL) and electroluminescence (EL) efficiencies. By using PPI-2BI as a non-doped emitting layer (EML), the resulting organic light-emitting device exhibits emission with color coordinates of (0.158, 0.124) and a maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 4.63 %, 4.98 cd A-1 , and 4.82 lm W-1 , respectively. Additionally, a simple bilayer device using PPI-2BI as both the EML and the electron-transporting layer (ETL) also shows an EQE of 3.81 % with little changes to the color purity. Remarkably, a PPI-2BI-based doped device emits efficient near-ultraviolet EL with color coordinates of (0.154, 0.047) and an EQE of 4.12 %, which is comparable to that of the best reported near-UV emitting devices.

Hamiltonian matrices have many applications to design automation and autocontrol, in particular in the linear-quadratic autocontrol problem. This paper studies the inverse problems of generalized Hamiltonian matrices for matrix equations. By real representation of complex matrix, we give the necessary and sufficient conditions for the existence of a Hermitian generalized Hamiltonian solutions to the matrix equations, and then derive the representation of the general solutions.

The behaviors of the SO 2 oxidative adsorption and the reduction decomposition of formed sulfate over Mg–Fe–Al–O mixed spinel catalyst were studied by in situ IR, MR–GC–MS, Mossbauer spectroscopy and electrical conductivity measurement techniques. In the oxidative adsorption and/or reaction process, SO 2 and oxygen molecules are adsorbed on the lattice oxygen ions and oxygen vacancies, respectively. During the SO 2 adsorption and reaction, adsorbed sulfur species react with the lattice oxygen ions and form the sulfite-like species. When oxygen molecules are present in the feed mixture, sulfate is formed from the sulfite-like species reacting with the adsorbed oxygen ions. When the sulfated samples are reduced by hydrogen at 773 K, a large amount of H 2 S along with a small part of SO 2 is produced. Different iron species, Fe 3+ , Fe 2.5+ , Fe 2+ and Fe 0 are identified in the sulfated sample during the reduction process. In the half cycle of SO 2 oxidative adsorption and reaction, iron ions are directly involved in the formation of the mixed sulfate; in the half cycle of the reduction, due to the S–O–Fe bond being easily broken, the reducibility of the mixed sulfate hence is improved. A mechanism on the cycle between SO 2 oxidative adsorption and sulfate reductive decomposition is proposed.