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Minisci reaction of heteroarenes and unactivated C(sp3)–H alkanes via a photogenerated chlorine radical from FeCl3 and seawater.

A simple and inherent green photocatalytic approach using commercially available and cheap nBu4NBr with 4-CzIPN was reported to effectively initiate the site-selective α-C(sp3)-H activation of tetrahydrofuran for C-S and C-C cross-couplings.

A simple and transition-metal-free HFIP-induced allylation reaction of tertiary allylic alcohols with thiols or sulfonyl hydrazine derivatives was reported for the efficient and highly selective synthesis of allylic sulfides and allylic sulfones. Herein, HFIP played a vital role in not only activating the allylic alcohol, but also stabilizing the allylic cation intermediate to accelerate the subsequent transformations.

Comparison of the nanostructured Si photocathodes fabricated by chemical etching (c-Si), electrochemical etching (ec-Si) and photoelectrochemical etching (pec-Si) and their dramatically enhanced PEC water splitting.

A photoredox approach was reported to realize a highly selective three-component thiohydroxylation, thioalkoxylation and thioamination of vinylarenes towards valuable vicinal S,O- and S,N-disubstituted molecules under mild conditions.

We developed two D–A–D′ type red materials with “hot exciton” feature. Experimental results proved that the choice of an electron transport group as D′ was important to improve charge transfer balance and realize high brightness.

This work demonstrated a regulable cross-coupling of alcohols with benzothiazole under visible light. Two kinds of products, alkyl- and acetyl-derived benzothiazoles, are achieved with high yields up to 99% in Ar and 90% in air, respectively.

A simple and mild photoredox catalytic approach to access difluoroalkylated dioxodibenzothiazepines in high regioselectivity via radical cascade cyclization has been described herein. In contrast to previous methods, this strategy does not involve the use of transition-metal catalysts and avoids the potential disadvantages of inevitable toxicity and the tedious removal process of metal catalysts. The commercially available and inexpensive CF2 precursors, wide substrate scope, and mild reaction conditions demonstrate the practicability of this approach.

Acquiring desirable device performance with deep-blue color purity that fulfills practical application requirements is still a challenge. Bipolar fluorescent emitters with hybrid local and charge transfer (HLCT) state may serve to address this issue. Herein, by inserting anthracene core in the deep-blue building blocks, the authors successfully developed two highly twisted D-π-A fluorescent emitters, ICz-An-PPI and IP-An-PPI, featuring different acceptor groups. Both exhibited superb thermal stabilities, high photo luminescent quantum yields and excellent bipolar transport capabilities. The non-doped OLEDs using ICz-An-PPI and IP-An-PPI as the emitting layers showed efficient blue emission with an external quantum efficiency (EQEmax ) of 4.32 % and 5.41 %, and the CIE coordinates of (0.147, 0.180) and (0.149, 0.150), respectively. In addition, the deep blue doped device based on ICz-An-PPI was achieved with an excellent CEmax of 5.83 cd A-1 , EQEmax of 4.6 % and the CIE coordinate of (0.148, 0.078), which is extremely close to the National Television Standards Committee (NTSC) standard. Particularly, IP-An-PPI-based doped device had better performance, with an EQEmax of 7.51 % and the CIE coordinate of (0.150, 0.118), which was very impressive among the recently reported deep-blue OLEDs with the CIEy

Since the water oxidation half-reaction requires the transfer of multi-electrons and the formation of O-O bond, it's crucial to investigate the catalytic behaviours of semiconductor photoanodes. In this work, a bio-inspired copper-bipyridine catalyst of Cu(dcbpy) is decorated on the nanoporous Si photoanode (black Si, b-Si). Under AM1.5G illumination, the b-Si/Cu(dcbpy) photoanode exhibits a high photocurrent density of 6.31 mA cm

In contrast with the well-developed radical thiol-ene reaction to access anti-Markovnikov-type products, the research on the catalytic Markovnikov-selective hydrothiolation of alkenes is very restricted. Because of the catalyst poisoning of metal catalysts by organosulfur compounds, limited examples of transition-metal-catalyzed thiol-ene reactions have been reported. However, in this work, a directing-group-assisted hydrothiolation of styrenes with thiols by photoredox/cobalt catalysis is found to proceed smoothly to afford Markovnikov-type sulfides with excellent regioselectivity.

High-performance deep-blue emitters with external quantum efficiencies (EQEs) exceeding 5 % are still scarce in organic light-emitting diodes (OLEDs). In this work, by introducing a [1,2,4]triazolo[1,5-a] pyridine (TP) unit at the N1 position of phenanthroimidazole (PI), two luminescent materials, PTPTPA and PTPTPA, were obtained. Systematic photophysical analysis showed that the TP block is suitable for constructing hybridized local and charge-transfer (HLCT) emitters. Its moderate electron-withdrawing ability and rigid planar structure can enhance the CT component while ensuring color purity. In addition, compared with PTPTPA, the additional phenyl ring of PTPBPTA not only increased the oscillator strength, but also decreased the Stokes shift. TDDFT calculations pointed out facile reverse intersystem crossing processes in PTPTPA from high-lying triplet states to the singlet excited state. A nondoped device based on PTPTPA as emitter showed impressive performance with EQEmax of 7.11 % and CIE coordinates of (0.15, 0.09). At the same time, it was also an efficient host for yellow and red phosphorescent OLEDs. By doping yellow (PPYBA) and red (BTPG) phosphorescent dyes into PTPTPA, a white OLED with a high EQE of 23.85 % was achieved. The successful design of PTPTPA not only provided an optimization choice for OLED emitters, but also demonstrated the empirical rules for the design of multifunctional deep-blue emitters.

By utilizing the bipolarity of 1,2-diphenylphenanthroimidazole (PPI), two types of asymmetrical tripartite triads (PPI-TPA and PPI-PCz) were designed with triphenylamine (TPA) and 9-phenylcarbazole (PCz). These triads are deep-blue luminescent materials with a high fluorescence quantum yield of nearly 100 %. To trace the photophysical behaviors of these triads, their excited-state evolution channels and interchromophoric interactions were investigated by ultrafast time-resolved transient absorption and excited-state theoretical calculations. The results suggest that the electronic nature, asymmetrical tripartite structure, and electron-hole distance of these triads, as well as solvent polarity, determine the lifetime of intramolecular charge transfer (ICT). Interestingly, PPI-PCz triads show anti-Kasha ICT, and the charge-transfer direction among the triads is adjustable. For the PPI-TPA triad, the electron is transferred from TPA to PPI, whereas for the PPI-PCz triad the electron is pushed from PPI to PCz. Exploration of the excited-state ICT in these triads may pave the way to design better luminescent materials in the future.

Two non-ionic hydro-fluorocarbon hybrid surfactants with and without hydroxyl groups were synthesized and compared. They exhibited good thermal stability and superior surface activity. It was observed that the hydroxyl group had a profound effect on modifying the surface tension of their solutions and the morphology of the formed micelles. This effect may be attributed to the rearranging of the alkane group from above the air/aqueous surface to below it and the disrupting of the interfacial water structure induced by the hydroxyl groups. This work provides a strategy to weaken the immiscibility between hydrocarbon and fluorocarbon chains by modifying their orientational structure at the interface, thus it is helpful for the design of surfactants with varied interfacial properties.

Dopamine (DA) is an important neurotransmitter associated with nerve signaling and some diseases. Therefore, it is very significant to detect DA in patients to regulate body function. Compared with...

In this work, four phenanthroimidazole (PI) based isomers TPA-PPI-PBI, TPA-PPI-NPBI, PBI-PPI-TPA and NPBI-PPI-TPA for high-efficiency deep-blue organic light-emitting diodes (OLEDs) have been designed and synthesized. The structure–property relationship is systematically studied. Devices based on TPA-PPI-PBI, TPA-PPI-NPBI, PBI-PPI-TPA and NPBI-PPI-TPA achieved deep-blue emissions with Commission Internationale de L'Eclairage (CIE) coordinates of (0.15, 0.07), (0.15, 0.07), (0.15, 0.09) and (0.15, 0.05) and high external quantum efficiencies (EQEmax) of 4.12%, 4.66%, 6.88% and 5.59%, respectively. The PBI-PPI-TPA based device exhibited negligible efficiency roll-off with an EQE of 6.48% at practical 1000 cd m−2. Moreover, the EQE is still above 5% even at a high brightness of 10 000 cd m−2. Comparing the four isomers, we found that the substituent at the C2 position of the PI core has a significant influence on the emission wavelength and CIE coordinates. This work provides a rational design strategy where modifying an electron acceptor (A) at the C2 position and an electron donor (D) at the N1 position of the PI core will be an effective way to fabricate high-performance PI-based bipolar emitters.

Phosphorescent and thermally activated delayed fluorescence (TADF) emitters can break through the spin statistics rules and achieve great success in external quantum efficiency (over 5%). However, maintaining high efficiency at high brightness is a tremendous challenge for applications of organic light emitting diodes. Hence, we reported two phenanthroimidazole derivatives PPI-An-CN and PPI-An-TP and achieved extremely low efficiency roll-off with about 99% of the maximum external quantum efficiency (EQEmax) maintained even at a high luminance of 1000 cd/cm2 based non-doped devices. When doping the two materials in CBP (4,4′-bis(N-carbazolyl)-1,1′-biphenyl), the doped devices still exhibited excellent stability at high brightness with CIEy ≈ 0.07 and low turn-on voltage of only 2.8 V. The state-of-the-art low efficiency roll-off makes the new materials attractive for potential applications. It is the first time that the Fragment Contribution Analysis method has been used to analyze the excited state properties of the molecules in the field of OLEDs, which helps us understand the mechanism more intuitively and deeply.

A light-promoted and tertiary-amine-assisted strategy for efficient hydroxysulfenylation of both electron-rich and electron-deficient alkenes with thiophenols to selectively and directly access β-hydroxysulfides in one pot is described herein. In contrast to the previously reported thiol-oxygen co-oxidation reactions, this simple and sustainable approach features mild reaction conditions, high efficiency, and excellent functional group tolerance.

Herein, we reported a dual-catalytic platform for the allylation of amines and sulfonyl hydrazines with olefins to selectively access α-allylic amines and allylic sulfones in good yields by combining photoredox catalysis and cobaloxime catalysis. This strategy avoided the use of a stoichiometric amount of terminal oxidant and the use of pre-functionalized allylic precursors, representing a green and ideal atom- & step-economical process. Good substrate scope and gram-scale synthesis demonstrated the utility of this protocol. Mechanistic studies revealed that a radical process is probably involved in this reaction.

Developing an effective method for the detection of aflatoxin B1 (AFB1) remains an arduous task due to the high toxicity of AFB1 to a health concern. In this study, a sensitive and reliable electrochemical aptasensor based on carbon dots/α-Fe

Bipolar blue or deep-blue emitting materials are particularly effective to achieve high-performance full color OLEDs. In this study, a novel deep-blue bipolar fluorophore, PPI-F-Cz was designed and synthesized by attaching an electron-withdrawing chromophore phenanthro[9,10-d] imidazole (PI) and an electron-donating group carbazole to the sp3-hybridized C9 atom of the fluorene. Profiting from balanced carrier mobility, the molecule shows high photoluminescence (PL) and electroluminescence (EL) efficiencies. Using PPI-F-Cz as a non-doped emitting layer (EML), an organic light-emitting device exhibits high performance with CIE color coordinates of (0.155, 0.055), a maximum external quantum efficiency (EQE) of 4.64%, current efficiency (CE) of 7.68 cd/A, and power efficiency (PE) of 8.04 lm/W. Additionally, equipped with the bipolar transport properties and high triplet energy (2.40 eV), PPI-F-Cz was allowed to be used as an efficient host for green and red PhOLEDs with the maximum EQEs of 16.83% and 20.98%, CEmax of 58.47 cd/A and 25.19 cd/A, PEmax of 53.66 lm/W and 23.28 lm/W respectively.

Deep blue emitters with good stability, high quantum yield, high triplet energy, and good carrier transporting properties are crucial for full color display and white solid lighting. To solve this, We designed, synthesized and characterized two bipolar deep-blue emitters 2-(4-(9,9′-spirobi[fluoren]-2-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d]imidazole (2-PPI SBF) and 2-(4-(9,9′-spirobi[fluoren]-4-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d]imidazole (4-PPI SBF). Both the materials show good stability, high quantum yield and high triplet energy. Equipped with their bipolar properties, 2-PPI SBF and 4-PPI SBF based non-doped devices show impressive performance with maximum external quantum efficiency (EQE) of 4.78% and 5.29% along with desirable color purity of CIE color coordinates of (0.154, 0.105) and (0.155, 0.058) respectively. Interestingly, the high triplet energy allows them to be used as a host for PhOLEDs. High performance green PhOLEDs based on 4-PPI SBF show the maximum EQE, CE and PE of 16.79%, 64.09 cd/A and 67.92 l m/W respectively. And, high performance red PhOLEDs based on 2-PPI SBF and 4-PPI SBF were also achieved with the maximum EQE of 13.07% and 14.83%, respectively. Furthermore, 4-PPI SBF-based WOLED shows high efficiencies with EQEmax of 12.27%, CEmax of 27.78 cd/A and PEmax of 32.68 l m/W. An efficient white OLED with CIE coordinates of (0.367, 0.305) which is slightly deviated from the values of the theoretical white point (0.33, 0.33) was obtained.

A simple, mild and efficient approach to access fluorinated dibenz[b,e]azepines via visible-light photoredox catalysis is presented. Inexpensive and commercially available fluoroalkyl anhydrides in concert with pyridine N-oxide are employed as the source of the fluoroalkyl radicals. A one-pot process involving the trifluoroacetylation of unprotected secondary benzyl amines followed by radical cyclization could also afford the desired fluorinated dibenz[b,e]azepines.

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

Developing an effective method for the detection of aflatoxin B1 (AFB1) remains an arduous task due to the high toxicity of AFB1 to a health concern. In this study, a sensitive and reliable electrochemical aptasensor based on carbon dots/α-Fe2O3-Fe3O4 nanocomposite (CDs/α-Fe2O3-Fe3O4) is constructed for the determination of AFB1. The CDs have good electrical conductivity and large specific surface areas to improve the aptasensor’s sensitivity. The α-Fe2O3-Fe3O4 can not only improve the catalytic performance of the aptasensor but also have magnetism, which can realize the recovery of CDs/α-Fe2O3-Fe3O4 to avoid material waste and environmental pollution. This electrochemical aptasensor can achieve a good linear (0.001–100.0 nM) and excellent detection limit (0.5 pM) for the determination of AFB1. In addition, the aptasensor was also applied to determine AFB1 in beer, rice, and peanuts, all results were in good agreement with HPLC, indicating that the electrochemical aptasensor has a broad application prospect.

A photoredox/cobaloxime co-catalyzed coupling reaction of α-ketoacids and methacrylates to obtain allylic ketones is described. Without the cobaloxime catalyst, 1,4-dicarbonyl compounds are generated. The cobaloxime catalyst enables dehydrogenation to generate the formation of new olefins. The generality, good substrate scope and mild conditions are good features in the photoredox/cobaloxime catalysis protocol, and this method will provide new opportunities for the functionalization of more olefins.

Two novel bipolar deep-blue fluorescent emitters, IP-PPI and IP-DPPI, featuring different lengths of the phenyl bridge, were designed and synthesized, in which imidazo[1,2-a]pyridine (IP) and phenanthroimidazole (PI) were proposed as an electron acceptor and an electron donor, respectively. Both of them exhibit outstanding thermal stability and high emission quantum yields. All the devices based on these two materials showed negligible efficiency roll-off with increasing current density. Impressively, non-doped organic light-emitting diodes (OLEDs) based on IP-PPI and IP-DPPI exhibited external quantum efficiencies (EQEs) of 4.85 % and 4.74 % with CIE coordinates of (0.153, 0.097) and (0.154, 0.114) at 10000 cd m-2 , respectively. In addition, the 40 wt % IP-PPI doped device maintained a high EQE of 5.23 % with CIE coordinates of (0.154, 0.077) at 10000 cd m-2 . The doped device based on 20 wt % IP-DPPI exhibited a higher deep-blue electroluminescence (EL) performance with a maximum EQE of up to 6.13 % at CIE of (0.153, 0.078) and maintained an EQE of 5.07 % at 10000 cd m-2 . To the best of our knowledge, these performances are among the state-of-the art devices with CIEy ≤0.08 at a high brightness of 10000 cd m-2 . Furthermore, by doping a red phosphorescent dye Ir(MDQ)2 (MDQ=2-methyldibenzo[f,h]quinoxaline) into the IP-PPI and IP-DPPI hosts, high-performance red phosphorescent OLEDs with EQEs of 20.8 % and 19.1 % were achieved, respectively. This work may provide a new approach for designing highly efficient deep-blue emitters with negligible roll-off for OLED applications.

A new fluorescent probe T2 for Zn2+, by employing coumarin and quinoline as the detection platform, was rationally designed and synthesized. Of particular significance was that T2 showed a specific colorimetric and ratiometric response towards Zn2+ without interference from other biologically important cations. T2 also displayed high affinity towards Zn2+ ions with a Kd of 0.98 μM with a visually detectable color change from yellow to pale red in absorption, and from green to yellow in emission. The detection limit for Zn2+ was estimated at 48.1 nM, which was below the threshold limit value of Zn2+ in drinking water (46 μM) according to World Health Organization. Moreover, the probe T2 displayed low cytotoxicity and good cell membrane permeability at physiological temperature. The imaging of Zn2+ in living cells and the quantitative determination of Zn2+ levels in the real water samples were successfully demonstrated. This study developed a new receptor toward Zn2+ for the further study on the qualitative and quantitative determination of Zn2+ in the biological system.

A novel diphenylimidazole derivative (PTN), which shows strong excimer emission, has been designed and utilized in organic solar cells (OSCs). The extended solid-state excimer emission facilitates intra-system self-absorption and accelerates photon trapping in OSCs. The ternary OSC based on PTB7-Th:PTN:PC71BM using a green solvent (ethylbenzene) exhibits a high PCE of 11.44%, which is 28.40% higher than that of the binary device (8.91%). The great enhancement is mainly ascribed to the increased self-absorption in the system. Furthermore, the well-organized stacking of PTN is beneficial to promote overlap between small molecules and polymers and then accelerates intermolecular energy transfer. The most important thing to note is that ternary OSCs fabricated both with halogen and nonhalogen solvents show better air, thermal and light irradiation stability, compared with the control device. Over 55 days of air storage, the PCE of the unpackaged ternary OSC still remains at 76%, whereas the control device becomes inefficient. The performance is among the best results for both efficiency and stability in PTB7-Th:PC71BM based solar cells, which can narrow the gap between laboratory investigations and industrial production.

Multifunctional materials are crucial and have promising applications in a wide range of organic electronics. Herein, we designed and synthesized two bipolar blue molecules named 2-(4-(4,5-diphenyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazol-1-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d]imidazole (PPI-PIM-TPE) and 1-phenyl-2-(4-(2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-phenanthro[9,10-d]imidazol-1-yl)phenyl)-1H-phenanthro[9,10-d]imidazole (2PPI-TPE) with aggregation-induced emission (AIE) and mechanochromism characteristics. They both have good thermal stability (Td is 505 °C for PPI-PIM-TPE and 510 °C for 2PPI-TPE), strong AIE properties and reversible mechanochromism. The quantum yields in the solid state were as high as 61.9% for PPI-PIM-TPE and 73.4% for 2PPI-TPE. In addition, the two pristine solid powders are white and emit blue light. After grinding, the solid becomes yellow and emits blue-green emission. The color changes are reversible by solvent fuming. The change in emission color can be observed by the naked eye, demonstrating that they are typical mechanochromic materials. Non-doped blue OLEDs based on 2PPI-TPE exhibit an external quantum efficiency (EQE), current efficiency (CE) and power efficiency (PE) of 2.48%, 6.46 cd A−1 and 4.72 lm W−1, respectively. The doped device based on 2PPI-TPE as a dopant emitter exhibits a higher EQE, CE and PE of 3.55%, 6.67 cd A−1 and 5.52 lm W−1. The performances of the OLEDs with these emitters are among the best of recent reports based on blue materials with AIE and mechanochromism simultaneously.

Two efficient fluorescence molecules, named 1-(4-trifluoromethylphenyl)-2-(4′-(1,4,5-triphenyl-1H-imidazole-2-yl)-[1,1′-biphenyl]-4-yl)-1H-phenanthro[9,10- d ]imidazole ( PPI-PIM-1 ) and 1-(4-trifluoromethylphenyl)-2-(4′-(2,4,5-triphenyl-1H-imidazole-1-yl)-[1,1′-biphenyl]-4-yl)-1H-phenanthro[9,10- d ]imidazole ( PPI-PIM-2 ) were designed and synthesized, in which the electron-withdrawing trifluoromethyl group was introduced firstly to N1-position benzene of phenanthroimidazole to improve the electron transporting ability and tune the charge transfer (CT) component. In addition, compared to biphenanthroimidazole derivatives, here, we break one rigid plane of phenanthroimidazole to inhibit aggregation-induced-quenching (ACQ) and change the position from C1 to N1 to restrict the conjugation length simultaneously. The devices based on PPI-PIM-1 and PPI-PIM-2 exhibited stable deep-blue emission with CIE coordinates of (0.15, 0.08) and (0.15, 0.07) and achieved maximum external quantum efficiencies of 4.3% and 4.5% respectively. More importantly, the corresponding exciton utilization efficiencies are as high as 27.0% and 30.3%.

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

There is an increasing demand to solve the environmental dissemination problems of fluorosurfactants and improve their responsive behavior, surface properties, chemical stability and foaming performance. In this work, three pH-responsive fluorosurfactants, named F9-es-mor, F9-N3-mor and F9-N2-mor, were synthesized by facile one-step esterification or amidation. The F9-N2-mor efficiently reduced the water surface tension to 14.56 mN·m−1 with a low critical micelle concentration (CMC) of 0.20 mM. More importantly, both F9-N2-mor and F9-N3-mor obviously displayed reproducible pH-response foaming behaviors at an optimal pH of 6.0 and 8.0, respectively, probably owing to their rigid molecular structure, strong intermolecular H-bond and high membrane elasticity. Besides, the morpholine fluorosurfactants defoam at pH below 4.0, indicating that these fluorosurfactants could be recycled and their residue could be easily removed. Overall, the novel fluorosurfactants F9-N2-mor might provide new inspiration to recycle fluorosurfactants as well as construct pH-responsive foams.

Two series of novel gemini surfactants with morpholinium headgroup and benzene-based rigid spacers (abbreviated as (Mor)m-P-m and (Mor)m-BP-m, where m represents the carbon numbers of hydrophobic chains) were synthesized and characterized by 1H NMR, ESI-MS, and FT-IR spectra. The effect of lengths of rigid spacer and hydrocarbon chain on their solution properties and antibacterial activities were systematically investigated. Due to the existence of morpholinium, they have a superior surface activity to the classic gemini surfactants. (Mor)m-BP-m possess lower CMC and γcmc than (Mor)m-P-m, which is assumed to be related to the conformation change of spacer. The possible arrangement models for the adsorptions of (Mor)m-P-m and (Mor)m-BP-m at the air-water interface were proposed by comparing their surface parameters with those of other similar surfactants. The pre-micellar associations occur in aqueous solutions of (Mor)16-P-16, (Mor)14-BP-14 and (Mor)16-BP-16. The thermodynamic parameters indicate the micellar processes are spontaneous, and (Mor)m-BP-m have stronger aggregation tendency than (Mor)m-P-m. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) show they spontaneously self-assemble into vesicle, and the aggregate size of (Mor)m-BP-m is larger than (Mor)m-P-m. These surfactants showed excellent antibacterial properties against Bacillus subtilis and Escherichia coli. Compared with (Mor)m-P-m, (Mor)m-BP-m exhibit a higher activity.

Of paramount significance in phosphorescent organic light‐emitting diodes (PHOLEDs) are the facts that Förster resonance energy transfer (FRET) must be sufficient and back energy transfer should be prohibited. Herein, the FRET efficiencies for high‐performance PHOLEDs based on a simple bipolar luminogen 1‐phenyl‐2‐(5′‐phenyl‐[1,1′:3′,1″‐terphenyl]‐4‐yl)‐1H‐phenanthro[9,10‐d]imidazole (PHT‐PPI) with high triplet energy of 2.44 eV are systematically investigated. As a result, with PO‐01 as dopant, the high‐performance orange PHOLED is achieved with maximum external quantum efficiency (EQEmax) of 26.14% and ultrahigh brightness of 152 000 cd m−2, which are the highest reported efficiencies for orange OLEDs with such high brightness. In addition, the green and red PHOLEDs are also fabricated with EQEmax of 15.38% and 16.12%, respectively. Furthermore, the nondoped device based on PHT‐PPI as a deep‐blue emitter is also obtained with an EQEmax of 5.12% and the Commission Internationale de L’Eclairage (CIE) index of (0.15, 0.08). More importantly, the blue, green, orange, and red devices exhibit low efficiency roll‐off, particularly, of which the orange PHOLED is extremely small (

In this study, a green and fast method was developed to synthesize high-yield carbon dots (CDs) via one-pot microwave treatment of banana peels without using any other surface passivation agents. Then the as-prepared CDs was used as the reducing agent and stabilizer to synthesize a Pd-Au@CDs nanocomposite by a simple sequential reduction strategy. Finally, Pd-Au@CDs nanocomposite modified glassy carbon electrode (Pd-Au@CDs/GCE) was obtained as a biosensor for target DNA after being immobilized a single-stranded probe DNA by a carboxyl ammonia condensation reaction. Under the optimal conditions, the sensor could detect target DNA concentrations in the range from 5.0×10-16 to 1.0×10-1°molL-1. The detection limit (LD) was estimated to be 1.82×10-17molL-1, which showed higher sensitivity than other electrochemical biosensors reported. In addition, the DNA sensor was also successfully applied to detect colitoxin DNA in human serum.

In this study, a series of aromatically substituted phenanthro[9,10-d]imidazole (PI) fluorophores at C6 and C9 (no. 6 and 9 carbon atoms) have been synthesized and systematically characterized by theoretical, thermal, photophysical, electrochemical, and electroluminescent (EL) studies. C6 and C9 modifications have positive influences on the thermal properties of the new materials. Theoretical calculations suggest that the C6 and the C9 positions of PI are electronically different. Theoretical and experimental evidences of intramolecular charge transfer (ICT) between two identical moieties attaching to the C6 and the C9 positions are observed. Photophysical properties of the fluorophores are greatly influenced by size and conjugation extent of the substituents as well as linking steric hindrance. It is found that the C6 and C9 positions afford moderate conjugated extension compared to the C2 modification. Moreover, ICT characteristics of the new fluorophores increase as the size of the substituted aromatic group, and are partially influenced by steric hindrance, with the anthracene and the pyrene derivatives having the strongest ICT excited properties. EL performances of the fluorophores were evaluated as host emitters or dopants in organic light-emitting devices (OLEDs). Most of the devices showed significantly improved efficiencies compared to the OLED using the nonmodified emitter. Among all the devices, a 5 wt % TPI-Py doped device exhibited excellent performances with an external quantum efficiency5% at 1000 cd/m

A novel near ultraviolet (NUV) emitter, PIBCz, was designed and synthesized by attaching C3-position of the weak electron-donating N-phenylcarbazole group to C6- and C9-positions of phenanthroimidazole (PI) unit for limiting the molecular conjugation and intramolecular charge transfer (ICT) process. The new emitter exhibits strong NUV emission both in solution and thin film as well as good thermal and morphological stability. The PIBCz-based non-doped device shows a perfect color purity of CIE (0.15, 0.05), a very low turn-on voltage of 2.7 V and a maximum external quantum efficiency (EQE), current efficiency (CE) and power efficiency (PE) of 2.74%, 1.28 cd A−1 and 1.12 lm W−1, respectively, which is comparable to state-of-the-art non-doped OLEDs in similar color gamut. This work demonstrates that effective management of ICT process is a valuable strategy to develop high efficiency NUV emitters.