Pure Green Research Articles

Pure Green Ag–In–Ga–S/Ga–S Quantum Dot Light‐Emitting Diodes with Electron Transport Materials Exhibiting Enhanced Luminescence Properties

AbstractQuantum dots (QDs) are essential luminescent materials with applications in wide‐color‐gamut displays requiring exceptional color reproducibility. Multinary semiconductor QDs composed of groups I, III and VI elements are expected to serve as eco‐friendly materials to replace conventional QDs owing to the potential narrow spectral widths and tunable bandgaps of the former. Although optimized Ag–In–Ga–S/Ga–S core/shell QDs (AIGS QDs) have exhibited vibrant green emissions, electroluminescence from QD‐based light‐emitting diodes (QLEDs) incorporating these AIGS QDs is reduced as a consequence of the effects of defect sites. The present work therefore examines the incorporation of electron transport materials (ETMs) into AIGS QD emitting layers. A device incorporating emitting layers composed of AIGS QDs and 2,4,6‐tris(3‐(3‐pyridyl)phenyl)‐1,3,5‐triazine (TmPPyTz), with the latter acting as a highly conductive ETM, exhibits a low driving voltage and high efficiency. Furthermore, the addition of two ETMs — TmPPyTz and tris(2,4,6‐trimethyl‐3‐(pyridin‐3‐yl)phenyl)borane — is found to provide enhanced luminescence properties because these materials are deposited in the emitting layer in different forms and hence has varying effects in terms of improving conductivity and charge balance. The resulting QLEDs have a sharp spectral width of 30 nm, suggesting a level of color purity suitable for wide‐color‐gamut displays.

Peripherally Heavy‐Atom‐Decorated Strategy Towards High‐Performance Pure Green Electroluminescence with External Quantum Efficiency over 40 %

AbstractHeavy‐atom integration into thermally activated delayed fluorescence (TADF) molecule could significantly promote the reverse intersystem crossing (RISC) process. However, simultaneously achieving high efficiency, small roll‐off, narrowband emission and good operational lifetime remains a big challenge for the corresponding organic light‐emitting diodes (OLEDs). Herein, we report a pure green multi‐resonance TADF molecule BN‐STO by introducing a peripheral heavy atom selenium onto the parent BN‐Cz molecule. The organic light‐emitting diode device based on BN‐STO exhibited state‐of‐the‐art performance with a maximum external quantum efficiency (EQE) of 40.1 %, power efficiency (PE) of 176.9 lm W−1, well‐suppressed efficiency roll‐off and pure green gamut. This work reveals a feasible strategy to reach a balance between fast RISC process and narrow full width at half maximum (FWHM) of MR‐TADF by heavy atom effect.

Peripherally Heavy-Atom-Decorated Strategy Towards High-Performance Pure Green Electroluminescence with External Quantum Efficiency over 40 .

Heavy-atom integration into thermally activated delayed fluorescence (TADF) molecule could significantly promote the reverse intersystem crossing (RISC) process. However, simultaneously achieving high efficiency, small roll-off, narrowband emission and good operational lifetime remains a big challenge for the corresponding organic light-emitting diodes (OLEDs). Herein, we report a pure green multi-resonance TADF molecule BN-STO by introducing a peripheral heavy atom selenium onto the parent BN-Cz molecule. The organic light-emitting diode device based on BN-STO exhibited state-of-the-art performance with a maximum external quantum efficiency (EQE) of 40.1 %, power efficiency (PE) of 176.9 lm W-1 , well-suppressed efficiency roll-off and pure green gamut. This work reveals a feasible strategy to reach a balance between fast RISC process and narrow full width at half maximum (FWHM) of MR-TADF by heavy atom effect.

Metal-Perturbed Multiresonance TADF Emitter Enables High-Efficiency and Ultralow Efficiency Roll-Off Nonsensitized OLEDs with Pure Green Gamut.

Multiresonance (MR)-induced thermally activated delayed fluorescence (TADF) emitters based on B- and N-embedded polycyclic aromatics are desirable for ultrahigh-definition organic light-emitting diodes (OLEDs) due to their high photoluminescence quantum yield (PLQY) and narrow bandwidth. But the reverse intersystem crossing (RISC) rates of MR-TADF emitters are usually small, resulting in severe device efficiency roll-off at high brightness. To solve this issue, a sensitizer for the MR-TADF emitter has been required. Herein, a new MR-TADF emitter is developed through coordination of Au with B/N-embedded polycyclic ligand. Benefitting from the Au perturbation, the RISC rate is dramatically accelerated to 2.3 × 107 s-1 , leading to delayed fluorescence lifetime as short as 4.3 µs. Meanwhile, the PLQY of 95% and full width at half maximum of 39nm (0.18eV) are essentially unchanged after metal coordination. Therefore, a high PLQY, short delayed fluorescence lifetime, and high color purity are concurrently realized in a single TADF emitter. Accordingly, vacuum-deposited OLEDs exhibit high-performance electroluminescence with a maximum external quantum efficiency (EQE) of 35.8% without sensitization. The EQE is maintained as high as 32.3% at 10000cd m-2 . Furthermore, solution-processed OLED based on the emitter also achieves excellent performance with a maximum EQE of 25.7% and a small efficiency roll-off.

Development of Pure Green Thermally Activated Delayed Fluorescence Material by Cyano Substitution.

Multiple resonance (MR)-effect-induced thermally activated delayed fluorescence (TADF) materials have garnered significant attention because they can achieve both high color purity and high external quantum efficiency (EQE). However, the reported green-emitting MR-TADF materials exhibit broader emission compared to those of blue-emitting ones and suffer from severe efficiency roll-off due to insufficient rate constants of reverse intersystem crossing process (kRISC ). Herein, a pure green MR-TADF material (ν-DABNA-CN-Me) with high kRISC of 105 s-1 is reported. The key to success is introduction of cyano groups into a blue-emitting MR-TADF material (ν-DABNA), which causes remarkable bathochromic shift without a loss of color purity. The organic light-emitting diode employing it as an emitter exhibits green emission at 504nm with a small full-width at half-maximum of 23nm, corresponding to Commission Internationale d'Éclairage coordinates of (0.13, 0.65). The device achieves a high maximum EQE of 31.9% and successfully suppresses the efficiency roll-off at a high luminance.

Generation of Pure Green Up-Conversion Luminescence in Er3+ Doped and Yb3+-Er3+ Co-Doped YVO4 Nanomaterials under 785 and 975 nm Excitation.

Materials that generate pure, single-color emission are desirable in the development and manufacturing of modern optoelectronic devices. This work shows the possibility of generating pure, green up-conversion luminescence upon the excitation of Er3+-doped nanomaterials with a 785 nm NIR laser. The up-converting inorganic nanoluminophores YVO4: Er3+ and YVO4: Yb3+ and Er3+ were obtained using a hydrothermal method and subsequent calcination. The synthesized vanadate nanomaterials had a tetragonal structure and crystallized in the form of nearly spherical nanoparticles. Up-conversion emission spectra of the nanomaterials were measured using laser light sources with λex = 785 and 975 nm. Importantly, under the influence of the mentioned laser irradiation, the as-prepared samples exhibited bright green up-conversion luminescence that was visible to the naked eye. Depending on the dopant ions used and the selected excitation wavelengths, two (green) or three (green and red) bands originating from erbium ions appeared in the emission spectra. In this way, by changing the UC mechanisms, pure green luminescence of the material can be obtained. The proposed strategy, in combination with various single-doped UC nanomaterials activated with Er3+, might be beneficial for modern optoelectronics, such as light-emitting diodes with a rich color gamut for back-light display applications.

Quasi-Two-Dimensional Perovskite Nanosheets Based on the Triplet Energy Acceptor Molecule with Pure Green Emission Light

Quasi-two-dimensional hybrid perovskites have proved to be promising next-generation semiconductor materials for light-emitting diodes and photovoltaic applications. However, these materials usually contain a mixture of phases that their photoluminescence is not monochrome. Here, we synthesize a series of quasi-two-dimensional organic–inorganic hybrid perovskite nanosheets (NSs) with the triplet energy acceptor molecule naphthalene methylamine (NMA), that is, (NMA)2(MA)⟨n⟩–1Pb⟨n⟩Br3⟨n⟩+1 (NMA = C11H9NH3, ⟨n⟩ = 2,3,4). It was found that with the organic layer, the light color of the NSs is pure green on account of energy transfer from the inorganic layer whose band gap is beyond triplet states of NMA (∼2.6 eV). Also, we demonstrated that the triplet energy transfer lifetime is ∼7 ps for the ⟨n⟩ = 2 and ∼9 ps for the ⟨n⟩ = 3 quasi-two-dimensional hybrid perovskite NSs by spectroscopy.

KESEDIAAN MEMBAYAR LEBIH TERHADAP BERAS ORGANIK DI TRANSMART ICONMALL GRESIK

Public awareness of a healthy lifestyle makes organic products in great demand, including organic rice. The willingness to pay consumers for a good or service is determined by the desire of each individual or household who tries to maximize is utility with certain income and will determine the amount of demand for goods or services to be consumed. Therefore, it is necessary to do research on the factors that affect the willingness to pay consumers for organic rice. The research was conducted at Iconmall Gresik Transmart. The sample of this research was 40 people with the criteria that they had bought at least once organic rice products and were at least 17 years old. The data used in this research include primary data and secondary data. Data analysis used is contingent valuation analysis. The results showed that organic rice consumers are willing to pay more for all types of organic rice brands sold on Iconmall Gresik Transmart, where the total average for the type of Hotel Beras Kepala Super brand is Rp 33.214,286, Pure Green Pandan Wangi is Rp 41.444,445, Hotel Beras Merah Premium is Rp 36.181,817, dan Tropicana Slim Panino is Rp 39.096,001. DOI : https://doi.org/10.33005/adv.v9i2.2460

Solution-Processable Pure Green Thermally Activated Delayed Fluorescence Emitter Based on the Multiple Resonance Effect.

Thermally activated delayed fluorescence (TADF) materials based on the multiple resonance (MR) effect are applied in organic light-emitting diodes (OLEDs), combining high color purity and efficiency. However, they are not fabricated via solution-processing, which is an economical approach toward the mass production of OLED displays. Here, a solution-processable MR-TADF material (OAB-ABP-1), with an extended π-skeleton and bulky substituents, is designed. OAB-ABP-1 is synthesized from commercially available starting materials via a four-step process involving one-shot double borylation. OAB-ABP-1 presents attractive photophysical properties, a narrow emission band, a high photoluminescence quantum yield, a small energy gap between S1 and T1 , and low activation energy for reverse intersystem crossing. These properties are attributed to the alternating localization of the highest occupied and lowest unoccupied molecular orbitals induced by the boron, nitrogen, and oxygen atoms. Furthermore, to facilitate charge recombination, two novel semiconducting polymers with similar ionization potentials to that of OAB-ABP-1 are synthesized for use as interlayer and emissive layer materials. A solution-processed OLED device is fabricated using OAB-ABP-1 and the aforementioned polymers; it exhibits pure green electroluminescence with a small full-width at half-maximum and a high external quantum efficiency with minimum efficiency roll-off.

Achieving Pure Green Electroluminescence with CIEy of 0.69 and EQE of 28.2% from an Aza-Fused Multi-Resonance Emitter.

Pure green emitters are essential for realizing an ultrawide color gamut in next-generation displays. Herein, by fusing the difficult-to-access aza-aromatics onto B (boron)-N (nitrogen) skeleton, a hybridized multi-resonance and charge transfer (HMCT) molecule AZA-BN was successfully synthesized through an effective one-shot multiple cyclization method. AZA-BN shows pure green fluorescence with photoluminance quantum yield of 99.7 %. The corresponding green device exhibits a maximum external quantum efficiency and power efficiency of 28.2 % and 121.7 lm W-1 , respectively, with a full width half maximum (FWHM) of merely 30 nm and Commission Internationale de l'Eclairage (CIE) coordinate y of 0.69, representing the purest green bottom-emitting organic light-emitting diode.

Achieving Pure Green Electroluminescence with CIEy of 0.69 and EQE of 28.2% from an Aza‐Fused Multi‐Resonance Emitter

AbstractPure green emitters are essential for realizing an ultrawide color gamut in next‐generation displays. Herein, by fusing the difficult‐to‐access aza‐aromatics onto B (boron)–N (nitrogen) skeleton, a hybridized multi‐resonance and charge transfer (HMCT) molecule AZA‐BN was successfully synthesized through an effective one‐shot multiple cyclization method. AZA‐BN shows pure green fluorescence with photoluminance quantum yield of 99.7 %. The corresponding green device exhibits a maximum external quantum efficiency and power efficiency of 28.2 % and 121.7 lm W−1, respectively, with a full width half maximum (FWHM) of merely 30 nm and Commission Internationale de l'Eclairage (CIE) coordinateyof 0.69, representing the purest green bottom‐emitting organic light‐emitting diode.

Fast Synthesis of Iridium(III) Complexes Incorporating a Bis(diphenylphorothioyl)amide Ligand for Efficient Pure Green OLEDs.

Bis(diphenylphorothioyl)amide (Stpip) containing phosphor-sulfur (P═S) bonds was used as an ancillary ligand for three pure green iridium(III) emitters Ir1, Ir2, and Ir3, which were synthesized in few minutes at room temperature with high reaction yields above 70%. All these complexes show good thermal stability and excellent sublimation yields of around 80-90%, which are considered beneficial for industry practical production and organic light-emitting diode (OLED) fabrication. The emission profiles of these complexes meet the green standards of CIE1931 with coordinates of (0.33, 0.63), (0.33, 0.62), and (0.34, 0.62), respectively, and high photoluminescence quantum yields of up to 98% are achieved. Utilizing these complexes as emissive dopants, these OLEDs exhibited high current efficiency up to 91.94 cd A-1, external quantum efficiency up to 26.52%, and power efficiency up to 92.60 lm W-1 with very small efficiency roll-off, without adopting internal or external out-coupling methods. These results indicate that Stpip is a potentially suitable ligand scaffold for highly efficient phosphorescent Ir(III) emitters that endow corresponding OLEDs with high efficiency and small roll-off.

Phenolic profiling of complex tea samples via simultaneous multiplexed detection employing reaction flow HPLC columns and colorimetric post column derivatisation

A novel approach for the analysis of phenolics in tea was developed using multiplexed simultaneous detection. This is the first study employing a short reaction flow (RF) chromatography column (length 50mm) for the analysis of phenolics in complex samples (not a standard mixture of compounds). RF separation efficiency was high as the detectors are multiplexed simultaneously, rather than sequentially. The delay time between RF detection responses is minor (1.2s) providing simple peak assignment between the phenolic detection and conventional detectors, such as the UV and fluorescence detectors (FLD).Thirty-nine phenolics were detected amongst the five different tea samples (three from Camellia sinensis and two herbal teas). The highest number of phenols detected was 24 for English Breakfast tea (four highly abundant), 19 for Earl Grey (six highly abundant), 13 in Pure Green (two highly abundant) and 9 in both Fruit of the Forest (two highly abundant) and Camomile (none highly abundant) herbal teas. Numerous low concentration phenolic compounds in the Fruit of the Forest tea were not included due to their abundance being only slightly above the noise level of the detection process. The relative response factor (RRF) analysed at 520 and 500nm aided to identify unique phenolics to each sample with similar retention times; three phenolics were unique to the Pure Green tea (2.30, 4.11 and 5.80min) and two to the Earl Grey Tea (4.11 and 5.80min). The Fruit of the Forest tea and the Camomile tea were both distinctly different from all other teas. This approach may be used for phenolic profiling of food, beverages or natural products.

Eletroactive Properties of Pure and Malachite Green Doped PVK Samples

Eletroactive Properties of Pure and Malachite Green Doped PVK Samples

Effects of Various LED Light Colors on Growth and Immune Response in Broilers.

We evaluated the effects of different light-emitting diode (LED) colors between blue and green on growth performance and the immune response in broilers. A total of 1,200 1-day-old Ross broilers were divided randomly into six groups and exposed to pure blue (PB), bright blue (BB), sky blue (SB), greenish blue (GB), pure green (PG), or white (W) using LEDs for 6 weeks. Consequently, body weights were higher in chickens reared under PB and GB on day (d) 7 and SB on d 21 than the other groups. Chickens in the PB group on d 42 were the heaviest among the groups, followed by the BB group and were significantly heavier than the W group. Splenocyte proliferation was significantly enhanced in chickens reared under PB followed by BB on d 42 and proliferation of peripheral blood mononuclear cells was significantly enhanced in chickens reared under BB on d 42. In addition, chickens in the BB group showed significantly elevated nitric oxide production on d 42, indicating activation of macrophages. These results suggest that immune function and growth of broilers can be improved at the later stage by rearing under shorter wavelength LEDs such as PB and BB.

Effect of two different commercially available tea products on salivary pH: A randomized double blinded concurrent parallel study

Background: Many studies have demonstrated the beneficial effect of tea on dental caries. Aim: The aim of the present study was to compare and evaluate the effect of green tea and black tea infusions on salivary pH in caries free and with caries individuals. Settings and Design: Randomized double-blinded concurrent parallel study. Materials and Methods: Forty healthy subjects, aged 18-20 years participated in the study. Commercially available green tea (Tetley Pure Green Tea) and black tea (Tetley Black Tea) were used in the study. The pH of saliva and of the tested tea products was determined with a digital pH meter. pH of whole saliva was measured at baseline and immediately after the intake of product (0), 5, and 10 min later. Data analysis was carried out by Student's t-test and repeated measure ANOVA. Results: In vitro pH determination of infusion showed pH value of green tea (6.27 ± 0.02) was higher compared to black tea (6.13 ± 0.03). Both green and black tea infusion intake led to a statistically significant rise in salivary pH, both in caries-free and with caries groups, which remained above the base salivary pH over the whole period of measurements. Conclusion: The present study demonstrated that after intake of both green and black tea there was an increase in salivary pH both in caries-free and with caries groups. The pH rise was more in green tea intake compared to black tea.

秋末苏南茶园昆虫的群落组成及其趋色性

There are many top-quality,prestigious teas cultivated and processed in the Southern Jiangshu Province,China;however,serious damages to tea plants caused by various pests occur frequently in the region.In order to better understand the insect community structures and their phototaxis,we tested 12 colors(pure white,peach red,dark green,apple green,lake blue,sky blue,jasmine yellow,bud green,earth yellow,orange,bright red and purple) of sticky plates in a non-pollution tea plantation at Danyang City during late fall in 2012.The trapping results showed that: 1) within the 4 days trapping period,in total of 30455 individuals of 85 insect species belonged to 7 orders were caught,with Homoptera(86.5% of total individuals) being the most dominant order group,followed by Hymenoptera(8.8%) and Diptera(2.5%);2) the tea aphid and the tea green leafhopper were the two most dominant pest insect species,accounting for 71.5% and 15% of the total individuals,respectively;3) the Chinese honey bees were the major beneficial insects captured,accounting for 8.2% of the total individuals;4) in addition,a total of 1034 individuals of other beneficial insects(natural enemies) were caught,including 582 green lacewings(e.g.Chrysopa sinica Tjedea,Chrysopa septempunctata Wesmeal and Chrysopa formosa Branar),111 tachinids(Exorista civilis Rondani,Crossocosmia zebina Walk,Exorista sorbillans Wiedemann,plus three other species),110 hoverflies(Sphaerophoria menthastri L.,Syrphus balteatus De Geer,Syrphus corolla F.,Paraqus guadifasciatus Meigen,Syrphus serarius Wiedemann,Leucopis puncticornis Meigen plus two other species),97 braconids with Apanteles spp.being the dominant species,40 ichneumons(Itoplectis naranyae(Ashmead),Gotra octocinctus(Ashmead) and other three species) and 32 ladybeetles with Leis axyridis(Pallas) and Coelophora saucia Mulsant being the major species.5) Bud green,jasmine yellow and orange sticky plates captured significantly higher numbers of the tea green leafhoppers and the tea aphids;bud green and jasmine yellow sticky plates were also strongly attractive to ichneumons and braconids;bud green,earth yellow and apple green sticky plates attracted lacewings;apple green,sky blue and purple sticky plates trapped many flies and mosquitoes.The numbers of insect species captured were highest on the Jasmine yellow sticky plates,whereas the highest diversity index of various groups of trapped insects was detected on the pure white plates,indicating its broad generic attraction to diverse groups of insects.In late fall,knowing the species richness and the abundance of overwintering pest and beneficial insects,the beneficial/pest ratios,and the dominant pest and beneficial insect species and their population levels,as well as their differential phototaxis behaviors would help tea farmers better preparing and executing their environmentally safe pest control measures for efficiently reducing overwintering pest population density,before the field season is over.

Discrepancies between descriptions and illustrations of colours in Congo red-stained amyloid, and explanation of discrepant colours

Congo red-stained sections of amyloid may show various colours between crossed polariser and analyser. The aims were to see how papers described the colours, to compare descriptions with illustrations, and to explain the colours. In 160 papers on Congo red-stained amyloid, the commonest descriptions were ‘green birefringence’ and ‘apple-green birefringence’. In 191 figures in 82 papers, 59 (31%) showed a pure green colour, 62 (32%) showed green and yellow or blue and yellow, 38 (20%) showed green and a colour other than yellow, mostly red, and 32 (17%) showed other colours. Discrepancies between colours reported and illustrated were noted in 127 figures (66%). Most (77) were between green alone in descriptions and green and another colour in figures, and 30 were between green in descriptions and no green at all in figures. Pure green can be seen in ideal conditions, but more often there are green and yellow, explained by strain birefringence, and green and red or other combinations, explained by uncrossing of polariser and analyser. These other anomalous colours are just as characteristic of amyloid as the pure green colour. Many papers on Congo red-stained amyloid appear to describe what is expected theoretically rather than what is actually seen.

A New Polymeric Light‐Emitting Material with Pure Green Emission: Poly(fluorene‐alt‐quinoxaline) with Benzothiadiazole Groups in the Side Chain

AbstractA new alternative copolymer composed of fluorene and quinoxaline units having benzothiadiazole groups in the side chain was prepared and used as a green emitter for polymeric light‐emitting diodes to give a device emitting pure green color at about 520 nm with a chromaticity coordinate of (x = 0.32, y = 0.59), matching the NTSC 1979 standard green color (x = 0.31, y = 0.595) very well.magnified image

Design and Fabrication of Pure Green Color Microcavity Organic Light Emitting Device

A pure green microcavity organic light emitting device (MOLED) was designed and fabricated with an emission peak of 552 nm and the full width at half maximum (FWHM) of 24 nm. The maximum luminous efficiency and luminance are 8.4 cd/A at 13 V and 35000 cd/m2 at 21 V for the MOLED, and 3.2 cd/A at 18 V and 27000 cd/m2 at 25 V for the normal noncavity OLED. The luminous efficiency, voltage and current density are 6.3 cd/A, 7 V and 1.6 mA/cm2 for the MOLED, and 2.4 cd/A, 12 V and 4.2 mA/cm2 for the noncavity OLED at the luminance of 100 cd/m2. The CIE 1931 chromaticity coordinates of the MOLED at the normal direction is (0.35,0.62), which shows purer green emission comparing with that of the noncavity OLED (0.36,0.46).