Organic light-emitting diodes (OLEDs) with dual emission in the red and near-infrared regions offer a breakthrough opportunity for simplifying pulse oximetry technology. Here, a new class of bimetallic complexes Eu0.1Yb0.9(L)3Q (L = β-diketonates; Q = neutral ligands) with simultaneous emission at 612 and 978 nm has been reported, optimized for solution-processed OLEDs. A device based on Eu0.1Yb0.9(dbm)3thiadiazolophenanthroline (TDZP) exhibits the highest electroluminescence intensity in both spectral ranges and is employed as a single-pixel light source in a custom-built pulse oximeter prototype. The prototype demonstrates real-time measurement of heart rate and blood oxygen saturation in full agreement with commercial devices. This is the first demonstration of a fully functional OLED-based oximeter relying on dual-emissive lanthanide complexes. This results pave the way for next-generation wearable biomedical sensors using advanced emissive materials and simplified device architectures.

A new unique two-stage method for spinning hollow polynaphthoylenebenzimidazole (PNBI) fibers has been proposed. Polyacrylonitrile (PAN) fiber having a porous morphology was coated with poly(o-aminophenylene)- naphthoylenimide (PANI-O) precursor to form a composite fiber with a core–shell structure and subsequently this composite fiber precursor was heat treated in air. The inner PAN fiber underwent oxidative cyclization, accompanied by its high shrinkage, while the PANI-O shell, due to heterocyclization, turned into a PNBI-O shell, and the inner space of the hollow fiber was only partially filled with cyclized PAN.

ratiometric luminescent thermometers, particularly lanthanide-based, become very important, and long wavelength range is of particular interest due to low signal scattering. With this in mind, a series of new red and NIR emitting lanthanide Schiff base complexes were synthesized and characterized in detail for use as components of luminescent thermometers. Red-emitting europium complexes demonstrated high temperature sensitivity (up to 7 %/K) in the cryogenic temperature range (80-200 K), where the ligand-to-europium luminescence intensity ratio (LIR) was used as a signal. In contrast, NIR emitting ytterbium complexes demonstrated no sensitivity in the cryogenic range; however, their luminescence was sensitive to high temperatures (300-600 K), which is currently of particular interest. Ytterbium and europium complexes were also tested in OLEDs, and due to high temperature sensitivity, europium complexes were used for the first electroluminescent thermometers.

In this work, organic light-emitting LEDs based on Eu3+ coordination compounds with β-diketones and acetic and butyric acids were created and studied. At the moment, an active search is underway for new materials to create optoelectronic devices with high luminescent characteristics. One of these characteristics is high color purity and it can be achieved through the use of materials with narrow-band luminescence, for example, compounds based on Eu3+ ions. Complexes based on Eu3+ with 1,1,1-trifluoro4-phenyl-2,4-butanedione and acetic Eu(Cl)(Btfa)(CH3COO) (compound 1), butyric Eu(Btfa)2(CH3(CH2)3COO) (compound 2) acids were synthesized. The LEDs of the synthesized compounds were manufactured using a combined technique including the method of centrifugation and the method of thermal spraying in vacuum. The characteristics of the LEDs were measured by optical spectroscopy. To study the optical properties of the complexes, the powder was placed between two quartz substrates. Photoluminescence spectra were recorded using a SDL-1 spectrometer, an LED with a wavelength of 365 nm and a photoelectronic multiplier operating in linear mode. Electroluminescence spectra were obtained using the Ocean Optics Maya 2000 PRO spectrometer. A linear structure characteristic of Eu3+ ions was observed in the photoluminescence spectrum of the studied complexes. In the electroluminescence spectrum, radiation characteristic of Eu3+ ions is also observed, in addition to it, an additional wide band with a maximum at a wavelength of 390 nm and a half-height width of 61 nm is observed in the short-wavelength region. The operating voltage of the LED was 10 V. A characteristic “cold” white glow was observed for the studied LEDs. In the spectra of photos- and electroluminescence the following main transitions were found for the studied complexes: 5D0 → 7F0 (maxima at wavelengths λ1 = λ2 = 580 nm for compounds 1 and 2), 5D0 → 7F1 (split band, with maxima at wavelengths λ1 = 587 nm, λ2 = 593 nm, λ3 = 600 nm for the compound 1 and λ1 = 592 nm, λ2 = 599 nm for compound 2), 5D0 → 7F2 (split band, with maxima at wavelengths λ1 = 614 nm, λ2 = 619 nm, λ3 = 623 nm for compound 1 and λ1 = 614 nm, λ2 = 618 nm, λ3 = 620 nm for junction 2), 5D0 → 7F3 (split band, with maxima at wavelengths λ1 = 648 nm, λ2 = 652 nm, λ3 = 655 nm for junction 1 and λ1 = 652 nm, λ2 = 655 nm for compound 2). The wide band observed in the electroluminescence spectrum arises due to the contribution of the hole transport layer, due to the through flow of charge carriers through the active radiating layer, which leads to recombination in the PVK OLED layer. An analysis of the volt-ampere characteristics of the manufactured devices showed that they are characterized by two main conduction modes: the first corresponds to a limitation of the current by a spatial charge (0–7 V), the second is a limitation due to the processes of capture of charge carriers (7–23 V). The results of this work can be used in the production of industrial lighting.

For oximetry applications, the first dual red–near-infrared (NIR) emissive organic light-emitting diode (OLED) based on mixed-ligand complexes EuxYb1–x(dbm)3BPhen (x = 0; 0.01; 0.02; 0.05; 0.1; 1) is obtained. The photoluminescence quantum yields of the ytterbium and europium in the obtained complexes reach 0.9 and 31%, respectively, which are rather high values for the complexes of these ions. Dual visible–NIR emissive compounds EuxYb1–x(dbm)3BPhen are tested in OLEDs, and Eu0.05Yb0.95(dbm)3BPhen demonstrates the most intense electroluminescence both in visible (270 cd/m2) and NIR range (19 μW/cm2). The Eu0.05Yb0.95(dbm)3BPhen-based OLED is successfully used to produce the first lanthanide OLED-based pulsimeter prototype.

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

Terpolymers of acrylonitrile with acrylic acid and alkyl acrylates, including methyl-, butyl-, 2-ethylhexyl-, and lauryl acrylates, were synthesized using the reversible addition–fragmentation chain transfer method. In this study, the focus was on the investigation of the impact of different monomer addition methods (continuous and batch) on both the rheological behavior of the spinning solutions and the mechanical properties of the resulting fibers. Our findings revealed that the method of monomer addition, leading either to non-uniform copolymers or to a uniform distribution, significantly influences the rheological properties of the concentrated solutions, surpassing the influence of the alkyl-acrylate nature alone. To determine the optimal spinning regime, we examined the morphology and mechanical properties at different stages of fiber spinning, considering spin-bond and orientation drawings. The fiber properties were found to be influenced by both the nature and introducing method of the alkyl-acrylate comonomer. Remarkably, the copolymer with methyl acrylate demonstrates the maximum drawing ratios and fiber tensile strength, reaching 1 GPa. Moreover, we discovered that continuous monomer addition allows for reaching the higher drawing ratios and superior fiber strength compared to the batch method.

An approach to the luminance increase of the europium-based OLED is proposed through the formation of the mixed-ligand complex. The introduction of two diverse anionic ligands around one europium ion forming a mixed-ligand complex is confirmed by powder X-ray diffraction, 1H and 19F NMR spectroscopy, MALDI MS spectroscopy, and luminescence spectroscopy. A decrease in the symmetry of the coordination environment leads to a 50% reduction of the lifetime of the excited state. The obtained OLEDs based on mixed ligand europium complexes are significantly superior in luminance to OLEDs based on individual complexes.

A comparative study of electro- and photoluminescence properties of a novel coumarin dye and coumarin 6 is presented. It is shown that the electroluminescence spectrum of the new dye is red-shifted by 12 nm compared with its photoluminescence spectrum in a toluene solution. This result is explained by the presence of an anthracene-based group in the new coumarin dye, which prevents the formation of a dimeric structure in the organic light-emitting diode (OLED) active layer. Therefore, exciton emission prevails in electroluminescence in contrast to coumarin 6 emission caused by dimers. With the same OLED structures and almost identical I—V curves, significant differences in the voltage–luminance characteristics are observed, which are explained by the difference in electron mobilities of the studied compounds.

New ytterbium complexes K(Solv)x[Yb(Ln)2] (Solv = ethanol and/or water) with 2-tosylaminobenzylidene-aryloylhydrazones (H2L1, aryloyl = benzoyl; H2L2, aryloyl = 2-naphthoyl) demonstrated high solubility and hole mobility (ca. 2.6 × 10-6 cm2 V-1 s-1), while their electron mobility and PLQY were different. The substitution of a benzoyl substituent with naphthoyl resulted in a significant increase of the electron mobility (6.9 × 10-7vs. 1.7 × 10-6 cm2 V-1 s-1) and a decrease of the quantum yield (1.2% vs. 0.6%). As a result, the optimized OLEDs based on the K[Yb(Ln)2] layer demonstrated efficiencies up to 385 μW W-1 and 441 μW W-1, indicating the superior importance of charge mobility over the quantum yield. These are the highest efficiencies of the Yb electroluminescence.

The highest efficiency (430 μW W −1 ) of pure ytterbium luminescence obtained to date for Yb-based OLEDs was reached based on the ytterbium complex with halogenated Schiff base ligands.

Lanthanide complexes Ln(L)(HL) (H2L = 2-tosylamino-benzylidene-(2-benzo[d]thiazole) hydrazone; Ln = Yb, Gd) were obtained and thoroughly characterized. The monomeric structure of Yb(L)(HL)center dot Solv(1) (Solv(1) = 2CH(3)CN + 2EtOH + H2O) and the ligand structure were determined by single crystal X-ray diffraction data. Relatively high solubility (ca. 5 g/l) and quantum yield (0,9%), as well as mobility of electrons (2,33.10(-6) cm(2)/V.s) and holes (4,94.10(-7) cm(2)/V.s) of Yb(L)(HL) allowed its successful use as a host-free near-infrared OLED emission layer. OLED with the heterostructure ITO/PEDOT:PSS/poly-TPD/Yb(L)(HL)/OXD-7/LiF/Al demonstrated pure 1000 nm centred near-infrared luminescence with the external quantum efficiency up to 0.025%, which is one of the highest value for 1000 nm centred electroluminescence.

An increase in the efficiency for a terbium-based OLED was achieved by introducing gold nanoparticles into the PEDOT:PSS hole injection layer and was mainly due to the improvement in carrier injection and the reduction of the excited-state lifetime. The introduction of plasmon-resonant gold nanoparticles resulted in a 50% increase in the Tb(czb)(3)TDZP luminance, which reached 480 cd m(-2) and is the highest result for OLEDs based on aromatic carboxylates.

Polyacrylonitrile terpolymers based on acrylonitrile, acrylic acid, and methyl acrylate were synthesized by reversible addition–fragmentation chain-transfer polymerization with varying the monomer addition sequence during the synthesis. The monomer introduction sequence in the synthesis of a ternary copolymer significantly affects both the rheological properties of solutions and the strength of obtained fibers.

A prototype of a vehicle automatic positioning system is developed based on luminescent labels containing terbium and europium 1,3-diketonates embedded in a polymer matrix. The system excited with ultraviolet LEDs reliably identifies the label in the presence of solar stray light.

The results of studying the luminescent properties of organic light-emitting diodes based on new luminescent compounds containing a coumarin fragment are presented.The light-emitting diodes were fabricated by spin-coating and thermal evaporation in an argon atmosphere in a clean room.Measurements of the LED characteristics were carried out by optical spectroscopy, as well as by electrical methods.It has been experimentally shown that deposition of an OLED active layer based on luminescent compounds containing a coumarin core can lead to the formation of dimers, the luminescence spectra of which differ significantly from the corresponding spectra of the original materials in toluene.A variation in the structure of the compound leads to a change in both the current-voltage characteristics of the resulting device and the luminescence spectra.These changes appeared due to the difference in the electronic structure of these materials as well as due to different values of charge carrier mobilities and the potential barriers at the heterointerface with other OLED layers.The results obtained may serve as the basis for systematizing knowledge about the dependence of the properties of new luminescent materials, which include a coumarin core, on their structure.The developed structures can become prototypes for industrially produced light-emitting devices that specifically emit white light.

An approach to the directed synthesis of aromatic lanthanide carboxylates as promising candidates for various luminescent applications, first of all, as emitting layers in light-emitting diodes, by varying the conjugation length with the introduction of a heteroatom and a neutral ligand was proposed. This approach enabled the synthesis of new europium and ytterbium complexes with naphtho[1,2]thiazole-2-carboxylic and naphtho[2,1]thiazole-2-carboxylic acid anions, which were successfully used in light-emitting diodes.

The well-known system of dinuclear Cu(I) complexes bridged by 2-(diphenylphosphino)pyridine (PyrPhos) derivatives Cu2X2L3 and Cu2X2LP2 (L = bridging ligand, P = ancillary ligand) goes along with endless variation options for tunability. In this work, the influence of substituents and modifications on the phosphine moiety of the NP-bridging ligand was investigated. In previous studies, the location of the lowest unoccupied molecular orbital (LUMO) of the copper complexes of the PyrPhos family was found to be located on the NP-bridging ligand and enabled color tuning in the whole visible spectrum. A multitude of dinuclear Cu(I) complexes based on the triple methylated 2-(bis(4-methylphenyl)phosphino)-4-methylpyridine (Cu-1b-H, Cu-1b-MeO, and Cu-1b-F) up to complexes bearing 2-(bis(4-fluorophenyl)phosphino)pyridine (Cu-6a-H) with electron-withdrawing fluorine atoms over many other variations on the NP-bridging ligands were synthesized. Almost all copper complexes were confirmed via single crystal X-ray diffraction analysis. Besides theoretical TDDFT-studies of the electronic properties and photophysical measurements, the majority of the phosphino-modified Cu(I) complexes was tested in solution-processed organic light-emitting diodes (OLEDs) with different heterostructure variations. The best results of the OLED devices were obtained with copper emitter Cu-1b-H in a stack architecture of ITO/PEDOT-PSS (50 nm)/poly-TPD (15 nm)/20 wt % Cu(I) emitter:CBP:TcTA(7:3) (45 nm)/TPBi (30 nm)/LiF(1 nm)/Al (>100 nm) with a high brightness of 5900 Cd/m2 and a good current efficiency of 3.79 Cd/A.

New fluorescent D-A-D dyes containing 9-(p-tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a donor unit and 2,1,3-benzochalcogenadiazoles as an electron-withdrawing group were synthesized. The photoluminescent and electroluminescent properties of novel dyes for fluorescent OLED application were investigated. It was demonstrated that the replacement of lightweight heteroatoms by heavier ones enables the fine tuning of the maximum emission without significantly reducing the luminescence quantum yield. The maximum quantum yield value of 62.6% for derivatives based on 2,1,3-benzoxadiazole (1a) in cyclohexane was achieved. Two devices with the architecture of glass/ITO/PEDOT-PSS/poly-TPD/EML/TPBi/LiF/Al (EML = emitting layer) were fabricated to check the suitability of the synthesized compounds as a single active emission layer in OLED. These OLEDs exhibited clear red electroluminescence of the dyes with the maximum current efficiency of 0.85 Cd/A.

OLEDs based on lanthanide complexes have decisive optical advantages but are hampered by low brightness. Despite the efforts to optimize several parameters such as quantum yield and charge carrier mobility, there seems to be another key parameter that hinders their performances. Experimental data are therefore collected for mixed-ligand europium complexes with bathophenanthroline and different classes of anionic ligands and screened to identify the key parameter responsible for this situation, which turns out to be the long lifetime of their excited states. A broad literature search supports this conclusion, showing that lanthanide complexes are inferior to other classes of OLED emitters often because of their long lifetimes; furthermore, among a series of lanthanide complexes, the best results are achieved for those with the shortest lifetimes, even though they suffer from low quantum yields.