Laboratory of Polysulphur-Nitrogen Heterocycles (N31)

• Chemistry of new polysulfur- and sulfur-nitrogen heterocyclic systems;
• New methods for the synthesis of heterocycles containing several nitrogen and sulfur or selenium atoms;
• Organic materials: solar cells, OLEDs, semiconductors, nonlinear optical and liquid crystal materials;
• Radicals, cation- and anion-radicals of sulfur(selenium)-nitrogen heterocyclic systems.

Non-fullerene acceptors and the creation of bulk heterojunction solar cells with increased photovoltaic efficiency.

✓ Researchers at the Institute of Organic Chemistry of the Russian Academy of Sciences have developed an efficient method for synthesizing a new electron-deficient heterocyclic system, dithienobenzo-bis-thiadiazole. Using this method, they, together with Chinese partners from Nankai University, synthesized polymeric donors—essential components of the active layer of organic solar cells. It was shown that the polymers not only possess a wide optical band gap exceeding 2.0 eV but also exhibit deep-lying energy levels of the highest occupied molecular orbital. Binary solar cells were constructed using the synthesized donor polymers and the commercially available non-fullerene acceptor L8-BO-X, one of which demonstrated a high photovoltaic efficiency of 16.34%, demonstrating the potential of this family of polymeric donors.

In 2025, a paper was published in a prestigious Q1 journal J. Mater. Chem. C., DOI: 10.1039/D5TC01406A

✓  Researchers from the Institute of Organic Chemistry of the Russian Academy of Sciences, together with their Chinese partners from Nankai University, have developed a new synthetic approach to constructing polyaromatic fused structures as components of non-fullerene acceptors for organic solar cells using a cycloaromatization strategy based on the Hinsberg reaction. The resulting non-fullerene acceptors, CD-1 and CD-2, exhibit a compact three-dimensional interpenetrating network structure with a high packing coefficient in a single crystal and, consequently, high electron transfer capacity, as evidenced by high electron mobility of over 1.1 cm² V² s² in CD-2-based organic field-effect transistors. Notably, the additive-free binary organic solar cells based on CD-1 and CD-2 demonstrated near-record photovoltaic efficiencies of 19.6% and 19.1%, respectively, with well-balanced open-circuit voltage and short-circuit current density. These results highlight the potential of a new molecular design strategy for developing high-performance non-fullerene acceptors

In 2025, a paper was published in a prestigious Q1 journal Energy & Environmental Science, DOI: 10.1039/D5EE00031A.

✓ The researchers from the Institute of Organic Chemistry of the Russian Academy of Sciences have developed mild conditions for the preparation of 3-thiosubstituted 9-oxo-1-hetaryl-9H-indeno[2,1-c]pyridine-4-carbonitriles in quantitative yields in the reaction of readily available 2-(3-oxo-2-arylidene-2,3-dihydro-1H-inden-1-ylidene)malononitrile with S-nucleophiles. The developed procedure turned out to be simpler and more efficient compared to the known methods for the synthesis of 3-amino-substituted 9-oxo-1-hetaryl-9H-indeno[2,1-c]pyridine-4-carbonitriles in a two-step approach. The possibility of using the synthesized thiosubstituted 2-azafluorenones as terminal groups in non-fullerene acceptors (NFA) for organic solar cells is demonstrated. The key characteristics of the new NFAs with functional end groups were assessed and compared with known analogues described in the literature.

In 2025, a paper was published in a prestigious Q2 journal Synthesis, DOI: 10.1055/a-2681-5727.

Creation of new highly efficient infrared organic light-emitting diodes (OLEDs)

✓ Researchers at the Institute of Organic Chemistry of the Russian Academy of Sciences, together with colleagues from the Lebedev Physical Institute, synthesized asymmetrical fluorescent compounds of the D–A–A type based on fused 1,2,5-thiadiazoles with an acceptor cyano group. These compounds exhibited fluorescence from a twisted state with intramolecular charge transfer (TICT)—a photochemical process in which an electron is transferred from an electron-donating group to an electron-withdrawing group, followed by twisting of the molecular structure. To obtain these molecules, we found conditions for several sequential reactions of substitution of two bromine atoms in the starting molecule via cyanation and Suzuki-Miyaura cross-coupling. The results showed that the introduction of a cyano group and a carbazole donor moiety into the fused 1,2,5-thiadiazole molecule, depending on the position of the nitrogen atom in the internal acceptor block, leads to planarization of the structure in the excited state due to the formation of an N-H hydrogen bond between the nitrogen and hydrogen atoms of the donor block. This results in a strong bathochromic shift in the luminescence spectrum. This opens new possibilities for the development of highly luminescent organic dyes for use in fluorescent probes, sensors, and solar cells.

In 2025, a paper was published in a prestigious Q1 journal “Dyes and Pigments”, DOI: 10.1016/j.dyepig.2025.112761.

✓ Researchers at the Institute of Organic Chemistry of the Russian Academy of Sciences (IOC RAS) studied the influence of heavy atoms (sulfur and selenium) on the photophysical and electroluminescent properties of thermally activated delayed fluorescence (TADF) emitters based on β-diketones. Two new dyes with a D-π-A-π-D structure were synthesized, containing phenothiazine (PTZPDO) and phenoselenazine (PSeZPDO) donor fragments. Ab-initio quantum chemical calculations (SA-CASSCF) show that the introduction of sulfur and selenium atoms significantly affects the electronic structure and leads to different photoluminescence spectra. It was shown that although heavy atom substitution enhances spin-orbit coupling, it also increases the singlet-triplet energy gap (ΔEST), reducing the efficiency of inverse intersystem crossing and allowing competition between TADF and triplet-state phosphorescence in PSeZPDO-doped films. The PTZPDO-based OLED device was found to exhibit bright emission with a peak luminance of 9800 cd/m², outperforming the PSeZPDO-based device in TADF emission efficiency. These results demonstrated the high potential of heavy atom-modified β-diketone-based TADF emitters for energy-efficient OLED applications and highlighted the importance of optimizing the molecular design to balance the photophysical performance of the device.

In 2025, a paper was published in a prestigious Q1 journal “Optical Materials”, DOI: 10.1016/j.optmat.2025.117470.

3. Синтез новых электроноакцепторных строительных блоков для фотовольтаических и светоизлучающих устройств

✓ Researchers from the Institute of Organic Chemistry of the Russian Academy of Sciences, together with colleagues from the N.N. Vorozhtsov Institute of Organic Chemistry of the Russian Academy of Sciences and the P.N. Lebedev Physical Institute of the Russian Academy of Sciences, have studied the neutral and ion-radical states of fused phenanthro- and dibenzoquinoxalino-1,2,5-thia(selena)diazoles using thermogravimetry/differential scanning calorimetry, spectroelectrochemistry and optical spectroscopy, cyclic voltammetry, and electron paramagnetic resonance. It has been shown that, compared to the archetypal 2,1,3-benzothiadiazole, π-expansion and the replacement of S with Se jointly lead to an increase in the adiabatic electron affinity, a decrease in the absolute values of the CV potentials, and broadening and bathochromic shifts of the UV spectral bands. The obtained data indicate that the studied structures are promising organic dyes/non-fullerene electron acceptors for molecular optoelectronics.

In 2025, a paper was published in a prestigious Q1 journal “Dyes and Pigments”, DOI: 10.1016/j.dyepig.2025.112922.

4. Обзор по химии Херца

✓ A researcher from the Institute of Organic Chemistry of the Russian Academy of Sciences (IOC RAS) contributed to an analysis of the key achievements of Hertz chemistry over its first century, as well as the challenges and prospects for its further development. The discussion focused on the synthesis, structure, and reactivity of π-heterocycles—derivatives of the (het)arene-annelated 1,2,3-dichalcogenazole system with chalcogens S, Se, and, less commonly, Te—in various spin and charge states, encompassing cations, radicals, bipolar ions, and antiaromatic/diradicaloid quinoids. These compounds are important for the development of both fundamental chemistry and materials chemistry, particularly for the design and synthesis of metal-free conductive, magnetic, and optoelectronic materials. The extension of Hertz chemistry to other non-transition elements is discussed.

In 2025, a paper was published in a prestigious Q1 journal “Russian Chemical Reviews”, DOI: 10.59761/RCR5146.

Dye-sensitized solar cell fabrication and testing center

✓ Researchers at Laboratory No. 31 of the IOC RAS, using the IOC RAS instrumentation, are constructing prototypes of dye-sensitized solar cells based on both new compounds obtained in the laboratory and commercially available dyes. To create the solar cells, the team has access to equipment including ultrasonic and UV cleaners for the working surface of electrodes, stencils for applying semiconductor layers using the doctor-blade method, programmable muffle furnaces, a vacuum system for injecting electrolyte into the sample, and other necessary equipment. The resulting devices are tested using a state-of-the-art photovoltaic efficiency meter from Sciencetech (Canada) with a certified AM 1.5G radiation source with a luminous flux of 100 mW cm^-2 and a Keithley 2400 potentiostat.