Properties Of Organic Materials Research Articles

Efficient Derivatization of a Thienobenzobisthiazole-Based π-Conjugated Polymer Through Late-Stage Functionalization Towards High-Efficiency Organic Photovoltaic Cells.

Derivatization is essential for optimizing organic material properties. However, because functional groups are often introduced at an early stage of the synthesis, similar intermediates have to be repeatedly synthesized to produce derivatives, which amounts to a daunting and time-consuming task. Using thienobenzobisthiazole (TBTz) as a building unit of donor polymers for organic photovoltaics (OPVs), we demonstrate an efficient derivatization of a TBTz-based π-conjugated polymer by late-stage functionalization. In the developed synthetic route, functional groups are introduced at the last step of monomer synthesis, enabling us to easily synthesize several derivatives from a common intermediate. Ester and acyl groups are introduced into the polymer instead of the alkyl group, giving rise to deep HOMO energy levels and resulting in OPV cells with high open-circuit voltage even in the absence of halogen substituents that are typically introduced into the donor polymers. Notably, the ester-functionalized TBTz-based polymer shows a small nonradiative voltage loss (ΔVnr) of 0.19 V and has one of the highest charge generation efficiencies among the halogen-free donor polymers with similar ΔVnr, improving the critical trade-off relationship between voltage loss and charge generation. Our results provide an important guideline for the efficient development of high-performance polymers for OPVs.

Efficient Derivatization of a Thienobenzobisthiazole‐Based π‐Conjugated Polymer Through Late‐Stage Functionalization Towards High‐Efficiency Organic Photovoltaic Cells

AbstractDerivatization is essential for optimizing organic material properties. However, because functional groups are often introduced at an early stage of the synthesis, similar intermediates have to be repeatedly synthesized to produce derivatives, which amounts to a daunting and time‐consuming task. Using thienobenzobisthiazole (TBTz) as a building unit of donor polymers for organic photovoltaics (OPVs), we demonstrate an efficient derivatization of a TBTz‐based π‐conjugated polymer by late‐stage functionalization. In the developed synthetic route, functional groups are introduced at the last step of monomer synthesis, enabling us to easily synthesize several derivatives from a common intermediate. Ester and acyl groups are introduced into the polymer instead of the alkyl group, giving rise to deep HOMO energy levels and resulting in OPV cells with high open‐circuit voltage even in the absence of halogen substituents that are typically introduced into the donor polymers. Notably, the ester‐functionalized TBTz‐based polymer shows a small nonradiative voltage loss (ΔVnr) of 0.19 V and has one of the highest charge generation efficiencies among the halogen‐free donor polymers with similar ΔVnr, improving the critical trade‐off relationship between voltage loss and charge generation. Our results provide an important guideline for the efficient development of high‐performance polymers for OPVs.

Construction frontier molecular orbital prediction model with transfer learning for organic materials

The frontier molecular orbitals of organic semiconductor materials play a crucial role in the performance of photoelectric devices, including organic photovoltaics (OPVs), organic light-emitting diodes (OLEDs), and organic photodetectors (OPDs). In this work, a model for predicting frontier molecular orbital of organic materials, including HOMO and LUMO levels, is established with the extreme gradient boosting algorithm and Klekota-Roth fingerprints. The correlation coefficients of HOMO or LUMO energy levels in the testing set are 0.75 and 0.84 in the transfer model from 11,626 DFT data in Harvard Energy database to 1198 experimental data in literature. The difference between the ML predicted value and the experimental value is smaller than the difference between ML prediction and DFT calculation, always less than 10%. Moreover, based on correlation and SHAP interpretability analysis, 13 key structural fragments influencing energy levels are selected to further verify the effective regulation of the frontier molecular orbital by the key structural fragments in practical applications. Considering the completely opposite regulatory functions of key structural fragments on HOMO and LUMO energy levels, four new Y6 derivatives, Y-PCP, Y-P6F, Y-PCF, and Y-P4FC, are designed to flexibly modify the HOMO and LUMO energy levels. The prediction trends of ML align closely with the computational trends from DFT. It is worth noting that the accuracy of LUMO energy level prediction by the prediction model makes up for the instability of DFT calculation on LUMO energy level. This work offers a cost-effective method to accelerate the acquisition of electronic properties of organic materials.

Temperature-dependent charge transport measurements unveil morphological insights in non-fullerene organic solar cells

The morphological analysis of bulk heterojunction (BHJ) active layer stands as a critical imperative for advancing the performance of future organic solar cells. Conventional characterization tools employed for morphological investigation often require substantial resources, both in cost and physical space, thereby imposing restraints on research endeavors in this domain. Here, we extend the application of charge carrier transport characterization beyond conventional mobility assessments, utilizing it as a table-top method for preliminary morphological screening in organic thin films. The investigation focuses on several high-performance BHJ systems that utilize typical “Y” non-fullerene acceptors. It involves in-depth transport studies, including temperature- and field-dependent transport characterizations. The resulting transport data are analyzed in detail using the Gaussian disorder model to extract key transport parameters, specifically the high-temperature limited mobility (μ∞) and positional disorder (∑). Integrating these transport parameters with morphological insights obtained through various characterization tools—including x-ray scattering, sensitive spectroscopy, and quantum chemistry simulation—provides a deep understanding of the intricate interplay between charge transport properties and morphological characteristics. The results reveal explicit relationships, associating μ∞ with the degree of molecular stacking in BHJs and ∑ with the structural disorder in molecule skeleton. Our findings point to the promising potential of utilizing a simple transport characterization technique for the early stage evaluation of thin film packing and geometric properties of organic materials.

Cleavable azobenzene linkers for the design of stimuli-responsive materials.

The azo linkage (NN) is one of the very few functional groups in organic chemistry that exhibits sensitivity towards thermal, chemical, photochemical, and biological stimuli. Consequently, this property has given rise to a distinct class of responsive materials. For example, thermal sensitivity has led to generation of free radical initiators useful in curing and polymerization applications. Chemically-induced cleavage has aided the development of self-immolative polymers and reactive scaffolds for proteomics applications. Photo-isomerization capability has given rise to photo-responsive systems. Azobenzene cleavage in biologically reducing environments, such as that of the colon, and under tumor hypoxia conditions has led to diagnostic, therapeutic, and delivery materials. Such conditions have also allowed for control over formation (assembly) and disruption (disassembly) of micellar nanoparticles. The aim of this review article is to look beyond the prevalent photosensitivity aspect of the aromatic azo compounds and draw attention to the azo scission reaction as a trigger of the change in the structure and properties of organic materials. Thus, the main discussion begins with the mechanism of the reductive cleavage. Then, its application in the design of molecules that can be activated as drugs and fluorescent sensors, (nano)materials with potential to release active substances, and polymers with side-chain and main-chain self-immolative capacity is discussed. Finally, the status and future challenges in this field are discussed.

Regioisomerism in Thienothiophene-Based Covalent Organic Frameworks─A Tool for Band-Gap Engineering.

The craft of tuning optical properties is well-established for crystalline inorganic and hybrid solids. However, a far greater challenge is to tune the optical properties of organic materials systematically by design. We now introduce a synthesis concept that enables us to alter the optical properties of crystalline covalent organic frameworks (COFs) systematically using isomeric structures of thienothiophene-based building blocks (T23/32T) combined with a variety of tetratopic aromatic amines, e.g., the Wurster moiety (W-NH2). This concept is demonstrated for the synthesis of COFs in bulk and film forms and provides highly crystalline and porous isomeric COFs featuring predesigned photophysical properties. The band gap of the framework can be tuned continuously and precisely by chemically doping the pristine W23TT COF with its related constitutional isomer building block. Density-functional theory investigations of COF model compounds indicate that the extent of π-conjugation is among the key characteristics enabling the band-gap engineering.

Fully Screen‐Printed, Flexible, and Scalable Organic Monolithic Thermoelectric Generators

AbstractEnergy‐harvesting technologies offer a sustainable, maintenance‐free alternative to conventional energy‐storage solutions in distributed low‐power applications. Flexible thermoelectric generators (TEGs) can generate electric power from a temperature gradient, even on complex surfaces. Organic materials are ideal candidates for flexible TEGs due to their good solution‐processability, natural abundance, low weight, and flexibility. Electronic and thermoelectric properties of organic materials have steadily progressed, while device architectures leveraging their advantages are largely missing. Here, a design and fabrication method are proposed for producing fully screen‐printed, flexible monolithic organic TEGs scalable up to m2, compatible with any screen‐printable ink. This approach is validated, along with its scalability, by printing TEGs composed of two different active inks, in three configurations, with up to 800 thermoelements, with performances well matching simulations based on materials parameters. It is demonstrated that by using an additive‐free graphene ink, a remarkable power density of 15 nW cm−2 at ΔT = 29.5 K can be achieved, with an estimated weight‐normalized power output of 1 µW g−1, highlighting a strong potential in portability. Owing to such power density, only limited areas are required to generate microwatts, sufficient for operating low‐power electronic devices such as sensors, and wearables.

The influence of selenophene π-linker on photovoltaic properties of pyrrole-4,6(5-H)-dione-based chromophores: A quantum chemical study

A series of 4-H-selenopheno[3,4-c]pyrrole-4,6(5-H)-dione based chromophores (DMSD1-DMSD7) was designed via the introduction of selenophene units (n = 2–7) in the π–spacer of reference compound (DMSR) owing to growing demand of non-fullerene based organic solar cells. The influence of selenophene π–spacer on photovoltaic properties of entitled molecules was explored by utilizing CAM-B3LYP/6-311G (d,p) functional. All the designed compounds were found with lesser values of energy gaps (4.342–3.904 eV) as compared to DMSR (4.764 eV). Similarly, their absorption values were found in the visible region (523.560–533.403 nm) in dichloromethane solvent. Moreover, the entitled chromophores exhibited lower binding energies (1.895–1.566 eV) with higher open circuit voltage values which supported their excellent charge transference properties. The unique properties like least value of bandgap (3.904 eV) with greater charge transfer phenomena were examined for DMSD7 due to the presence of most elongated chain of selenophene-based π–spacer. The density of state and transition density matrix maps illustration further confirmed the efficient charge transfer in DMSD7. Overall, these findings disclosed that by utilizing selenophene π–spacer, photovoltaic properties of organic materials can be efficiently improved.

Quantum chemical study of symmetricalnon-fullerene acceptor chromophores for organic photovoltaics

It is well reported that the fused ring acceptor modification can be an effective method for improving the optoelectronic and photovoltaic properties of organic materials. The addition of acceptor groups to a core can enhance its electron-withdrawing ability, resulting in improved charge transport and higher power conversion efficiencies in organic solar cells (OSCs). Thieno[3,2-b]thiophene, and diketopyrrolopyrrole are commonly used groups in OSCs due to their powerful electron-withdrawing capabilities and well-established synthetic protocols. Their incorporation into donor–acceptor systems has been shown to enhance the materials absorption spectra, increase the open-circuit voltage (VOC), and improve device performance. Following integrating several acceptor groups onto the recently synthesized core based on thieno[3,2-b]thiophene, and diketopyrrolopyrrole, we have created six novel electron donors (BDPTM1-BDPTM6) with interesting optoelectronic and photovoltaic properties. It is indeed common practice to use computational methods such as density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to investigate the optoelectronic and photovoltaic properties of newly created molecules. These methods allow researchers to obtain crucial parameters such as the HOMO and LUMO energies, energy gap (Egap), frontier molecular orbital alignment, density of states, molecular electrostatic potential, absorption maxima (λmax), excitation energy (Eex), binding energy and transition density matrix…… Among all the designed compounds, BDPTM3 exhibited the lowest energy bandgap (1.63 eV) with bathochromic shift of 921.610 nm in Dichloro-methane and 852.242 nm in gaseous phase. BDPTM2 displayed the highest dipole moment (µtot) at 7.557 eV, BDPTM5, and BDPTM6 demonstrated consistent linear polarizability〈α〉 at 191.612 × 10−22 esu and 196.2823 × 10−22 esu respectively. Notably, BDPTM6 calculated the highest frst hyperpolarizability βtot at 583.849 × 10–30. Based on the results obtained from the theoretical investigation of the optoelectronic and photovoltaic properties of the developed molecules, it may be possible to recommend them as better candidates for use in organic solar cells (OSCs).

Controlling the Manifold of Polariton States Through Molecular Disorder

AbstractExciton polaritons, arising from the interaction of electronic transitions with confined electromagnetic fields, have emerged as a powerful tool to manipulate the properties of organic materials. However, standard experimental and theoretical approaches overlook the significant energetic disorder present in most materials now studied. Using the conjugated polymer P3HT as a model platform, the degree of energetic disorder is systematically tuned and a corresponding redistribution of photonic character within the polariton manifold is observed. Based on these subtle spectral features, a more generalized approach is developed to describe strong light‐matter coupling in disordered systems that captures the key spectroscopic observables and provides a description of the rich manifold of states intermediate between bright and dark. Applied to a wide range of organic systems, the method challenges prevailing notions about ultrastrong coupling and whether it can be achieved with broad, disordered absorbers.

Interaction strength in molecular junctions consisting of π-stacked antiaromatic molecules

The interaction force was measured as the adhesive force acting between norcorrole molecules anchored to the probe surface and the sample surface. This study reveals substantial interactions in π-stacked antiaromatics at the single-molecule scale.

ПРОГРЕСС В ТЕХНОЛОГИИ OLED И ЕЕ ПРИМЕНЕНИЕ В ДИСПЛЕЯХ СЛЕДУЮЩЕГО ПОКОЛЕНИЯ

This paper reviews the progress in organic light-emitting diode (OLED) technology and its application in next-generation displays. It focuses on the improvements in organic material properties, novel manufacturing techniques, and innovations in flexible, transparent, and energy-efficient displays. Advances in OLED brightness, contrast, and durability are explored, as well as new deposition and manufacturing techniques such as ink-jet printing and laser lithography. The applications of OLED in modern devices, including smartphones, televisions, wearables, automotive displays, and billboards, are analyzed in terms of their advantages and limitations. The advantages and disadvantages of OLED technology are discussed, as well as the prospects for its development and implementation in the future.

Organoboron flank-substituted donor-acceptor polymer anode with ultra-long cycling stability for lithium ion batteries.

The tunable structure and other properties of organic materials suggest that they can potentially solve the shortcomings of traditional anodes such as graphite. We successfully introduced an organoboron unit into the thiophene-based polymer PBT-2 to construct a donor-acceptor polymer anode. The charge delocalization and LUMO energy level resulting from the unique structure of this material enabled good redox activity and a very stable electrochemical performance in electrochemical tests, with a reversible capacity of 262 mA h g-1 at 0.5 A g-1 and >10 000 cycles at 1 A g-1 with a decay of 0.056‰ per cycle. Accordingly, targeted structural design to overcome the shortcomings of active units such as thiophene can effectively regulate their electrochemical performance, providing a solution for the development of high-performance anode materials for use in lithium ion batteries.

Implementation of multi-criteria decision making for the ranking of drugs used to treat bone-cancer

<abstract> <p>The concept of "topological index" refers to a numerical value determined by the structure of a chemical network. It serves to determine the physicochemical and biological properties of diverse medications, offering a more precise depiction of the theoretical properties of organic materials, this is achieved through the utilization of degree-based topological indices. Because of the development of resistance to existing treatments and the unpleasant side effects associated with some current drugs, the hunt for new drugs remains a priority. In drug discovery, QSPR approaches are widely used to predict, from a chemical structure, the biological activity of potential novel drugs. Researchers can prioritize compounds for synthesis and optimize them to improve potency, preference, and other desired attributes by establishing a correlation between chemical features and biological activity. Rational drug design approaches incorporate research methodologies such as quantitative structure-activity relationships (QSAR) and quantitative structure-property relationships (QSPR), along with decision-making strategies. The goal of these strategies is to improve the biological activity and physicochemical qualities of existing leads. This research includes mathematical modeling of drug mechanisms utilizing multiple-criteria decision analysis and QSPR analysis. Furthermore, using decision-making techniques, I can determine the order of production for various drugs used to treat bone cancer based on their examination using QSPR analysis and topological indices.</p> </abstract>

Controllable π-π coupling of intramolecular dimer models in aggregated states.

π-π coupling as a common interaction plays a key role in emissions, transport and mechanical properties of organic materials. However, the precise control of π-π coupling is still challenging owing to the possible interference from other intermolecular interactions in the aggregated state, usually resulting in uncontrollable emission properties. Herein, with the rational construction of intramolecular dimer models and crystal engineering, π-π coupling can be subtly modulated by conformation variation with balanced π-π and π-solvent interactions and visualized by green-to-blue emission switching. Moreover, it can rapidly respond to temperature, pressure and mechanical force, affording a facile way to modulate π-π coupling in situ. This work contributes to a deeper understanding of the internal mechanism of molecular motions in aggregated states.

Additional of Organic Amendments in the Soil to Increase the Various Crop Yield: A Review

Agricultural production is threatened by the scarcity of current natural resources, an increasing total population, climatic change, and degraded soils. To feed the world's growing population, development strategies must be implemented that sustainably increase agricultural production while at the same time reducing the negative impacts of the activities. A number of amendments are currently being researched to improve the structure and fertility of soils. The properties of organic materials (biochar (BC), husk, and compost) were examined. The properties of BC have a large specific surface area, are highly porous, and have a high cation exchange capacity (CEC). These amendments could be used to slow down the continuous soil degradation and maintain soil productivity while facing global challenges. While the environmental effects have been extensively studied, the extent to which they can contribute to long-term intensification has yet to be determined. This review aims to contribute to the topic by providing a concise summary that combines both environmental evidence and agronomic considerations.

Cylindrical cavity resonator for complex permittivity estimation at 1.2853 GHz: Coir and skins of rice, banana, lemon, watermelon, pineapple and papaya

The knowledge of dielectric properties of organic materials at microwave frequencies is important for different applications in agriculture, food, or other similar research areas. The method of the low-cost disturbed cylindrical cavity resonator is a common measurement technique that considers resonant frequency shift when inserting samples of materials inside the cavity. Frequency shifts together with the knowledge of the complex permittivity of a reference material allow the estimation of the permittivity of a material under test. In this paper, the complex permittivity, and the loss tangent of dried and powdered agricultural wastes from the state of Colima in Mexico are obtained at 1.2853. The materials under test are coir and skins of rice, banana, lemon, watermelon, pineapple, and papaya since they are one of the most abundant agricultural wastes in the state of Colima in Mexico.

Assessing n‐type organic materials for lithium batteries: A techno‐economic review

AbstractThe high demand for critical minerals such as lithium, copper, nickel, and cobalt, required for lithium‐ion batteries, has raised questions regarding the feasibility of maintaining a steady and affordable supply of raw materials for their production. In the last years, researchers have shifted their attention toward organic materials, which are potentially more widely available, affordable, and sustainable due to the ubiquitous presence of the constituent organic elements. The n‐type materials have a redox mechanism analogous to that of lithium‐ion cathodes and anodes, hence they are suitable for a meaningful comparison with the state‐of‐the‐art technology. While many reviews have evaluated the properties of organic materials at the material or electrode level, herein, the properties of n‐type organic materials are assessed in a complex system, such as a full battery, to evaluate the feasibility and performance of these materials in commercial‐scale battery systems. The most relevant cathode materials for organic batteries are reviewed, and a detailed cost and performance analysis of n‐type material‐based battery packs using the BatPaC 5.0 software is presented. The analysis considers the influence of electrode design choices, such as the conductive carbon content, active material mass loading, and electrode density, on energy density and cost. The potential of n‐type organic materials as a low‐cost and sustainable solution for energy storage applications is highlighted, while emphasizing the need for further advancements of organic materials for energy storage applications.image

Study on the influence of chain extension and substituent position on charge transport properties and optoelectronic properties based on 2,5-di(pyrazine-2-yl)furan derivatives

In this paper, the basic structure of 2,5-di(pyrazine-2-yl)furan (DPF) was initially designed to tune the charge transport properties and photoelectric properties of organic materials by chain extension. Through the calculation of recombination energy, the structure with the introduction of anthracene group (DPF-A) is a stable P-type material with the smallest recombination energy in terms of adiabatic ionization potential, so the chain extended molecule DPF-A was selected as the base for the study of substituent positions. While thiophene, trifluorinated acyl, and methoxy groups were introduced to design DPF-A series derivatives. Density functional theory with high computational accuracy was applied to investigate geometric structure, orbital energy levels, ionization energy, electron affinity energy, and recombination energy. The results show that the increase (decrease) of the HOMO (LUMO) energy level leads to the red (blue)-shift of absorption wavelength and fluorescence emission wavelength; the vertical ionization potential decreases and the vertical electron affinity potential increases, thus the hole and electron injection barrier decreases; the decrease of the hole/electron recombination energy improves the charge transport ability of the molecule. Moreover, the adjustment of thiophene orientation and the position of the introduced group has the potential to transform the p-type material into an n-type material, resulting in the enhanced electron injection ability.

Study of Seebeck coefficient in organic materials under nonlinear temperature distributions

Environmental issues and energy crisis are huge challenges in today’s world. As one of green energy sources, thermoelectric (TE) materials have attracted tremendous attraction for they can convert free heat energy to electricity. In our work, through the master equation (ME) method, we studied the characteristics of charge transport in the organic material under nonlinear temperature distributions. Under each temperature distribution, Seebeck coefficient is analyzed with different factors such as the temperature, the reorganization energy and the energetic disorder strength. Especially, Seebeck coefficient of different temperature distributions showed different performances when the reorganization energy changes. Our studies will be helpful to look further into TE properties of organic materials and improve the application of TE devices.