Search Results (33)

A series of donor–acceptor π-conjugated polymers based on Difluorophenazine acceptor and benzodithiophene donor units with different substituents, hydrogen (H), chlorine (Cl), fluorine (F), and sulfur (S), was designed and synthesized to investigate how donor-side substituent modification influences optoelectronic properties. The substituent variation systematically modulated the optical band gaps (1.72–1.82 eV) and HOMO energy levels (−5.42 to −5.58 eV). When applied in bulk heterojunction solar cells with the Y6 acceptor, these polymers delivered power conversion efficiencies ranging from 3.85% to 7.79%. The fluorinated polymer P(BDTTF-TffPzT) exhibited the best performance, with J_sc = 19.65 mA cm⁻², V_oc = 0.825 V, and FF = 0.481. These findings establish that donor-side substituent engineering is an effective molecular design strategy for tuning optoelectronic properties and device performance in phenazine-based polymer systems. Full article

In this work, we investigated the incorporation of a fluorescent side group, fluorescein octyl ester (FOE), in benzodithiophene-based donor–acceptor terpolymers as a strategy to modulate excited-state behavior. Three FOE-containing terpolymers (P2-iIa-c), obtained at different polymerization times, were systematically evaluated against an analogous material without the fluorescent pendant unit (P1-iI). Thermal analysis revealed good thermal stability and an increase in glass transition temperature upon FOE incorporation, suggesting restricted segmental mobility and increased conformational constraints within the conjugated backbone. Optical characterization showed distinct absorption spectra with reaction time and shorter fluorescence lifetimes for the FOE-containing materials, consistent with the presence of additional excited-state deactivation pathways and intramolecular energy transfer processes within the terpolymer backbone. An approximate estimation of energy transfer efficiencies (≈60–65%) suggested that such processes may be operative within the system. Cyclic voltammetry measurements showed only minor variations in HOMO and LUMO energy levels between P1-iI and P2-iIa-c series, indicating that the conjugated backbone predominantly determined the frontier orbital energies despite side chain modification. Furthermore, photocurrent measurements from the bilayer device configuration exhibited a systematic increase in photocurrent for the FOE-containing material, supporting the role of excitonic modulation, rather than significant changes in interfacial energetic alignment. These results suggest that fluorescent side chain incorporation provides an effective strategy for regulating exciton dynamics while maintaining the electronic structure of the donor–acceptor terpolymer. Full article

Benzodichalcogenophenes represent a valuable class of organic π-conjugated systems that have been investigated in a plethora of cutting-edge applications in the field of materials chemistry. Isomeric benzodifuran (BDF), benzodithiophene (BDT) and benzodiselenophene (BDS) analogs of phenanthrene, in which the two heteroaromatic rings are ortho-fused onto a benzene ring, represent convenient frameworks as functional materials in organic electronics. The orientation of the two condensed heteroaromatic rings with respect to the central benzene ring provides diverse structural isomers, which significantly differ in degrees of curvature, electronic and electrochemical properties. Furthermore, tailored modification and functionalization strategies enable fine-tuning of their intrinsic properties, leading to unique systems. This review offers a comprehensive overview of synthetic methodologies for constructing isomeric BDF, BDT and BDS skeletons, alongside an analysis of their electrochemical properties as influenced by the nature of heteroatoms. Finally, the most relevant applications of these systems, ranging from optoelectronics, supramolecular chemistry, and emerging biological studies, are discussed, providing valuable insights for future research direction. Full article

The current study represents a machine-learning (ML)-assisted reverse polymer engineering for the rational design of high-performance benzothiophene (BT) benzodithiophene (BDT) polymers for photodetector applications. By integrating their 5617 units with various acceptor moieties, a total of 72,976 unique polymer combinations are generated. The optical properties of these polymers are predicted with high accuracy (R² = 0.86) using a Gradient-Boosting Regression (GBR) model. The SHAP value-based feature importance analysis indicates that Chi0 is the most influential factor in predicting the absorption maxima (λ_max) of polymers, followed by LabuteASA, Chi0V, Chi1, SlogP_VSA12, and other molecular descriptors. The robustness of the employed model is further validated through K-Fold cross-validation, with the highest mean squared error (MSE) observed at 2.02 in the fold-2 subset. The designed polymers exhibit λ_max within the range of 400–750 nm, demonstrating their suitability for photodetector applications. Moreover, a Transformer-Assisted Orientation (TAO) approach is employed to optimize polymer design, successfully achieving bandgaps as low as 0.42 eV. This approach facilitates the rapid design and optimization of high-performance polymers with tailored electronic properties, effectively addressing the limitations of conventional trial-and-error methods. The current ML-assisted approach presents a promising strategy for expediting the development of high-performance photodetectors and other advanced optoelectronic devices. Full article

The synthesis of three biaryl systems containing the benzo[1,2-b:4,3-b’] framework was accomplished through the Suzuki–Miyaura cross-coupling reaction between 1-bromobenzo[1,2-b:4,3-b’]dithiophene and easily available polycyclic aromatic hydrocarbon boronic acid pinacol esters containing pyrene, fluorene, and fluorenone. The spectroscopic characterization of these molecules was carried out by means of NMR experiments and high-resolution mass spectrometry. UV-vis absorption measurements at different concentrations of the newly synthesized compounds were also performed. Full article

This study proposes a differential wavelength measurement method based on the electromagnetic-induced photoacoustic effect. The differential method involves irradiating the sample with multiple wavelengths and utilizing differences in absorption characteristics across different materials to calculate and measure the excitation light wavelengths. Compared to traditional detection methods, this approach combines the unique properties of electromagnetic-induced photoacoustic effect, offering high sensitivity and a wider detection range from microwave to light. Furthermore, the system is structurally simple and stable, suitable for non-destructive testing of various materials, including wavelength-sensitive biological tissues. The experimental results demonstrate that combined with Polymers Benzodithiophene Triazole–Quinoxaline (PBTQ) and Single-Walled Carbon Nanotubes (SWCNTs) as absorbing media, this technique provides a rapid and cost-effective means of wavelength measurement, achieving an uncertainty of approximately 2.33 nm within the range of 680–800 nm, and it can be used for wavelength/frequency measurement of various electromagnetic waves. Full article

Although much promising synthetic progress in conjugated polymer-based organic solar cells (OSCs) has resulted in significant improvement in power conversion efficiencies (PCEs) of from over 15 to >19.0% in the last five years, the sophisticated and complex reactions from at least two families’ monomers with remarkably different electron push–pull effects could still pose an unavoidable material burden for the commercialization of OSCs in the coming future. Therefore, the method of preparing a homopolymer from a sole monomer would significantly reduce the synthetic steps and costs in order to pave the way for the large-scale production of OSC materials. Therefore, alkylthio-thiophenyl-substituted benzo[1,2-b;4,5-b′]dithiophene (BDTTS) as the sole and key structural moiety with dihalogen and distannyl functional groups was designed and synthesized, respectively, in this study, for facile monomer syntheses and polymerizations to achieve three wide-bandgap homopolymer donors of BDTTS-alt-BDTT-Cl (P13), BDTTS-alt-BDTT (P15), and BDTTS (P14), respectively. The structural symmetry dependency on their physical, electrochemical, and optical properties, thin-film morphologies, and photovoltaic (PV) performance was investigated in detail. As a result, OSCs based on the asymmetric polymer P15, paired with BTP-eC9 as the electron acceptor, presented the best PV performance, with a PCE of 11.5%, a fill factor (FF) of 65.87%, and a short-circuit current (J_SC) of 22.04 mA·cm⁻², respectively. This PCE value is among the highest ones reported for BDT-type homopolymer donor-based OPVs, providing us with knowledge for obtaining promising PV performance from devices made of P15-like materials. Full article

Ladder polymers with poly(diketopyrrolopyrrole) (DPP) moieties have recently attracted enormous interest for a large variety of opto-electronic applications. Since the rigidity of the backbone increases with ladderization, a strong influence on the self-organization of thin films is expected. We study the molecular orientation of DPP-based ladder polymers in about 50 nm thin films using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS). Exemplarily, for one polymer, the orientation in thicker films is qualitatively investigated by infrared spectroscopy in transmission. Further, this method allows us to rule out the effects of a possible azimuthal ordering, which would affect the analysis of the orientation by PM-IRRAS. For all polymers, the long axis of the polymer backbone is preferentially oriented parallel to the substrate surface, pointing to a high degree of ordering. It is suggested that the choice of the side chains might be a promising way to tune for face-on and edge-on orientations. The exemplarily performed investigation of interface properties on substrates with different work functions suggests that the choice of the side chains has a minor effect on the interfacial electronic interface structure. Full article

Side chains play an important role in the photo-oxidation process of low band gap (LBG) polymers. For example, it has been shown that their photostability can be increased by the introduction of aromatic-oxy-alkyl links. We studied the photostability of prototypical LBG polymers with alkyl and oxyalkyl side chains during irradiation with white light (AM 1.5 conditions) in dry air using UV/vis and IR spectroscopy. Though its degradation kinetics were distinctly affected by the presence or absence of oxygen in the structure of the side chains, in particular cases, the stability was more affected by the presence of linear or branched side chains. Moreover, we showed that the exact position of the alkyl/oxyalkyl side chain at the polymer backbone could be crucial. Although minor effects of chemical modifications on the electronic parameters (ionization potential and gap) were observed, the molecular orientation, determined by polarization modulation-infrared reflection-absorption spectroscopy (PMIRRAS), could be affected. The aggregation and crystallinity of these polymers may distinctly affect their stability. Full article

Organic solar cells have obtained a prodigious amount of attention in photovoltaic research due to their unique features of light weight, low cost, eco-friendliness, and semitransparency. A rising trend in this field is the development of all-small-molecules organic solar cells (ASM-OSCs) due to their merits of excellent batch-to-batch reproducibility, well-defined structures, and simple purification. Among the numerous organic photovoltaic (OPV) materials, benzodithiophene (BDT)-based small molecules have come to the fore in achieving outstanding power conversion efficiency (PCE) and breaking the 17% efficiency barrier in single-junction OPV devices, indicating the significant potential of this class of materials in commercial photovoltaic applications. This review specially focuses on up-to-date information about improvements in BDT-based ASM-OSCs since 2011 and provides an outlook on the most significant challenges that remain in the field. We believe there will be more exciting BDT-based photovoltaic materials and devices developed in the near future. Full article

In recent years, donor-acceptor (D-A)-type conjugated polymers have been widely used in the field of organic solar cells (OSCs) and electrochromism (EC). Considering the poor solubility of D-A conjugated polymers, the solvents used in material processing and related device preparation are mostly toxic halogenated solvents, which have become the biggest obstacle to the future commercial process of the OSC and EC field. Herein, we designed and synthesized three novel D-A conjugated polymers, PBDT1-DTBF, PBDT2-DTBF, and PBDT3-DTBF, by introducing polar oligo (ethylene glycol) (OEG) side chains of different lengths in the donor unit benzodithiophene (BDT) as side chain modification. Studies on solubility, optics, electrochemical, photovoltaic and electrochromic properties are conducted, and the influence of the introduction of OEG side chains on its basic properties is also discussed. Studies on solubility and electrochromic properties show unusual trends that need further research. However, since PBDT-DTBF-class polymers and acceptor IT-4F failed to form proper morphology under the low-boiling point solvent THF solvent processing, the photovoltaic performance of prepared devices is not ideal. However, films with THF as processing solvent showed relatively desirable electrochromic properties and films cast from THF display higher CE than CB as the solvent. Therefore, this class of polymers has application feasibility for green solvent processing in the OSC and EC fields. The research provides an idea for the design of green solvent-processable polymer solar cell materials in the future and a meaningful exploration of the application of green solvents in the field of electrochromism. Full article

A series of medium bandgap polymer donors, named poly(1-(5-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)benzo [1,2-b:4,5-b′]dithiophen-2-yl)thiophen-2-yl)-5-((4,5-dihexylthiophen-2-yl)methylene)-3-(thiophen-2-yl)-4H-cyclopenta[c]thiophene-4,6(5H)-dione) (IND-T-BDTF), poly(1-(5-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)benzo [1,2-b:4,5-b′]dithiophen-2-yl)-4-hexylthiophen-2-yl)-5-((4,5-dihexylthiophen-2-yl)methylene)-3-(4-hexylthiophen-2-yl)-4H-cyclopenta[c]thiophene-4,6(5H)-dione (IND-HT-BDTF), and poly(1-(5-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)benzo [1,2-b:4,5-b′]dithiophen-2-yl)-6-octylthieno [3,2-b]thiophen-2-yl)-5-((4,5-dihexylthiophen-2-yl)methylene)-3-(6-octylthieno [3,2-b]thiophen-2-yl)-4H-cyclopenta[c]thiophene-4,6(5H)-dione (IND-OTT-BDTF), are developed for non-fullerene acceptors (NFAs) polymer solar cells (PSCs). Three polymers consist of donor-acceptor building block, where the electron-donating fluorinated benzodithiophene (BDTF) unit is linked to the electron-accepting 4H-cyclopenta[c]thiophene-4,6(5H)-dione (IND) derivative via thiophene (T) or thieno [3,2-b]thiopene (TT) bridges. The absorption range of the polymer donors based on IND in this study shows 400~800 nm, which complimenting the absorption of Y6BO (600~1000 nm). The PSC’s performances are also significantly impacted by the π-bridges. NFAs inverted type PSCs based on polymer donors and Y6BO acceptor are fabricated. The power conversion efficiency (PCE) of the device based on IND-OTT-BDTF reaches up to 11.69% among all polymers with a short circuit current of 26.37 mA/cm², an open circuit voltage of 0.79 V, and a fill factor of 56.2%, respectively. This study provides fundamental information on the invention of new polymer donors for NFA-based PSCs. Full article

Functional polymers featuring good processability in non-halogenated, benzene-free green solvents are highly desired due to health and environmental concerns. Herein, a series of novel D-A type conjugated polymers, PBDT-IIDs, are designed and successfully prepared by “green” functionalization of the polymers with highly hydrophilic, highly polar, highly flexible, and biocompatible oligoethylene glycol (OEG) side chains in order to improve the processability. These series polymers are named PBDT-IID2, PBDT-IID3, and PBDT-IID4, respectively, according to the number of oxygen atoms in the side chain. After confirmation by structural characterization, the basic properties of PBDT-IIDs are also investigated. With the increase in the OEG side chain length, the polymer PBDT-IID4 not only has good solubility in the halogen solvent chlorobenzene, but also exhibits excellent solubility in the green halogen-free solvent methyltetrahydrofuran (Me-THF). As a result, the green solvent Me-THF can also be applied to prepare PBDT-IIDs’ electrochromic active layers, except for chlorobenzene and toluene. The electrochromism of PBDT IIDs under both positive and negative voltages has a practical application potential. The several controllable switches between dark green and khaki (0–0.6 V) are expected to show great potential in the field of military camouflage. Furthermore, according to the principle of red, green, and blue (RGB) mixing, light blue-green in the reduced state (−1.6 V) can be used in the preparation of complementary ECDs to provide one of the three primary colors (green). Full article

Donor-acceptor conjugated polymers are considered advanced semiconductor materials for the development of thin-film electronics. One of the most attractive families of polymeric semiconductors in terms of photovoltaic applications are benzodithiophene-based polymers owing to their highly tunable electronic and physicochemical properties, and readily scalable production. In this work, we report the synthesis of three novel push–pull benzodithiophene-based polymers with different side chains and their investigation as hole transport materials (HTM) in perovskite solar cells (PSCs). It is shown that polymer P3 that contains triisopropylsilyl side groups exhibits better film-forming ability that, along with high hole mobilities, results in increased characteristics of PSCs. Encouraging a power conversion efficiency (PCE) of 17.4% was achieved for P3-based PSCs that outperformed the efficiency of devices based on P1, P2, and benchmark PTAA polymer. These findings feature the great potential of benzodithiophene-based conjugated polymers as dopant-free HTMs for the fabrication of efficient perovskite solar cells. Full article

The convenient and multigram synthesis of a linear benzo[b]dithiophene (BDT) structure is proposed (dimethyl 3,7-diamino-4,8-bis((2-methoxy-2-oxoethyl)thio)benzo[1,2-b:4,5-b’]dithiophene-2,6-dicarboxylate). The starting materials are commercially available 2,3,5,6-tetrachloroterephthalonitrile and methyl 2-mercaptoacetate, which undergo aromatic substitution, followed by a cyclization reaction in basic conditions to form suitable BDT for potential optoelectronic applications. Full article