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Dynamic Covalent Chemistry, consisting in the use of dynamic covalent bonds (DCBs) to create complex objects by working at the thermodynamic equilibrium, has undeniable advantages for the preparation of conjugated systems with tailored optoelectronic properties for organic electronics. Chemists can combine simple building blocks with simple functional groups of appropriate geometry, structure and stoichiometry to build multidimensional conjugated architectures. Dynamic covalent reactions are often precious metal‐free, generate little to no side products and are very efficient. DCBs however afford sensitive materials, and consequently a balance needs to be found between the ease of synthesis, the stability and the performances. The dynamicity of the target materials hence can considerably reduce their applicability in organic electronics where strongly stable materials are needed, but opens the door to stimuli‐responsive behaviour and recyclability. A way to overcome dynamicity issues is to lock DCBs, but often at the cost of decreased conjugation. In this review, we will highlight how DCBs are employed to prepare functional optoelectronically active materials, such as discrete molecules, polymers or covalent organic frameworks, applied in fields ranging from organic light‐emitting diodes and solar cells to organic batteries and transistors. We will also discuss their limitations, benefits and the current challenges to overcome. [ABSTRACT FROM AUTHOR]

Conjugated polymers (CPs) with low crystallinity are promising candidates for application in organic thermoelectrics (OTEs), particularly in flexible devices, because the disordered structures of these CPs can effectively accommodate dopants and ensure robust resistance to bending. However, n‐doped CPs usually exhibit poor thermoelectric performance, which hinders the development of high‐performance thermoelectric generators. Herein, we report an n‐type CP (ThDPP‐CNBTz) comprising two acceptor units: a thiophene‐flanked diketopyrrolopyrrole and a cyano‐functionalized benzothiadiazole. ThDPP‐CNBTz shows a low LUMO energy level of below −4.20 eV and features low crystallinity, enabling high doping efficiency. Moreover, the dual‐acceptor design enhances polaron delocalization, resulting in good thermoelectric performance. After n‐doping, ThDPP‐CNBTz exhibits an average electrical conductivity (σ) of 50.6 S cm−1 and a maximum power factor (PF) of 126.8 μW m−1 K−2, which is among the highest values reported for solution‐processed n‐type CPs to date. Additionally, a solution‐processed flexible OTE device based on doped ThDPP‐CNBTz exhibits a maximum PF of 70 μW m−1 K−2; the flexible device also shows remarkable resistance to bending strain, with only a marginal change in σ after 600 bending cycles. The findings presented in this work will advance the development of n‐type CPs for OTE devices, and flexible devices in particular. [ABSTRACT FROM AUTHOR]

Conjugated polymers (CPs) with low crystallinity are promising candidates for application in organic thermoelectrics (OTEs), particularly in flexible devices, because the disordered structures of these CPs can effectively accommodate dopants and ensure robust resistance to bending. However, n‐doped CPs usually exhibit poor thermoelectric performance, which hinders the development of high‐performance thermoelectric generators. Herein, we report an n‐type CP (ThDPP‐CNBTz) comprising two acceptor units: a thiophene‐flanked diketopyrrolopyrrole and a cyano‐functionalized benzothiadiazole. ThDPP‐CNBTz shows a low LUMO energy level of below −4.20 eV and features low crystallinity, enabling high doping efficiency. Moreover, the dual‐acceptor design enhances polaron delocalization, resulting in good thermoelectric performance. After n‐doping, ThDPP‐CNBTz exhibits an average electrical conductivity (σ) of 50.6 S cm−1 and a maximum power factor (PF) of 126.8 μW m−1 K−2, which is among the highest values reported for solution‐processed n‐type CPs to date. Additionally, a solution‐processed flexible OTE device based on doped ThDPP‐CNBTz exhibits a maximum PF of 70 μW m−1 K−2; the flexible device also shows remarkable resistance to bending strain, with only a marginal change in σ after 600 bending cycles. The findings presented in this work will advance the development of n‐type CPs for OTE devices, and flexible devices in particular. [ABSTRACT FROM AUTHOR]

Supramolecular electronics exploits the distinctive features stemming from noncovalent interactions, guiding the self‐assembly of molecules to craft materials endowed with customized electronic functionalities. Hydrogen‐bonded materials, characterized by their capacity to establish dynamic and stable networks, introduce an extra dimension to the development of supramolecular electronic systems. This study presents a comparative analysis of two remarkably small semiconductors utilizing diketopyrrolopyrrole functionalized with urea units as hydrogen‐bonding motifs, strategically positioned at opposing ends of the conjugated core. We show how the subtle distinction in functionalization not only influences morphology and self‐assembly dynamics via hydrogen‐bonding and π‐π stacking formation, but also holds significant consequences for ultimate charge transport properties. Our observations into the interplay of noncovalent interactions provide valuable insights and strategic pathways for the design of novel materials with enhanced electronic characteristics. [ABSTRACT FROM AUTHOR]

Molecular design is crucial for endowing conjugated polymers (CPs) with unique properties and enhanced electronic performance. Introducing Hydrogen‐bonding (H‐bonding) into CPs has been a broadly exploited, yet still emerging strategy capable of tuning a range of properties encompassing solubility, crystallinity, electronic properties, solid‐state morphology, and stability, as well as mechanical properties and self‐healing properties. Different H‐bonding groups can be utilized to tailor CPs properties based on the applications of interest. This review provides an overview of classes of H‐bonding CPs (assorted by the different H‐bond functional groups), the synthetic methods to introduce the corresponding H‐bond functional groups and the impact of H‐bonding in CPs on corresponding electronic and materials properties. Recent advances in addressing the trade‐off between electronic performance and mechanical durability are also highlighted. Furthermore, insights into future directions and prospects for H‐bonded CPs are discussed. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and characterization of a series of conjugated porous polymers (CPPs) based on a 2,4,6‐tris(5‐ethynylthiophen‐2‐yl)‐1,3,5‐triazine (TT) core moiety. TT was coupled with several conjugated building blocks as comonomers, including naphthodithiophene, benzodithiophene, bithiophene, tetraphenyl porphyrin, azulene, and perylene diimide, utilizing the Sonogashira‐coupling reaction to produce narrow band gap (1.73–2.19 eV) CPPs. The solid‐state UV‐visible spectra demonstrated broad absorption in 350 nm to 900 nm region, indicating extended π‐conjugation in the polymers. The photophysical properties of the polymers have been tuned by the judicious choice of comonomer. The obtained CPPs exhibit excellent thermal stability, reaching as high as 500 °C, and porosity insights reveal dominance of mesopores and macropores. Morphological studies reveal that 2‐ethylhexyl substituted perylene diimide hinder the stacking amongst the polymeric backbone, resulting in featureless aggregates, whereas the cyclohexyl group on perylene diimide results in well‐defined nanofibrous morphology. These narrow band‐gap CPPs hold promise for applications in energy storage, organic electronics, photocatalysis and sensing technologies. [ABSTRACT FROM AUTHOR]

Oligomers and polymers consisting of multiple thiophenes are widely used in organic electronics such as organic transistors and sensors because of their strong electron-donating ability. In this study, a solution to the problem of the poor solubility of polythiophene systems was developed. A novel π-conjugated polymer material, PDPP-5Th, was synthesized by adding the electron acceptor unit, DPP, to the polythiophene system with a long alkyl side chain, which facilitated the solution processing of the material for the preparation of devices. Meanwhile, the presence of the multicarbonyl groups within the DPP molecule facilitated donor–acceptor interactions in the internal chain, which further improved the hole-transport properties of the polythiophene-based material. The weak forces present within the molecules that promoted structural coplanarity were analyzed using theoretical simulations. Furthermore, the grazing incidence wide-angle X-ray scanning (GIWAXS) results indicated that PDPP-5Th features high crystallinity, which is favorable for efficient carrier migration within and between polymer chains. The material showed hole transport properties as high as 0.44 cm2 V−1 s−1 in conductivity testing. Our investigations demonstrate the great potential of this polymer material in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

Polythiophene, as a class of potential electron donor units, is widely used in organic electronics such as transistors. In this work, a novel polymeric material, PDPPTT-FT, was prepared by incorporating the electron acceptor unit into the polythiophene system. The incorporation of the DPP molecule assists in improving the solubility of the material and provides a convenient method for the preparation of field effect transistors via subsequent solution processing. The introduction of fluorine atoms forms a good intramolecular conformational lock, and theoretical calculations show that the structure displays excellent co-planarity and regularity. Grazing incidence wide-angle X-ray (GIWAXS) results indicate that the PDPPTT-FT is highly crystalline, which facilitates carrier migration within and between polymer chains. The hole mobility of this π-conjugated material is as high as 0.30 cm2 V−1 s−1 in organic transistor measurements, demonstrating the great potential of this polymer material in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

Non‐conjugated pendant electroactive polymers (NCPEPs) are an emerging class of polymers that offer the potential of combining the desirable optoelectronic properties of conjugated polymers with the superior synthetic methodologies and stability of traditional non‐conjugated polymers. Despite an increasing number of studies focused on NCPEPs, particularly on understanding fundamental structure‐property relationships, no attempts have been made to provide an overview on established relationships to date. This review showcases selected reports on NCPEP homopolymers and copolymers that demonstrate how optical, electronic, and physical properties of the polymers are affected by tuning of key structural variables such as the chemical structure of the polymer backbone, molecular weight, tacticity, spacer length, the nature of the pendant group, and in the case of copolymers the ratios between different comonomers and between individual polymer blocks. Correlation of structural features with improved π‐stacking and enhanced charge carrier mobility serve as the primary figures of merit in evaluating impact on NCPEP properties. While this review is not intended to serve as a comprehensive summary of all reports on tuning of structural parameters in NCPEPs, it highlights relevant established structure‐property relationships that can serve as a guideline for more targeted design of novel NCPEPs in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Six polymers based on thiazolothiazole via metal-free reaction are synthesized. • Organic semiconductors are developed via eco-friendly and low-cost methods. • Promising efficiency of 15.3% is obtained in perovskite solar cells. The design of conjugated polymers with advanced properties is a significant task for the development of organic electronics. At the same time, it is important to pay attention to the methods of their synthesis, excluding toxic and expensive reagents, following the trends in sustainability. In this study, six thiazolothiazole-based conjugated polymers with thiophene, fluorene, phenylene, and benzodithiophene moieties were synthesized and thoroughly characterized. All materials were obtained through a non-catalyzed condensation reaction of carbonyl derivatives with rubeanic acid under ambient conditions. It is shown that the optoelectronic and electrophysical properties of polymers are suitable for their application in organic or hybrid electronic devices. The certain polymers are found to be promising hole-transport interlayer materials in perovskite solar cells, thus featuring the great potential of proposed methods of development of organic semiconductors. [ABSTRACT FROM AUTHOR]

• The exploration of internal OLED device structure and its working mechanism with significance of various layers of OLEDs. • A comprehensive discussion processible conjugated polymeric nanocomposite materials exhibit marked electrical and optical properties towards the interest for OLEDs applications. • The application of such polymeric nanocomposite materials is discussed with their success and failure towards their optical and electrical properties in making OLEDs. • Efficient fabrication techniques for high performance OLEDs. Organic light-emitting diodes (OLEDs) are one of the leading, promising technologies for eco-friendly lighting sources and vivid color display panels owing to their low operating voltage, fast switching, wide viewing angle, lightweight flexibility, etc. This review reports the various synthesis techniques for optimizing the OLED device performance using polymeric nanocomposites, which provide lighting and display. The internal OLED device structure and its working mechanism have also been reviewed. Some of the processible conjugated polymeric nanocomposite materials exhibit unique electrical and optical properties that are of interest for OLEDs applications. Nanoparticles with conjugated polymer matrix make polymer nanocomposite, and that composite is used as an active layer between the structures of optoelectronic devices like OLEDs. The application of such polymeric nanocomposite materials is discussed, as well as their success and failure regarding their optical and electrical properties in making OLEDs. Various OLED device fabrication technologies have been reported. The quantum leap of solid-state flexible and rollable lighting and display devices as of OLED applications is also discussed. The exploration encompasses various aspects, including synthesis methods, internal device structures, working mechanisms, and the fabrication technologies involved in OLEDs. The insights obtained will contribute to the advancement of sustainable lighting and display technologies, fostering innovation in the field of organic electronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • The organic semiconductor film is not uniform along the perpendicular direction. • The inhomogeneity of the film affects the mobility at different film-depth positions. • An approach was presented to study the mobilities at different film-depth positions. • The structure–property relations at different positions of the film were established. Carrier mobility is a crucial parameter characterizing the performance of organic semiconductors in thin film optoelectronic devices. The organic semiconductor film is usually not uniform along the film-perpendicular direction. This non-uniformity affects the carrier mobility at various depths within the film, thereby influencing device performance. Conventional methods for measuring mobility are basically not available to determine film-depth-dependent charge density or mobility. In this study, an easily accessed approach was proposed to investigate the film-depth-dependent electronic properties. Soft plasma etching was introduced to achieve incremental etching of the film, without causing damage to the underlying sublayers. For doped films with intrinsic charge, film-depth-dependent charge density, and film-depth-dependent mobility were extracted from the transfer characteristics evolution during the etching. For materials without intrinsic charge, film-depth-dependences of mobility could also be estimated under light illumination. The proposed method achieves a film-depth resolution of approximately 10 nm. It is revealed that for some model conjugated polymers, the mobility at the top surface is one order higher than that at the buried region of the transistor. This feature leads to unfavorable field-effect mobility. This work provides insights into the film-depth-dependent electronic properties and a strategy to optimize the electronic device performance. [ABSTRACT FROM AUTHOR]

Polymeric semiconductors based on donor-acceptor (D-A) conjugated polymers have emerged as a promising class of materials for various applications due to their excellent solution processability, low cost, and intrinsic flexibility. The use of the indacenodithiophene (IDT) unit as a building block has received significant attention due to its unique pentacyclic ring structure and exceptional photophysical and electronic properties. This review focuses on the latest progress in the field of IDT-based polymers. We discuss the versatility of IDT as a structural molecular engineering tool, along with the use of various electron-deficient acceptors as comonomers and modifications to the IDT structure unit. These advancements have led to improved device performance, particularly in organic electronics applications such as photodetectors, solar cells, field-effect transistors, and thermoelectric devices. In summary, this review serves as a valuable reference for researchers who are interested in creating high-performance polymeric semiconductors using the IDT building block for a range of optoelectronic devices. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A metal-catalyst-free route to synthesize electrochromic CMP (E-CMP) is demonstrated. • The utilized method parallelly generates powder and film analogs of E-CMP. • The computational analysis suggests the formation of a 2D E-CMP framework. • The E-CMP registered a high coloration efficiency of ∼147 cm2/C at 650 nm. • The utilized E-CMP framework shows rich optical-memory features. Conjugated microporous polymers (CMPs) have gained rampant interest due to their remarkably well-suited features for organic electronics. However, little attention has been paid to the development of electrochromic CMPs (E-CMPs). To date, the synthesis of E-CMPs has only been reported through metal catalyst-based routes. Further, the inability of the reported routes to concurrently produce powder analogs (say, two-in-one approach) of the films has utterly restricted E-CMP's utilization in tools (such as adsorption analyzers and TEM) widely employed for the investigation of microporous nature. Due to this limitation, while successful synthesis of E-CMPs has been claimed in reports, the confirmation of their microporous nature still appears to be side-lined. Herein, we report a memory-rich conjugated microporous polymer-based electrochromic framework (denoted as E-CMP-Sb1) through a two-in-one metal-catalyst free route. The synthesized E-CMP-Sb1 film demonstrated good optical tunability in visible and NIR regions and registered a coloration efficiency of ∼147 cm2/C at 650 nm. The synthesized E-CMP-Sb1 was deployed in a gel-polymer electrolyte-based electrochromic device (ECD) to mark the first inching effort toward the still-unexplored field of E-CMP-based ECDs. Probing E-CMP's performance in real ECDs is expected to elucidate their commercial suitability in the years to come. This work provides a versatile platform for the existing synthesis and characterization issues of E-CMPs. Parallelly, the study also introduces a new material in the electrochromic fraternity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Six D-A conjugated polymers synthesized successfully in a continuous flow reactor. • Obtained high degree of polymerization (31 – 88) and excellent reproducibility. • High quality polymers synthesized using a single set of reaction parameters. • Flow synthesis as an ideal method to produce D-A conjugated polymers. Donor-acceptor (D-A) conjugated polymers often exhibit excellent performance in electronic and photonic applications, however, their synthesis remains a hurdle to achieving their wide-spread commercialization. While scalable and reproducible flow syntheses have emerged as promising candidates to address this issue, they have only been applied to a narrow scope of polymer types. In this study, we explore the synthesis of six different D-A conjugated polymers in a continuous flow reactor to determine how reaction and polymer parameters influence the degree of polymerization (DP) and quality of the resulting polymers. We found that we could successfully synthesize p -type, n -type, and ambipolar D-A conjugated polymers with a single set of reaction parameters. Only the reaction time required optimization to achieve high-DPs. Importantly, we found that we could achieve comparable DPs to batch reactions, but with higher yields and much shorter reaction times. High-quality polymers were also obtained, which was confirmed with optical and electrochemical properties measurements and by their performance in organic field-effect transistors. We expect this work to further establish flow synthesis as an ideal method to make D-A conjugated polymers, which may help facilitate their commercialization in high-performing organic devices. [ABSTRACT FROM AUTHOR]