One of the primary drawbacks of organic materials, compared to their inorganic counterparts in various optoelectronic applications, is their lower charge generation efficiency, which stems from their inherently higher exciton binding energy. Therefore, new out-of-the-box approaches need to be introduced to the field. Herein, we propose a new approach to increase the charge formation of naphthalenediimide (NDI) derivatives by inducing a large torsional angle between the NDI core and the core-attached substituent, deconjugating the resulting extended π-system. To study the extent of this change, transient absorption spectroscopy characterisation has been performed on a set of derivatised NDI molecules where the core-attached substituents have been systematically altered to modulate the resulting torsional angle. The data indicates an enhanced charge generation with core-attached substituents from phenyl to anthracenyl which increase in both size and degree of rotational inhibition. State-of-the-art excited state simulations using the TD-B3LYP/def2-SVP level of theory were performed to calculate absorption spectra and to parametrise potential energy surfaces to run non-adiabatic quantum dynamics simulations for the two extreme NDI systems, showing crucial differences due to the influence of charge transfer states. This opens the possibility for a new family of NDI molecules with implications for a wide range of applications such as photovoltaics, transistors and catalysis.

PurposeThe study conducts a comparative analysis between two prominent methods for fabricating composites for bone scaffolds—the (solid) solvent method and the solvent-free (melting) method. While previous research has explored these methods individually, this study provides a direct comparison of their outcomes in terms of physicochemical properties, cytocompatibility, and mechanical strength. We also analyse their workflow and scalability potentials.Design/methodology/approachPolycaprolactone (PCL) and hydroxyapatite (HA) composites were prepared using solvent (chloroform) and melting (180°C) methods, then 3D-printed using an extrusion-based 3D printer to fabricate scaffolds (8 × 8 × 4 mm). Rheology, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), accelerated degradation, mechanical/compression test, wettability/contact angle, live/dead assay, and DNA quantification (Picogreen) assays were evaluated.FindingsThe study finds that scaffolds made via the solid solvent method have higher mechanical strength and degradation rate as compared to those from the melting method, while both methods ensure adequate cytocompatibility and homogenous hydroxyapatite distribution, supporting their use in bone tissue engineering.OriginalityThis research investigates the utility of chloroform as a solvent for PCL composite in a direct comparison with the melting method. It also highlights the differences in workflows between the two methods and their scalability implications, emphasizing the importance of considering workflow efficiency and the potential for automation in scaffold fabrication processes for bone tissue engineering applications.

Aligning the material properties of organic semiconducting polymers to effectively interface with biological matter is critical for their use in bioelectronic devices. Synthetic modification and advanced processing techniques have typically been employed to promote cell adhesion and growth. In this study we apply UV-Ozone (UVO) treatment as a simple and accessible alternative for modifying pDPP3T films. Exposure to UVO increases polarity of the semiconductor surface, as confirmed by contact angle and XPS analysis. Surface treatment at and above the optimized time (t ≥ 30 s) consequently led to enhanced Schwann cell growth, with comparable behaviour to standard tissue culture plastic (TCP). Simultaneously, prolonged exposure begins to cause significant changes to the polymer's optical properties, with gradual photobleaching leading to the reduction in semiconducting behavior above 30 s. Leveraging the optimal biointerfacing properties of the UVO-treated pDPP3T, the validity of the technique in supporting cell viability and proliferation upon a semiconducting polymer was tested using electrical impedance spectroscopy. This work demonstrates the potential to more easily integrate conjugated polymers with biological environments, widening the opportunity to explore the interplay between ion diffusion and semiconductor electroactivity in the presence of biological cells.

As an effective tool to monitor the glucose level in the human body and to diagnose diabetes, glucose sensors are widely applied in medical practice and the daily life of patients. Cupric oxide (CuO) is a promising material for fabricating non-enzymatic glucose sensors. While CuO shows very good sensing performance and is easy to synthesise, the common wet chemical routes can result in varying nanostructures depending on various parameters, including temperature and pH. The present work explores the influence of the solution pH and base/acid addition order on the physico-chemical characteristics and sensing behaviour of CuO formed following a simple solution synthesis route. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman and IR spectroscopy were used to characterise the nanostructures. Although the synthesis route is robust with respect to the acid/base concentration, it is clear that an overall alkaline environment is needed for the successful formation of CuO nanostructures.

Achieving spectrally selective organic photodetectors (OPDs) without using broadband-absorbing semiconductors with input filtering is a strenuous challenge. Charge collection narrowing (CCN) is a promising strategy to obtain spectrally selective near-infrared (NIR) OPD by adopting a thick bulk heterojunction (BHJ) as active layers. In this work, a random terpolymer comprised from a diketopyrrolopyrrole (DPP), thiophene (T) and benzothiadiazole (BT), ranDPP-2TBT, is prepared and used as a donor material in combination with the low bandgap non-fullerene acceptor (NFA) IEICO-4F. OPDs with a low dark current density (6.88 x 10-9 A cm-2) and a 68 nm full-width-at-half-maximum (FWHM) narrowband response (R = 0.13 A W-1 at 916 nm) in the near-infrared are achieved. Finally, an application of the OPD as a biometric heart-rate sensor via photoplethysmography for real-time monitoring is demonstrated.

Organic semiconducting polymers blended into elastomeric materials has shown to be a successful method for improving flexibility designed for wearable electronics. One such elastomer that has not been readily explored in combination with an organic semiconducting polymer is polyborosiloxane (PBS). PBS shows remarkable viscoelastomeric properties, due to the borate ester groups that crosslink the siloxane backbones, demonstrating a dynamic covalent crosslinking mechanism. The detailed study presented here showcases the properties of two different PBS elastomers and the effect of blending a well-known organic semiconducting polymer, poly(3-hexylthiophene) (P3HT). Compatibility studies find that one elastomer blends more favourably than the other due to differences in the crosslinking density leading to the formation of P3HT crystallites within the blend. The viscoelastic properties of the PBS:P3HT blends are studied through detailed rheological experiments and the relaxation processes are discussed.

Nako Nakatsuka opened the discussion of the introductory Spiers Memorial Lecture by Luisa Torsi: I was wondering about the mechanism of how large-scale transistors can detect single molecules, Professor Torsi mentioned a domino effect for the amplification of the single molecule binding event t

Poly(nickel-benzene-1,2,4,5-tetrakis(thiolate)) (Ni-btt), an organometallic coordination polymer (OMCP) characterized by the coordination between benzene-1,2,4,5-tetrakis(thiolate) (btt) and Ni2+ ions, has been recognized as a promising p-type thermoelectric material. In this study, we employed a constitutional isomer based on benzene-1,2,3,4-tetrakis(thiolate) (ibtt) to generate the corresponding isomeric polymer, poly(nickel-benzene-1,2,3,4-tetrakis(thiolate)) (Ni-ibtt). Comparative analysis of Ni-ibtt and Ni-btt reveals several common infrared (IR) and Raman features attributed to their similar square-planar nickel-sulfur (Ni-S) coordination. Nevertheless, these two polymer isomers exhibit substantially different backbone geometries. Ni-btt possesses a linear backbone, whereas Ni-ibtt exhibits a more undulating, zig-zag-like structure. Consequently, Ni-ibtt demonstrates slightly higher solubility and an increased bandgap in comparison to Ni-btt. The most noteworthy dissimilarity, however, manifests in their thermoelectric properties. While Ni-btt exhibits p-type behavior, Ni-ibtt demonstrates n-type carrier characteristics. This intriguing divergence prompted further investigation into the influence of OMCP backbone geometry on the electronic structure and, particularly, the thermoelectric properties of these materials.

Electrical stimulation has shown promise in clinical studies to treat nerve injuries. This work aimed to create an aligned bioelectronic construct that can be used to bridge a nerve gap, directly interfacing with the damaged nerve tissue to support regeneration. The conductive three-dimensional bioelectronic scaffolds described herein are composite materials, comprised of conductive polypyrrole (PPy) nanoparticles embedded in an aligned collagen hydrogel. The bioelectronic constructs were seeded with dorsal root ganglion (DRG) derived primary rat neurons and electrically stimulated in vitro. The PPy loaded constructs supported a 1.7-fold increase in neurite length in comparison to control collagen constructs. Furthermore, upon electrical stimulation of the PPy-collagen construct, a 1.8-fold increase in neurite length was shown. This work illustrates the potential of bioelectronic constructs in neural tissue engineering and lays the groundwork for the development of novel bioelectronic materials for neural interfacing applications.

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has gained significant popularity as a material in both academic and industrial fields, especially due to the its vast application in electronic-based devices. However, despite its popularity and prominence in organic electronics, there is still a lack of scientific references regarding the synthesis and production of PEDOT:PSS inks. Here, we aim to discuss and elucidate the relationship between the conducting properties of PEDOT:PSS inks and the oxidizing agent concentration used during the oxidative polymerization of EDOT in the presence of PSS. To achieve this, we first studied the effect of addition of an oxidant to PSS solutions via dynamic light scattering (DLS) to characterize whether a higher oxidant concentration impacts the chain conformation of PSS in solution. Furthermore, we conducted UV-Vis spectroscopy measurements at various stages during the synthesis and purification of PEDOT:PSS to assess the formation of polarons and bipolarons. Finally, we evaluated the properties of deposited PEDOT:PSS films. Our findings demonstrate that the addition of an oxidant to PSS solutions leads to polyelectrolyte chain shrinkage, due to the screening of electrostatic interactions between the negatively charged sulfonate groups. Consequently, the likelihood of effective coupling between the PEDOT+ and PSS- counterparts is reduced due to the presence oxidant ions. This hypothesis was confirmed since inks polymerized with a higher oxidant concentration underwent depletion from bipolarons to polarons during the purification process as counterions originating from the oxidizing agent were removed. We demonstrate that oxidant agent ions, required for PEDOT:PSS synthesis, affect the PSS chain conformation and the final properties of the ink.

Efficient treatment of wastewater contaminated with carcinogenic Cr(VI) has been a long-term challenge for both academic and industrial research efforts. Removal of Cr(VI) species by ion exchange is a relatively simple and efficient method, and its combination with highly tailorable nanomaterials is promising for the treatment of such wastewater. Here, we report a type of cationic porous organic polymer (POP), namely, PTPA-PIP, which can be prepared simply by converting the corresponding aromatic polyamine PTPA to its protonated form, thereby significantly increasing its hydrophilicity and ability to disperse homogeneously in water, crucial for application in water treatment. In addition to detailed characterization of the physicochemical properties of PTPA-PIP (including using Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and solid-state NMR techniques), adsorption experiments demonstrate that PTPA-PIP removes low-concentration dichromate anions with very high performance, including excellent exchange capacity (maximum capacity of 230 mg Cr

Efficient treatment of wastewater contaminated with carcinogenic Cr(VI) has been a long-term challenge for both academic and industrial research efforts. Removal of Cr(VI) species by ion exchange is a relatively simple and efficient method, and its combination with highly tailorable nanomaterials is promising for the treatment of such wastewater. Here, we report a type of cationic porous organic polymer (POP), namely, PTPA-PIP, which can be prepared simply by converting the corresponding aromatic polyamine PTPA to its protonated form, thereby significantly increasing its hydrophilicity and ability to disperse homogeneously in water, crucial for application in water treatment. In addition to detailed characterization of the physicochemical properties of PTPA-PIP (including using Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and solid-state NMR techniques), adsorption experiments demonstrate that PTPA-PIP removes low-concentration dichromate anions with very high performance, including excellent exchange capacity (maximum capacity of 230 mg Cr2O72-/g PTPA-PIP), ultrafast removal (initial adsorption rate of 83 mg g(-1) min(-1)), excellent selectivity (similar to 10% loss of adsorption capacity in the presence of 40-fold concentration of competing anions), as well as superior reusability (reusable for at least 5 cycles without compromised performance). These results demonstrate that PTPA-PIP is an outstanding candidate for application in industrial settings for the effective removal of harmful Cr(VI) pollutants in wastewater.

Conjugated polymers with hydrogen bonds enable self-healing and stretchability in wearable electronics. This review highlights recent advances, focusing on mechanical properties to guide design, and examines current trends in material properties.

Intrinsically conducting diketopyrrolopyrrole (DPP) compounds functionalised with pendant quaternary ammonium groups have been synthesised. The hydroxide forms were found to be the product of base hydrolysis of the DPP amide during synthesis, likely made possible by restricted resonance. This gave mixed chemical compositions of solutions and conductive films formed by drop -casting. Chemical decomposition of the hydrolysed compounds was also observed at temperatures above 85 degrees C. Conductivities of approximately 3 x 10 -4 S m - 1 were observed in processed films of DPP ammonium hydroxides. It was also found that trifluoroacetic acid (TFA) DPP precursors gave clear electron paramagnetic resonance (EPR) signals indicative of doping and exhibited conductivities one order of magnitude larger than the hydroxides. This opens the possibility of using ammonium TFAs as moieties for doping organic semiconductors.

Yuya Tanaka opened a discussion of the paper by Xugang Guo: Can you systematically optimise the properties and efficiency of transition-metal-catalysed doping? Xugang Guo answered: Sure, this is in fact a very nice suggestion! In fact, there are many research efforts going on in our lab these days to systematical

Recent progress in the research of n -type materials for organic thermoelectrics has drawn the attention to the metal coordination polymer poly(nickel-ethylenetetrathiolate) (poly(Ni-ett)). These polymers have excellent stability in air because their backbone structure is composed of air -stable ligands and exhibit good electronic properties when pressed into pellets or grown into crystals. However, due to their brittle nature and limited solubility, they are often blended with solution processable but electrically insulating polymers to produce composite films. Herein, we demonstrate the possibility of exploiting the 3D structuring ability of a polymer scaffolding matrix (based on polyvinylidene fluoride (PVDF)) to fabricate porous bulk structures. Porosity is introduced to reduce the lattice contribution to the thermal conductivity and used as a lever to increase the thermoelectric efficiency of the composite aerogel poly(Ni-ett): PVDF. For practical applications, these materials have great potential for vertical thermoelectric generators, as the low thermal conductivity and millimetre -thick samples would allow a thermal gradient to be maintained across it (without actively cooling one side, as in the case of certain thin-film technologies). In this manuscript, we present an original approach for the fabrication of novel n -type polymer aerogels resulting in lightweight and bulk size thermoelectric materials. The composite aerogels exhibit a low thermal conductivity of 52 mW m-1 K-1, and their figure of merit zT is comparable to the dense neat pellet with reasonable stability over six months.

Joseph Cameron opened discussion of the paper by Kunio Awaga: Would there be any advantage to increasing the dielectric constant of the semiconductor layer in MISM or MISIM devices? Kunio Awaga replied: The photocurrent density in the MISM and MISIM cells significantly increases

Wataru Ishii opened discussion of the paper by Jenny Clark: What type of defect is required to induce the coherent singlet fission (SF)? I am curious about the distance between and orientation of the rubrene molecules in the dimer. Jenny Clark responded: It is not yet clear what kind of defect is required to indu

Heat is an inexhaustible source of energy, and it can be exploited by thermoelectronics to produce electrical power or electrical responses. The search for a low-cost thermoelectric material that could achieve high efficiencies and can also be straightforwardly scalable has turned significant attention to the halide perovskite family. Here, we report the thermal voltage response of bismuth-based perovskite derivates and suggest a path to increase the electrical conductivity by applying chalcogenide doping. The films were produced by drop-casting or spin coating, and sulfur was introduced in the precursor solution using bismuth triethylxanthate. The physical-chemical analysis confirms the substitution. The sulfur introduction caused resistivity reduction by 2 orders of magnitude, and the thermal voltage exceeded 40 mV K-1 near 300 K in doped and undoped bismuth-based perovskite derivates. X-ray diffraction, Raman spectroscopy, and grazing-incidence wide-angle X-ray scattering were employed to confirm the structure. X-ray photoelectron spectroscopy, elemental analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were employed to study the composition and morphology of the produced thin films. UV-visible absorbance, photoluminescence, inverse photoemission, and ultraviolet photoelectron spectroscopies have been used to investigate the energy band gap.

Bismuth based coordination complexes are advantageous over other metal complexes, as Bismuth is the heaviest non-toxic element with high spin orbit coupling and potential optoelectronics applications. Herein, four Bismuth halide-based coordination complexes [Bi2Cl6(phen-thio)2] (1), [Bi2Br6(phen-thio)2] (2), [Bi2I6(phen-thio)2] (3), and [Bi2I6(phen-Me)2] (4) were synthesized, characterized and subjected to detailed photophysical studies. The complexes were characterized by single crystal X-ray diffraction, powder X-ray diffraction and NMR studies. Spectroscopic analysis of 1-4 in solutions of different polarities were performed to understand the role of organic and inorganic components in determining the ground and excited state properties of the complexes. The photophysical properties of the complexes were characterized by ground state absorption, steady state photoluminescence, microsecond time-resolved photoluminescence and absorption spectroscopy. Periodic Density Functional Theory (DFT) calculations were performed on the solid state structures to understand the role of organic and inorganic part of the complexes. The studies showed that changing the ancillary ligand from chlorine (Cl), bromine (Br) to iodine (I) bathochromically shifts the absorption band along with enhancing the absorption coefficient. Also, changing the halides (Cl, Br to I) affect the photoluminescent quantum yields of the ligand centered (LC) emissive state without markedly affecting the lifetimes. The combined results confirmed that ground state properties are strongly influenced by the inorganic part and the lower energy excited state is LC. This study paves the way to design novel bismuth coordination complexes for optoelectronic applications by rigorously choosing the ligands and bismuth salt.