Search Results (78)

Almond skin (AS) from industrial almond peeling is considered an agri-food waste with adequate composition to obtain composite films for food packaging due to its richness in polysaccharides, proteins, and phenolic compounds. Composite films based on amorphous polylactic acid (PLA) or partially acetylated polyvinilalcohol (PVA) were obtained by melt blending and compression moulding, incorporating different ratios of defatted AS powder (0, 5, 10, and 15 wt.%). The filler was better integrated in the polar PVA matrix, where more interactions were detected with the filler compounds, affecting glass transition and crystallization of the polymer. The AS particles provided the films with the characteristic colour of the powder and strong UV light-blocking effect, while improving the oxygen barrier capacity of both polymeric matrices (24% in PLA with 15% AS and 42% in PVA with 10% AS). The water vapour permeability increased in PLA (by 192% at 15% AS), but decreased in PVA films, especially with low AS content (by 19% with 5% particles). The filler also provided the PLA and PVA films with antioxidant properties due to its phenolic richness, improving the oxygen barrier capacity of the materials and delaying the unsaturated oil oxidation. This was reflected in the lower peroxide and conjugated dienes and trienes values of the sunflower oil packaged in single-dose bags of the different materials. The high oxygen barrier capacity of the PVA bags mainly controlled the preservation of the oil, which made the effect of the antioxidant AS powder less noticeable. Full article

Partially substituting other proteins in soy-protein-based products is an effective method to meet nutritional and application requirements. However, the emulsifying properties of soybean protein isolates (SPI) when partially substituted with zein hydrolysates (ZH) remain unknown. In the present work, protein blend (0 h-SPI/ZH) from SPI and ZH with a ratio of 3.5: 1 (w/w) was treated by transglutaminase (TGase) for 0, 0.5, 1.0, and 1.5 h, respectively. SDS-PAGE analysis results indicate protein polymers were generated in SPI/ZH conjugates. Emulsifying activity of the conjugates (1.5 h-SPI/ZH) was significantly increased from 23.69 to 28.13 m² g⁻¹ in comparison with SPI, and there was no statistically significant difference (p < 0.05) in emulsion stability. The apparent viscosity, surface hydrophobicity of the SPI/ZH conjugates were significantly increased. Emulsion droplet size and zeta potential stabilized by 1.5 h-SPI/ZH were also increased; the values were 64.73 to 80.79 r.nm and −21.8 to −29.9 mV, respectively. CLSM results indicate that 1.5 h-SPI/ZH conjugates stabilized the emulsion and had a thicker adsorption layer. Overall, high values of negative zeta potential and suitable molecular weight distribution of the SPI/ZH conjugates might be responsible for the improved emulsifying property. This study provides insights for the preparation of soy-protein-based products as a promising food emulsifier. Full article

This review examines the distinct advantages of organic semiconductors over conventional insulating polymers as optically active materials in photonic applications. We analyze the fundamental principles governing their unique optical and electronic properties, from basic conjugated polymer systems to advanced molecular architectures. The review systematically explores key material classes, including polyfluorenes, polyphenylene vinylenes, and polythiophenes, highlighting their dual electrical–optical functionality unavailable in passive polymer systems. Particular attention is given to polymer blends, composites, and hybrid organic–inorganic systems, demonstrating how semiconductor properties enable enhanced performance through materials engineering. We contrast passive components with active photonic devices, illustrating how the semiconductor nature of these polymers facilitates novel functionalities beyond simple light guiding. The review explores emerging applications in neuromorphic photonics, quantum systems, and bio-integrated devices, where the combined electronic–optical properties of organic semiconductors create unique capabilities impossible with insulating polymers. Finally, we discuss design strategies for optimizing these distinctive properties and present perspectives on future developments. This review establishes organic semiconductors as transformative materials for advancing photonic technologies through their combined electronic–optical functionality. Full article

Background/Objectives: Non-viral vectors have gained recognition for their ability to enhance the safety of gene delivery processes. Among these, polyethyleneimine (PEI) stands out as the most widely utilized cationic polymer due to its accessibility. Traditional methods of modifying PEI, such as ligand conjugation, chemical derivatization, and cross-linking, are associated with intricate preparation procedures, limited transfection efficiency, and suboptimal biocompatibility. Methods: In this investigation, enhanced transfection efficiency was achieved through the straightforward physical blending of PEI carriers with spermine. Results: Transfection assays explored the maximal enhancement potential conferred by spermine, alongside further methodological refinements aimed at optimizing transfection efficacy, showcasing a potential increase of up to 40.7%. Through the comparison of different addition sequences of spermine, the optimal complex PEI/Spermine/DNA for transfection efficiency was selected. Characterization of PEI/Spermine/DNA revealed that, compared to PEI/DNA, its particle size increased to approximately 150 nm. Molecular dynamics simulation results revealed that spermine can enhance the interaction between PEI and DNA, thereby forming a system with lower energy and greater stability. Mechanistic inquiries studies also disclosed that spermine augments the endosomal escape capability of PEI carriers without altering pathways involved in the cellular uptake of gene nanoparticles, thereby facilitating heightened gene expression. Conclusions: PEI-Sper emerges as a promising non-viral vector for gene delivery, distinguished by its simplicity in preparation, cost-effectiveness, and superior transfection efficiency. Full article

The ternary blending strategy is a fundamental approach that is widely recognized in the field of organic optoelectronics. In our investigation, leveraging the inherent advantages of the ternary component blending methodology, we introduced an innovative design for organic photodetectors (OPDs) aimed at reducing the dark current density (J_d) under reverse bias. This pioneering effort involved combining two distinct conjugated molecules (IT-4F and IEICO-4F) with a conjugated polymer (PM7), resulting in a composite material characterized by a well-defined vertical phase separation. To thoroughly explore device performance variations, we utilized a comprehensive array of analytical techniques, including atomic force microscopy (AFM) cross-section methodologies and Kelvin probe force microscopy (KPFM). Through the optimization of the blend ratio (PM7:IT-4F: IEICO-4F at 1:0.8:0.2), we achieved significant advancements. The resulting OPD demonstrated an exceptional reduction in JD, reaching a remarkably low value of 4.95 × 10⁻¹⁰ A cm⁻², coupled with an ultra-high detectivity of 4.95 × 10¹³ Jones and an outstanding linear dynamic range exceeding 100 dB at 780 nm under a bias of −1V. Furthermore, the attained cutoff frequency reached an impressive 220 kHz, highlighting substantial improvements in device performance metrics. Of particular significance is the successful translation of this technological breakthrough into real-world applications, such as in heart rate sensing, underscoring its tangible utility and expanding its potential across various fields. This demonstrates its practical relevance and underscores its versatility in diverse settings. Full article

Organic solar cells (OSCs) are considered a very promising technology to convert solar energy to electricity and a feasible option for the energy market because of the advantages of light weight, flexibility, and roll-to-roll manufacturing. They are mainly characterized by a bulk heterojunction structure where a polymer donor is blended with an electron acceptor. Their performance is highly affected by the design of donor–acceptor conjugated polymers and the choice of suitable acceptor. In particular, benzotriazole, a typical electron-deficient penta-heterocycle, has been combined with various donors to provide wide bandgap donor polymers, which have received a great deal of attention with the development of non-fullerene acceptors (NFAs) because of their suitable matching to provide devices with relevant power conversion efficiency (PCE). Moreover, different benzotriazole-based polymers are gaining more and more interest because they are considered promising acceptors in OSCs. Since the development of a suitable method to choose generally a donor/acceptor material is a challenging issue, this review is meant to be useful especially for organic chemical scientists to understand all the progress achieved with benzotriazole-based polymers used as donors with NFAs and as acceptors with different donors in OSCs, in particular referring to the PCE. Full article

The charge carrier formation and transport in the pristine polymers as well as in the polymer–fullerene blend is still a hot topic of discussion for the scientific community. In the present work, the carrier generation in some prominent organic molecules has been studied through ultrafast transient absorption spectroscopy. The identification of the exciton and polaron lifetimes of these polymers has led to device performance-related understanding. In the Energy Gap Law, the slope of the linear fit gradient (γ) of lifetimes vs. bandgap are subjected to the geometrical rearrangements experienced by the polymers during the non-radiative decay from the excited state to the ground state. The value of gradient (γ) for excitons and polarons is found to be −1.1 eV⁻¹ and 1.14 eV⁻¹, respectively. It suggests that the exciton decay to the ground state is likely to involve a high distortion in polymer equilibrium geometry. This observation supports the basis of Stokes shift found in the conjugated polymers due to the high disorder. It provides the possible reasons for the substantial variation in the exciton lifetime. As the bandgap becomes larger, exciton decay rate tends to reduce due to the weak attraction between the holes in the HUMO and electron in the LUMO. The precise inverse action is observed for the polymer–fullerene blend, as the decay of polaron tends to increase as the bandgap of polymer increases. Full article

The selection of the π-conjugation spacers in semi-conducting polymer backbone is one of the important factors for determining the optoelectrical and morphological properties in organic photodiodes. To study the effects of π-conjugation spacers in donor–acceptor (D-A)-type alternating copolymers on their device performances in all-polymer-based photodiodes (all-PPDs), a series of diketopyrrolopyrrole (DPP)-based copolymers as polymer donors (P_Ds) were designed and synthesized. In detail, three different π-conjugation spacers, thiophene (T for P1), thienothiophene (TT for P2), and bithiophene (BT for P3), were incorporated into the DPP-based copolymer structures. Interestingly, all-PPDs based on the series of P1–P3 as P_Ds and N2200 as a polymer acceptor (P_A) exhibited totally distinct device performances in terms of external quantum efficiency (EQE), dark current density (J_D), and ideal detectivity (D*). The P1-based device showed suppressed J_D (6.1 × 10⁻¹¹ A/cm² at −1 V) compared to those of the P2- and P3-based devices due to the lower lying of the highest occupied molecular orbital (HOMO) level of P1. However, the P3-based all-PPD showed higher EQE (16% at 630 nm wavelength and −1 V) compared to those of the P1- and P2-based devices. And, it mainly originated from the better molecular packing and final blend film morphology, as confirmed by morphological analyses. Full article

The ellipsometric analyses reported in this paper present a novelty by bringing an in-depth optical investigation of some ternary organic blends. This study focuses on the tunability and control of the relative permittivity of active layers by varying the weight ratio of blended materials spin-coated as thin films. To investigate this, an extensive approach based on spectroscopic ellipsometry was conducted on ternary blend (D:A₁:A₂) thin films, involving a donor [D = chlorinated conjugated polymer (PBDB-T-2Cl)] and two acceptor materials [A₁ = a non-fullerene (ITIC-F) and A₂ = a fullerene (PCBM)]. The refractive index constitutes a key parameter that exposes insights into the feasibility of photovoltaic cells by predicting the trajectory of light as it transits the device. In this term, higher obtained refractive indexes support higher absorption coefficients. Notably, the dielectric constant can be rigorously tuned and finely calibrated by modest variations in the quantity of the third element, resulting in considerable modifications. Moreover, the inclusion of fullerene in blends, as the third element, results in a smooth topographical profile, further refining the surface of the film. From an electrical point of view, the ternary blends outperform the polymer thin films. The synergistic interaction of constituents emphasizes their potential to enhance solar conversion devices. Full article

The morphological, spectroscopic and rheological properties of silver nanoparticles (AgNPs) synthesized in situ within commercial PEDOT:PSS formulations, labeled PP@NPs, were systematically investigated by varying different synthetic parameters (NaBH₄/AgNO₃ molar ratio, PEDOT:PSS formulation and silver and PEDOT:PSS concentration in the reaction medium), revealing that only the reagent ratio affected the properties of the resulting nanoparticles. Combining the results obtained from the field-emission scanning electron microscopy analysis and UV-Vis characterization, it could be assumed that PP@NPs’ stabilization occurs by means of PSS chains, preferably outside of the PEDOT:PSS domains with low silver content. Conversely, with high silver content, the particles also formed in PEDOT-rich domains with the consequent perturbation of the polaron absorption features of the conjugated polymer. Atomic force microscopy was used to characterize the films deposited on glass from the particle-containing PEDOT:PSS suspensions. The film with an optimized morphology, obtained from the suspension sample characterized by the lowest silver and NaBH₄ content, was used to fabricate a very initial prototype of a water-processable anode in a solar cell prepared with an active layer constituted by the benchmark blend poly(3-hexylthiophene) and [6,6]-Phenyl C61 butyric acid methyl ester (PC₆₀BM) and a low-temperature, not-evaporated cathode (Field’s metal). Full article

This study is aimed at the design, calibration, and development of a near-infrared (NIR) liquid crystal multifunctional automated optical polarimeter, which is aimed at the study and characterization of the polarimetric properties of polymer optical nanofilms. The characterization of these novel nanophotonic structures has been achieved, in terms of Mueller matrix and Stokes parameter analyses. The nanophotonic structures of this study consisted of (a) a matrix consisting of two different polymer domains, namely polybutadiene (PB) and polystyrene (PS), functionalized with gold nanoparticles; (b) cast and annealed Poly (styrene-b-methyl methacrylate) (PS-PMMA) diblock copolymers; (c) a matrix of a block copolymer (BCP) domain, PS-b-PMMA or Poly (styrene-block-methy methacrylate), functionalized with gold nanoparticles; and (d) different thicknesses of PS-b-P2VP diblock copolymer functionalized with gold nanoparticles. In all cases, backscattered infrared light was studied and related to the polarization figures-of-merit (FOM). The outcome of this study indicates that functionalized polymer nanomaterials, depending upon their structure and composition, exhibit promising optical characteristics, modulating and manipulating the polarimetric properties of light. The fabrication of technologically useful, tunable, conjugated polymer blends with an optimized refractive index, shape, size, spatial orientation, and arrangement would lead to the development of new nanoantennas and metasurfaces. Full article

The use of conjugated polymers (CPs) and metallic nanoparticles is an interesting way to form nanocomposites with improved optical properties. For instance, a nanocomposite with high sensitivity can be produced. However, the hydrophobicity of CPs may hamper applications due to their low bioavailability and low operability in aqueous media. This problem can be overcome by forming thin solid films from an aqueous dispersion containing small CP nanoparticles. So, in this work we developed the formation of thin films of poly(9,9-dioctylfluorene-co-3,4-ethylenedioxythiophene) (PDOF-co-PEDOT) from its natural and nano form (NCP) from aqueous solution. These copolymers were then blended in films with triangular and spherical silver nanoparticles (AgNP) for future applicability as a SERS sensor of pesticides. TEM characterization showed that the AgNP were adsorbed on the NCP surface, forming a nanostructure with an average diameter of 90 nm (value according to that obtained by DLS) and with a negative potential zeta. These nanostructures were transferred to a solid substrate, forming thin and homogeneous films with different morphology of PDOF-co-PEDOT films, as observed by atomic force microscopy (AFM). XPS data demonstrated the presence of the AgNP in the thin films, as well as evidence that films with NCP are more resistant to the photo-oxidation process. Raman spectra showed characteristic peaks of the copolymer in the films prepared with NCP. It should also be noted the enhancement effect of Raman bands observed on films containing AgNP, a strong indication of the SERS effect induced by the metallic nanoparticles. Furthermore, the different geometry of the AgNP influences the way in which the adsorption between the NCP and the metal surface occurs, with a perpendicular adsorption between the NCP chains and the surface of the triangular AgNP. Full article

Ultra-fine fibers derived from sea-island fibers have attracted great attention due to their excellent overall performance. However, green and efficient splitting of sea-island fibers is still a challenging task. In this work, thermoplastic polyvinyl alcohol (TPVA) was prepared by the physical blending of plasticizer. The modified TPVA showed a high decomposition temperature (285 °C) and a wide thermoplastic processing window. This made TPVA match well with polyamide 6 (PA6) to form conjugated melts at 250 °C. Corresponding PVA/PA6 sea-island fibers were first reported to realize water-splitting instead of alkali-extraction of “sea” polymers. The effects of sea/island mass ratios and different spinning speeds on the properties of PVA/PA6 sea-island pre-oriented yarn (POY) were investigated. A higher spinning speed enhanced the orientation-induced crystalline behavior of fiber, therefore increasing the tensile strength of fibers. As the increase of spinning speed from 1000 to 1500 m/min, the crystalline degree of corresponding POYs increased from 9.9 to 14.3%. The plasticizer in PVA did not diffuse to the PA matrix during spinning. However, PVA could induce the crystallization of PA6 via interfacial hydrogen bonding. When the spinning speed was 1500 m/min, and PVA/PA6 was 7:3, the tensile strength reached the highest value of 1.67 cN/dtex. The uniform diameters of ultra-fine PA6 fibers (2–5 μm) were obtained by an environment-friendly water-splitting process. The “sea” phase (TPVA) in sea-island fiber could be removed quickly by boiling water treatment in 3 min. This green and energy-saving sea-island fiber splitting technique is of great significance in reducing CO₂ emissions during the preparation of super-fine fibers. Full article

This work covers the development of non-fullerene acceptors for use in organic photovoltaics built using the N-annulated perylene diimide dye. The classic perylene diimide dye has been extensively used to construct non-fullerene acceptors, leading to device power conversion efficiencies of over 10%. Strong visible light absorption and deep frontier molecular energy levels have made such materials (both molecular and polymeric) near ideal for pairing with narrow-gap conjugated polymers in bulk-heterojunction active layers. The N-annulation of the dye provides an extra site for side-chain engineering and alters the electronic structure of the polycyclic aromatic core. In addition, N-annulation allows for selective bromination of the perylene core, leading to building blocks that are useful for the construction of large molecular frameworks using the atom-economical direct heteroarylation cross-coupling method. Herein, we detail a series of molecules developed by our team that are based on the N-annulated perylene diimide in the form of dimers with different cores (both electron-rich and electron-deficient); dimers with varied side chains; tetramers with varying geometries; and large, asymmetric molecules with internal energy cascades. The use of these molecules as non-fullerene acceptors in organic photovoltaic devices (binary and ternary blends, outdoor and indoor light applications, and spin-coated vs. slot-die-coated photoactive layers) is presented. Full article

Metal additive processing in polymer: fullerene bulk heterojunction systems is recognized as a viable way for improving polymer photovoltage performance. In this study, the effect of niobium (Nb) metal nanoparticles at concentrations of 2, 4, 6, and 8 mg/mL on poly(3-hexylthiophene-2,5-diyl) (P3HT)-6,6]-phenyl C61-butyric acid methyl ester (PCBM) blends was analyzed. The effect of Nb volume concentration on polymer crystallinity, optical properties, and surface structure of P3HT and PCBM, as well as the enhancement of the performance of P3HT:PC61BM solar cells, are investigated. Absorption of the P3HT:PC61BM mix is seen to have a high intensity and a red shift at 500 nm. The reduction in PL intensity with increasing Nb doping concentrations indicates an increase in PL quenching, suggesting that the domain size of P3HT or conjugation length increases. With a high Nb concentration, crystallinity, material composition, surface roughness, and phase separation are enhanced. Nb enhances PCBM’s solubility in P3HT and decreases the size of amorphous P3HT domains. Based on the J–V characteristics and the optoelectronic study of the thin films, the improvement results from a decreased recombination current, changes in morphology and crystallinity, and an increase in the effective exciton lifespan. At high doping concentrations of Nb nanoparticles, the development of the short-circuit current (J_SC) is associated with alterations in the crystalline structure of P3HT. The highest-performing glass/ITO/PEDOT:PSS/P3HT:PCBM:Nb/MoO₃/Au structures have short-circuit current densities (J_SC) of 16.86 mA/cm², open-circuit voltages (V_OC) of 466 mV, fill factors (FF) of 65.73%, and power conversion efficiency (µ) of 5.16%. Full article