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The newly synthesized fused tetrathienophenanthroline (TTP) acceptor molecule, achieved via one-pot superacid catalyzed intramolecular cyclization, offers a promising alternative to the conventional benzodithiophene-4,8-dione (BDD) moieties in high-performance photovoltaic materials. The S, N heteroacene type TTP core exhibits complete planarity and enhanced electron richness compared to the BDD core, paving the way for fine tuning the morphology, optoelectronic properties, and frontier molecular energy levels in donor–acceptor-type materials. Side-chain engineering resulted in a balanced electron-rich nature of the monomer and enhanced solubility/processability of the resulting polymers. These molecular strategies for PTTP1-BDT contribute to improved stability and morphology, crucial for organic electronic device applications. Incorporation of PTTP1-BDT and PBDB-T as donor polymers in organic photovoltaics resulted in a power conversion efficiency (PCE) of ∼3% for PTTP1-BDT and ∼8% for PBDB-T. The compromise in PTTP1-BDT based device efficiency was attributed to lower and unbalanced charge mobility.

Regioregularity in conjugated polymers plays a significant role in enhancing the semiconducting properties and narrowing the optical band gap. Two donor–acceptor copolymers, specifically quinoxaline-thienylenevinylene (P1) and regioregular pyridyl pyrazine-thienylenevinylene (P2), were synthesized and characterized. Their potential applications in organic field-effect transistors (FETs) and complementary inverter circuits were explored. P2 exhibits a narrower absorption spectrum with distinct vibronic peaks compared to P1. In both top-gate and bottom-gate FET architectures, the copolymers display p-type behavior, with P2 demonstrating approximately an order of magnitude higher carrier mobility (∼10–3 cm2/(V s)) than P1. The performance of the FETs is further improved by the surface treatment of the source–drain contacts, which is particularly noticeable in P1. These p-type FETs, incorporating P1 and P2, were employed in complementary voltage inverter circuits along with thiazole-selenophene-linked fluorinated isoindigo (IID-TzSe) n-type organic FETs. The P1–IID-TzSe inverter, characterized by balanced p- and n-channels with similar threshold voltages, shows a gain >20 at a supply voltage of 50 V. Similar gains are also observed in the P2–IID-TzSe inverter circuits.

In addition to providing a sustainable route to green alternative energy and chemical supplies from a cheap and abundant carbon source, recycling CO2 offers an excellent way to reduce net anthropogenic global CO2 emissions. This can be achieved via catalysis on 2D materials. These materials are atomically thin and have unique electrical and catalytic properties compared to bigger nanoparticles and conventional bulk catalysts, opening a new arena in catalysis. This paper examines the efficacy of hexagonal boron nitride (h-BN) lattices with vacancy defects for CO2 electroreduction (CO2RR). We conducted in-depth investigations on different CO2RR electrocatalytic reaction pathways on various h-BN vacancy sites using a computational hydrogen model (CHE). It was shown that CO binds to h-BN vacancies sufficiently to ensure additional electron transfer processes, leading to higher-order reduction products. For mono-atomic defects VN (removed nitrogen), the electrochemical path of (H+ + e−) pair transfers that would lead to the formation of methanol is most favorable with a limiting potential of 1.21 V. In contrast, the reaction pathways via VB (removed boron) imposes much higher thermodynamic barriers for the formation of all relevant species. With a divacancy VBN, the hydrogen evolution reaction (HER) would be the most probable process due to the low rate-determining barrier of 0.69 eV. On the tetravacancy defects VB3N the pathways toward the formation of both CH4 and CH3OH impose a limiting potential of 0.85 V. At the same time, the HER is suppressed by requiring much higher energy (2.15 eV). Modeling the edges of h-BN reveals that N-terminated zigzag conformation would impose the same limiting potential for the formation of methanol and methane (1.73 V), simultaneously suppressing the HER (3.47 V). At variance, the armchair conformation favors the HER, with a rate-determining barrier of 1.70 eV. Hence, according to our calculations, VB3N and VN are the most appropriate v

Nitrogen-doped carbon dots (NCD) were synthesized using a simple and fast hydrothermal route, employing citric acid and urea as precursors. The resulting NCDs were non-covalently functionalized (conjugated) with aromatic amino acids, namely phenylalanine (Phe) and tryptophan (Trp). Atomic force microscopy revealed that the NCDs exhibit a disk-like morphology with an average diameter of approximately 60 nm and an average height of about 0.5 nm. Following conjugation, the particle height increased to around 3 nm. UV–vis spectroscopy analysis indicated successful conjugation of the amino acids to the NCD nanostructures. Additionally, DFT numerical calculations based on three differently N-doped clusters were performed to elucidate the nature of the non-covalent interactions between NCDs and the corresponding amino acids. Photoluminescent spectra demonstrated a stable and strong fluorescence signal for both hybrids in the UV region. The most significant changes were observed in the case of Trp-conjugation. In contrast to phenylalanine, the non-covalent bonding of tryptophan to NCDs strongly influenced the visible emission (around 500 nm) originating from surface states of the dots.

Nitrogen-doped carbon quantum dots (N-CQDs) are promising next generation nanomaterials for potential biomedical applications such as bioimaging, biosensing, and drug/gene delivery. However, N-CQDs biocompatibility has not been extensively investigated. Here, we report physico-chemical characteristics of newly synthetized N-CQDs and their effects on red blood cells (RBC), by analyzing their hemolytic activity, impact on RBC rheology/morphology, and oxidative stress induction. N-CQDs were prepared by hydrothermal method using citric acid and urea as precursors. Structural analyses of as prepared N-GQDs, observed by HRTEM/EDS, showed that the lateral dimensions of the particles are in the 10 to 20 nm range, as well as that the carbon, oxygen, and nitrogen are present in the nanosystem. Based on AFM measurements, the average height of N-CQDs was 3.9±0.08 Å. Photoluminescence emission (PLE) spectrum demonstrated that N-CQDs exhibit stable and strong fluorescence in green (520 nm) region, upon 410 nm excitation. FTIR spectroscopy indicated vibrational bands, characteristic for carbon structures and primary amines (Ndoping). N-CQDs were negatively charged with an average Zeta potential of -15.3 mV as confirmed by DLS. To investigate hemocompatibility of N-CQDs, the RBC, the most abundant cells in blood, were treated with different concentration of N-CQDs (10-400 ug/ml) for 2h. Obtained results showed that there was no hemolytic activity. Moreover, ektacytometry analysis demonstrated that N-CQDs did not affect deformability of RBC. Fluorescent microscopy analyses revealed that treatment with N-CQDs did not induce significant morphological aberrant forms of RBC which was also confirmed by SEM analyses. Flow cytometry confirmed only slight RBC morphological changes based on FSC/SSC analysis. Furthermore, using ROS sensitive dye flow cytometry analyses suggested that N-CQDs did not induce oxidative stress in RBC. Taken together, our findings highlighted that exposure of RBC t

Graphene quantum dots, zero-dimensional form of graphene, have a band gap that can be controlled by changing their size, shape, edge morphology, number of layers etc. Moreover, they have various edge terminations that can be physically/chemically functionalized for numerous applications in nano electronics, biosensors, supercapacitors, and nanomedicine. In the present study, we hydrothermally synthesized nitrogen-doped graphene quantum dots (NGQD), using simple, fast synthetic route and eco-friendly chemicals, such as citric acid and urea (amine group-rich). The obtained NGQD were physically functionalized by L-phenylalanine, aromatic amino acid with interesting fluorescent properties. The hybrid NGQD-LPhe samples were characterized with UV/Vis, Raman, ATR Fourier transformed infra-red and photoluminescence (PL) spectroscopies, while their morphologies were studied by using atomic force microscopy. This work created a base for future investigations on graphene/biomolecules hybrids and their applications in fields of bioimaging and drug delivery. In addition, the experimental results were supported by DFT calculations of non-covalent stacking and hydrogen bonding interactions between NGQD and biomolecules.

Visible-light-responsive graphite-embedded titanium dioxide nanofibers (G-TiO2 NFs), prepared by electrospinning and post-treatment with rhodizonic acid (RhA), show biocidal effects against E. coli and S. aureus when excited with visible light. The red absorption shift of surface-modified G-TiO2 NFs with RhA of about 1.1 eV is a consequence of interfacial charge transfer (ICT) complex formation facilitated by a condensation reaction between hydroxyl groups originating from the ligand and surface TiO2. The optical properties of the inorganic–organic hybrid are studied in-depth by density functional theory (DFT) calculations using a cluster model. The prepared samples are thoroughly characterized using X-ray diffraction (XRD) analysis, electron paramagnetic resonance spectroscopy (EPR), Fourier-transform infra-red (FTIR) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Under visible light illumination, surface-modified G-TiO2 NFs display a near-to ideal biocidal effect against E. coli and S. aureus and no cytotoxicity was observed toward L929 fibroblast cells. Overall, the experimental results suggest that fabrics based on surface-modified G-TiO2 NFs with RhA can be potentially used to control the persistence and spread of bacterial infection.

The interfacial charge transfer (ICT) complex formation between zirconium dioxide (ZrO2), the material absorbing below 250 nm, and 5-aminosalicylic acid (5-ASA) leads to the formation of visible-light-absorbing inorganic–organic hybrids. The free amino groups, present on the hybrid's surface after the ICT complex formation, were used to reduce silver ions and link silver particles to ZrO2. The prepared samples were characterized by using transmission electron microscopy, X-ray diffraction analysis, and nitrogen adsorption–desorption isotherms. Density functional theory (DFT) calculations using a cluster model are applied to explain optical changes in hybrids, i.e., absorption redshift induced by the ICT complex formation. Decolorization of an organic dye crystal violet (CV), under ultraviolet-C or visible light, was used to compare the photocatalytic ability of the prepared samples. The ICT complex formation transformed ZrO2 into a hybrid material able to induce photocatalytic reactions under exclusive visible light excitation.

Cink oksid (ZnO) je poluprovodni material sa velikim energetskim procepom, sa najčešćom primenom u fotokatalizi. Površinska modifikacija nanočestica ZnO ligandima salicilatnog tipa (salicilna kiselina i 5-aminosalicilna kiselina) kao i ligandima kateholatnog tipa (katehol, 3,4-dihidroksibenzoeva kiselina i kafeinska kiselina) dovodi do pomeranja apsorpcije ka vidljivom delu spectra usled formiranja kompleksa sa prenosom naelektrisanja (ICT). Pripremljeni uzorci su okarakterisani infracrvenom spektroskopijom (FTIR) koja je korišćena za identifikaciju načina vezivanja između liganada i ZnO. Proračuni teorije funkcionalne gustine (DFT) sa pravilno dizajniranim klasterima, izvedeni su za procenu usklađenosti energetskih nivoa različitih neorganskih/organskih hibrida. Utvrđena je značajna usaglašenost između izračunatih i eksperimentalnih vrednosti za FTIR i refleksione spektre., Zinc oxide (ZnO) is a wide bandgap ceramic material with various potential applications like photocatalysis. Surface modification of ZnO nano-powder with salicylate-type ligands (salicylic acid and 5-aminosalicylic acid) as well as catecholate-type ligands (catechol, 3,4dihydroxybenzoic acid, and caffeic acid), induces the appearance of absorption in the visible spectral region due to the interfacial charge transfer (ICT) complex formation. The prepared samples were characterized by Fourier-transform infrared spectroscopy (FTIR), used to identify the binding mode between ligands and the surface of ZnO. The density functional theory (DFT) calculations with properly designed model systems, were performed to estimate the alignment of energy levels of various inorganic/organic hybrids. A reasonably good agreement between calculated values and experimental data for FTIR and reflectance spectra was found.

Despite ample studies devoted to single-atom catalysts (SACs) based on two-dimensional materials, their structural robustness under atmospheric conditions has not been addressed so far. Using density functional theory, we examined the structural stability of metal adatoms embedded into mono-atomic vacancies of graphene and hexagonal boron nitride (h-BN) in the presence of oxygen molecules. We considered 30 different elements from the periodic table, including early- and late transition as well as noble metals. We found that the highest stability occurs in SACs with a missing B atom in h-BN, utilized as the trapping site for metal adatoms. The structural stability is preserved for most of the transition metals embedded into mono-atomic vacancies of graphene. The least stable are SACs formed when metal binding occurs at the missing N atom in h-BN. We found that a general picture of the structural stability of SACs in the oxygen environment can be provided from the comparison of binding energies of O and metal atoms at three defected surfaces. A refined understanding of the structural stability of SACs requires coadsorption of metal and O atoms and a closer inspection of electronic properties of metal atoms and mono-atomic point defects at graphene and h-BN, which is also presented here.

Aqueous colloids, consisting of 15–30 nm-sized silver nanoparticles (Ag NPs), were prepared using the reducing and stabilizing abilities of glucose, sucrose, and dextran. The long-term stability of coated Ag NPs increases from glucose over sucrose to dextran, i.e., with the increase of the molecular weight of carbohydrate molecules. The density functional theory (DFT) calculations of the partial atomic (Mulliken) charges and adsorption energies are applied to explain the enhanced stability of coated Ag NPs. All coated Ag NPs have a significantly broader concentration range of nontoxic behavior toward pre-osteoblast cells than bare Ag NPs prepared using sodium borohydride. The carbohydrate-coated Ag NPs display the same level of toxic ability against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria as bare Ag NPs. The differences in toxicity mechanism of the coated and bare Ag NPs are a consequence of the absence and presence of co-occurring Ag+ ions in examined dispersion, respectively.

The optical properties of surface-modified silver nanoparticles (Ag NPs) with aromatic amino acids tryptophan (Trp) and histidine (His) were examined using the cluster model for density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. Also, the redistribution of electronic charges upon chemisorption of ligand molecules onto silver's surfaces is determined. The obtained theoretical data, on one side, undoubtedly indicate the the formation of an interfacial charge transfer (ICT) complex between silver and this type of ligand, and, on the other side, partial oxidation of surface silver atoms accompanied by an increase of electron density in ligand molecules. The ICT complex formation, based on noble metal nanoparticles, has never been reported previously to the best of our knowledge. The experimental spectroscopic measurements support the theoretical data. A new absorption band in the visible spectral range appears upon surface modification of Ag NPs, and, when exposed to air, oxidation of surface-modified Ag NPs is significantly faster than the oxidation of the unmodified ones.

The increasing presence of pesticides and heavy metals in the environment and their negative impact on human, animal, and plant health, demand green, low-cost, and simple methods for their monitoring. Due to photoluminescence (PL) in the visible part of the spectrum, biocompatibility, and ecological acceptability, graphene quantum dots (GQDs) are at the center of attention in the field of optical sensing. GQDs show great potential as PL sensors for Pd(II) ions and insecticide carbofuran. In this work, FTIR spectroscopy and Density Functional Theory (DFT) calculation were used to resolve the mechanism of PL change in the presence of these analytes.

The antibacterial performance and cytotoxic examination of in situ prepared silver nanoparticles (Ag NPs), on inorganic-organic hybrid nanopowder consisting of zirconium dioxide nanoparticles (ZrO2 NPs) and dihydroquercetin (DHQ), was performed against Gram (−) bacteria Escherichia coli and Gram (+) bacteria Staphylococcus aureus, as well as against human cervical cancer cells HeLa and healthy MRC-5 human cells. The surface modification of ZrO2 NPs, synthesized by the sol-gel method, with DHQ leads to the interfacial charge transfer (ICT) complex formation indicated by the appearance of absorption in the visible spectral range. The prepared samples were thoroughly characterized (TEM, XRD, reflection spectroscopy), and, in addition, the spectroscopic observations are supported by the density functional theory (DFT) calculations using a cluster model. The concentration- and time-dependent antibacterial tests indicated a complete reduction of bacterial species, E. coli and S. aureus, for all investigated concentrations of silver (0.10, 0.25, and 0.50 mg/mL) after 24 h of contact. On the other side, the functionalized ZrO2 NPs with DHQ, before and after deposition of Ag NPs, do not display a significant decrease in the viability of HeLa MRC-5 cells in any of the used concentrations compared to the control.