Photoactive Materials Research Articles

One-pot preparation of Bi/BiOF/Bi2O2CO3 Z-scheme heterojunction with enhanced photocatalysis activity for ciprofloxacin degradation under simulated sunlight

To improve the photocatalytic activity of BiOF under simulated sunlight irradiation, a ternary Bi-based Z-scheme heterojunction of Bi/BiOF/Bi2O2CO3 nanosheets were prepared using one-pot hydrothermal technique, where N, N-dimethylformamide was used as carbon source for Bi2O2CO3 and reductant for metal Bi, bismuth nitrate was employed as Bi source and NaF was used as F source. The photocatalytic activity of Bi/BiOF/Bi2O2CO3 was improved greatly towards ciprofloxacin degradation with the reaction kinetic constant of 0.0649 min−1, which was 7 and 3.5 times to that of BiOF and Bi2O2CO3, respectively. The improved photocatalytic activity was ascribed to the surface plasmon resonance effect of metal Bi and the synergistic effects of BiOF/Bi2O2CO3 Z-scheme heterojunction, which facilitated the migration of the photogenerated electron and inhibited the recombination of photogenerated e−/h+ pairs. The degradation mechanism and charge transfer pathway were confirmed. This work expands the application of BiOF-based photoactive materials in environmental field.

Antimicrobial efficacy of solar disinfection in cellulose fiber supported photoactive materials

According to the World Health Organization, antimicrobial resistance is one of the emerging threats to global health. Therefore, the development of new strategies to mitigate resistant bacterial strains is highly desirable. Photodynamic inactivation is a promising approach owing to its effectiveness against a broad range of microorganisms irrespective of their antibiotic resistance profile and its multitarget mechanism that hamper the appearance of acquired resistance. In this work, a self-sterilizing and potentially biodegradable material is developed, providing a green alternative for single-use packaging in the medical, food, and cosmetic industry. We demonstrate two synthetic approaches based on covalent linkage of toluidine blue to tempo-oxidized carbon nanofibers, as well as the supramolecular immobilization based on electrostatic self-assembly. The former shows high activity, reaching inactivation rates of 8 Log10 CFU for S. aureus and E. coli after 15 min under 250 W·m−2 artificial sun irradiation. This simple and facile approach will enable the preparation of composite photoantimicrobial films that are light activated, providing clean and microbiologically safe surfaces, even in challenging situations, such as natural disasters or conflicts, or remote locations with of none or limited access to other forms of energy supply.

Metal-Organic Framework Based on Pyrazinoquinoxaline Tetracarboxylic Acid for Fluorescence Sensing for Nitro Explosives.

The rapid and selective detection of nitro explosives has become one of the current urgent environmental and safety issues. Fluorescent metal-organic frameworks (MOFs) provide strong support for the development of photoactive materials with excellent sensing performances. In this work, Zn2+ and pyrazinoquinoxaline tetracarboxylic acid with high nitrogen content were selected to construct a MOF structure termed Zn-MOF, which had excellent optical properties. The fluorescence sensing performance of Zn-MOF for nitro explosives was also investigated. The structural advantages of Zn-MOF, such as its porous structure, abundant host-guest interaction sites, and stable framework, ensure the prerequisites for various applications. Zn-MOF is not only capable of responding to a wide range of substrates, such as Fe3+, Cr2O72-, and MnO4-, to achieve fluorescence quenching detection but also able to achieve sensitive fluorescence sensing behavior for nitro explosives. In particular, for trinitrotoluene, the Ksv value can reach 8.72 × 103 M-1. The results show that the introduction of pyrazinoquinoxaline groups into MOFs can be an effective strategy for the preparation of highly efficient fluorescent sensing materials for nitro explosives.

Recent progress in device designs and dual‐functional photoactive materials for direct solar to electrochemical energy storage

AbstractEfficient solar energy utilization technologies are expected to promote the development of a carbon‐neutral and renewable energy society. Photovoltaic cells (PVs) have played an important role in the harvest and conversion of solar energy. Due to the intermittent instability of solar energy, however, PVs must be connected with energy storage systems (EESs). Newly developed photoelectrochemical energy storage devices (PESs) are proposed to directly convert solar energy into electrochemical energy. Initial PESs focused on the external and internal integration of PVs and EESs. However, the voltage mismatch between PVs and EESs leads to massive energy loss and unsatisfactory overall performances of PESs. PESs using dual‐functional photoactive materials (PAMs), which have simplified device configuration, decreased costs, and external energy loss, have recently emerged for realization of solar‐to‐electrochemical‐energy conversion and storage in a single device. The review summarizes the designing concepts, integrated configurations, and overall performances of different types of PESs, particularly PESs utilizing dual‐functional PAMs. Based on the classifications, working principles, basic requirements, and design principles, this review discusses various types of PESs cathodes. Finally, some perspectives are provided for further developing excellent performances of PESs.

β-Bi2O3-Bi2WO6 Nanocomposite Ornated with meso-Tetraphenylporphyrin: Interfacial Electrochemistry and Photoresponsive Detection of Nanomolar Hexavalent Cr.

Hexavalent chromium exposure via inhalation, ingestion, or both has been proven to adversely affect internal organs, induce toxic effects, cause allergies, and contribute to the development of cancer. It requires a substantial and challenging effort to detect several heavy metal ions conveniently, sensitively, and reliably by using materials that are easy to synthesize and have a high yield. The impact of light on the electrocatalytic oxidation/reduction process proves an environmentally friendly methodology with numerous applications in pollution control. The extensive use of photoactive materials in photoelectrochemical (PEC) sensors necessitates the development of stable and highly effective photoactive materials. Hence, the solvothermal synthesis of the organic-inorganic hybrid nanocomposite β-Bi2O3-Bi2WO6/H2TPP with varying weight percentages of meso-tetraphenylporphyrin (H2TPP) resulted in a selective electrode for electrocatalytic and photoelectrocatalytic reduction of Cr6+ on fluorine-doped tin oxide (FTO) by an adsorption-reduction mechanism. H2TPP increases the active site density and provides an effective surface area for efficient adsorption by providing both pyridinic- and pyrrolic-N atoms to β-Bi2O3-Bi2WO6/H2TPP. H2TPP could effectively adsorb Cr6+ in the β-Bi2O3-Bi2WO6/H2TPP composite system through electrostatic interaction, and the adsorbed Cr6+ ions were reduced to trivalent chromium Cr3+, resulting in promising Cr6+ sensing. The projected density of states and Bader charge calculations result in the electrostatic attraction among the N-2p orbital of H2TPP and the 3d and 4s orbitals of the Cr atom, resulting in the adsorption of the hexavalent Cr atom onto the active center of H2TPP. Moreover, the addition of H2TPP results in the development of a mesoporous surface that offers strong electrical conductivity, a substantial surface area, improved charge-mass transport, intimate contact between the electrolyte and catalyst, an extended fluorescence lifetime, and increased stability. The role of pH values was thoroughly investigated. All electrochemical and photoelectrochemical studies were carried out on 5 wt % H2TPP-ornated β-Bi2O3-Bi2WO6. Nanocomposite β-Bi2O3-Bi2WO6/5 wt % H2TPP demonstrated reliable cyclic stability, reproducibility, good sensitivity (8.005 μA mM cm-2), and a low limit of detection (LOD) (8.0 nM) toward photoelectrocatalytic reduction of Cr6+. The interference study in the presence of a few inorganic entities exhibited excellent selectivity. This tale amplification approach for developing a β-Bi2O3-Bi2WO6/5 wt % H2TPP nanocomposite system suggests a deeper understanding of the application of photoelectrocatalytic reduction of Cr6+ in environmental remediation with real samples under light irradiation.

INFLUENCE OF DOPING WITH CARBON AND NITROGEN ON THE PHOTOACTIVITY OF TiO2 THIN FILMS OBTAINED WITH MePIIID

Titanium dioxide is well known as a photoactive material activated under ultraviolet irradiation. It is either employed as a photocatalyst or it exhibits superhydrophilic behavior after obtaining reduced surface energy under illumination used for self-cleaning or anti-fogging surfaces. For increasing the reactivity of thin films under solar illumination, a reduced band gap is desired. Doping with transition metals or nitrogen has been reported in the literature. However, the incorporation of nitrogen into a growing film is a much more complex process that is presently not completely understood. TiO2 thin layers were produced by metal plasma immersion ion implantation and deposition at room temperature at a pulse voltage of 0–5 kV and a duty cycle of 9 % for an apparently amorphous layer. An auxiliary rf plasma source was employed to increase the growth rate at low gas flow ratios. By adjusting the geometry between the incident ion beam, sputter target and substrate independently of the primary ion energy and species, a controlled deposition of samples was possible. Conventional ion implantation was employed to implant either carbon or nitrogen ions below the surface for bandgap engineering. The resulting thin films were subsequently investigated for optical properties, stoichiometry, structural properties, surface topography and photoactivity.

Naturally J-aggregated F-BODIPYs: Self-assembly organization driven by substitution pattern

The development of self-assembled dyes able to display J-aggregation-induced emission has gained a renewed interest as an appealing and distinctive approach for the design of smart photoactive materials. F-BODIPY dyes have been exploited to this aim since J-type supramolecular organization has been effectively photoinduced under specific surrounding conditions (hydrophilic or constrained media) although, up to date, it has never been observed in pure organic media. Herein, we report the first systematic study of the self-assembly properties of F-BODIPYs in pure organic solvents and analyze in depth the control exerted by the substitution pattern of its carbon skeleton into the formation of emissive J-aggregates. Spontaneous J-aggregation in F-BODIPYs is evidenced by their lasing properties and supported by the analysis of their solid-state photophysics and X-ray crystalline packing as well as by molecular dynamics in solvent cages. These studies point out the key role of the stereoelectronic properties of the substituents orthogonally grafted at the dipyrrin core (meso and C-2 and C-6 positions) as the main driving force to control the molecular stacking arrangement of F-BODIPYs in common organic solvents. The understanding of the interplay between the molecular structure and the properties of the resulting aggregates sheds light on the workability of BODIPY-based self-assembly as a tool for advanced luminescent materials.

Active polymer-based halide perovskites for light-driven applications: A review

Halide perovskites (HPs) are gaining traction as effective photoactive materials due to their unique properties in numerous applications, which have significantly demonstrated several methods in improving HPs. Nonetheless, the role of active polymers in HPs as significant photoactive materials is still poorly investigated. Thus, this review comprehensively studied the current state-of-the-art active polymer-based HP photoactive materials. The potential benefits of polymer-based HPs were highlighted in multiple applications, including environmental remediation, water splitting, and energy conversion. This outcome addressed the research gap concerning the role of active polymers that substantially improved the performance of these applications. Since polymers remained a key addition to improving HPs, further investigation and research could lead to significant advancements in these areas.

Ultrasensitive and selective detection of ciprofloxacin in milk based on organic photoelectrochemical transistor aptasensor enhanced by high capacitance Ti3C2/TiO2

Ciprofloxacin (CIP) in milk has a harmful effect on human health, it’s important to conduct ultra-sensitive selective detection of ciprofloxacin. Herein, an ultrasensitive and selective organic photoelectrochemical transistor (OPECT) CIP aptasensor was constructed using Ti3C2/TiO2 composites as gate photoactive materials. Compared with Ti3C2, TiO2, and Ti3C2/TiO2 mixed by physical, Ti3C2/TiO2 composites exhibits larger capacitance and the OPECT intensity is 3 times of Ti3C2, 2 times of Ti3C2/TiO2 mixed by physical and TiO2, which attributed to higher capacitance of Ti3C2/TiO2 composites provides high electrostatic charge storage capacity and leads to effective gating, induces more electronic charge in the channel and larger drain currents. Exemplified by CIP as target, the developed sensor achieves sensitive detection with linear range from 3 ng/L to 3 mg/L, detection limit is 1 ng/L. This work completed the detection in real samples, which lays a foundation for the construction of OPECT food safety analysis and detection platform.

Photo-active hybrid materials based on polyoxometalate anion and ethidium cation

We report the synthesis and photoluminescence (PL) properties of three compounds [C21H20N3]2[HPMo12O40] (1), [C21H20N3]3[PW12O40]∙4C3H7NO (2) and [C21H20N3]4[SiW12O40] (3) consisting of ethidium cation (3,8-diamino-5-ethyl-6-phenylphenanthridinium) and Keggin type polyoxometalates. Compounds 1, 2 and 3 have been characterized unambiguously by the single crystal X-ray diffraction studies. The binding studies of inorganic-organic hybrid compounds 1, 2 and 3 with CT-DNA (calf thymus DNA) have been carried out and monitored by UV–Vis- and emission-spectroscopy. The compounds 1 and 2 show fluorescence enhancement where as compound 3 with silicotungstate polyanion shows fluorescence quenching. The photoluminescence properties of three hybrid compounds arise due to the interaction of ethidium cation with DNA. We have demonstrated that the interaction between ethidium cation and CT-DNA is influenced by a particular type of polyoxometalate (POM) Keggin anion. The crystal structures show supramolecular interactions between the Keggin anion and ethidium cation. Compounds 1, 2 and 3 are further characterized by routine spectral analysis.

Polypyrrole participates in the construction of a polarity-switchable photoelectrochemical molecularly imprinted sensor for the detection of acrylamide in fried foods

Designing a polarity-switchable photoelectrochemical (PEC) sensor is important, but there are significant challenges due to the difficulty in adjusting the polarization of photoelectric or photoactive materials. In this manuscript, we established a simple and polarity-switchable molecularly imprinted polymer (MIP)-PEC sensor based on a “Z-scheme” strategy for detecting acrylamide (AM). First, we prepared a composite material of MoS2/rGO/Au (MGA) with a large specific surface area and good electrical conductivity that was sensitive to visible light. Second, the photoactive material MGA was used as the substrate material and polypyrrole (PPy) was acted as the functional monomer associated with the template molecule AM to construct the MIP working electrodes. PPy not only dressed up as a functional monomer but also as a polarity switcher, creating an in-situ-grown PPy/MGA heterojunction with a charge-carrier transport path similar to the letter “Z.” The design of the Z-scheme strategy not only increased the signal intensity of the photocurrent but also switched the photocurrent polarity from the anode to the cathode, avoiding the interference of a false positive or a false negative. When using this PEC-MIP sensor for the quantitative detection of AM, the detection limit was 1.7 pmol for the linear range of 0.25–10000 nmol. The proposed sensor exhibited satisfactory sensitivity and selectivity, and it has great potential for monitoring emerging food safety risks.

Processability Considerations for Next-Generation Organic Photovoltaic Materials.

The evolution of organic semiconductors for organic photovoltaics (OPVs) has resulted in unforeseen outcomes. This has provided substitute choices of photoactive layer materials, which effectively convert sunlight into electricity. Recently developed OPV materials have narrowed down the gaps in efficiency, stability, and cost in devices. Records now show power conversion efficiency in single-junction devices closing to 20%. Despite this, there is still a gap between the currently developed OPV materials and those that meet the requirements of practical applications, especially the solution processability issue widely concerned in the field of OPVs. Based on the general rule that structure determines properties, methodologies to enhance the processability of OPV materials are reviewed and explored from the perspective of material design and viewson the further development of processable OPV materials are presented. Considering the current dilemma that the existing evaluation indicators cannot reflect the industrial processability of OPV materials, a more complete set of key performance indicators are proposedfor their processability considerations. The purpose of this perspective is to raise awareness of the boundary conditions that exist in industrial OPV manufacturing and to provide guidance for academic research that aspires to contribute to technological advancements.

A donor-acceptor-type photoactive material based cathode molecularly imprinted photoelectrochemical sensor for luteolin

Developing new optoelectronic materials is the eternal pursuit and key strategy for building high-performance photoelectrochemical sensors. In this work, a novel organic polymer film containing D-A unit was firstly in-situ electro-synthesized on ZnS/rGO surface by using 9,9′-(9,9′-spirobi[fluorene]−2,7-diyl)-bis-9 H-carbazole (SFC) and carbazole as functional monomers. The micromorphology, element composition, structure, photoelectric efficiency and recognition ability of the key component and/or the sensing composite were investigated by SEM, XPS, XRD and transient photocurrent spectra, and the possible mechanism of charge carrier separation and transmission was proposed. Owing to the good light absorption ability, excellent film formation and imprinting ability, effective electrons-holes separation path, and satisfactory application stability, the prepared photoelectrochemical sensor exhibited good sensing performance for luteolin. Under the optimized conditions, the photocurrent intensity of the sensor showed a good linear relationship with the logarithmic concentration of luteolin from 0.001 μmol L−1 to 2 μmol L−1, with a detection limit of 0.35 nmol L−1 (S/N = 3). When applied in actual samples including carrot, peanut shells and chrysanthemum tea, highly consistent results with classical HPLC method were obtained. This work provided a new photoelectrochemical approach for the highly selective and sensitive detection of small molecules besides luteolin.

Efficient and Stable Tin–Lead Perovskite Photoconversion Devices Using Dual‐Functional Cathode Interlayer

AbstractTin–lead halide perovskites (TLHPs) are promising photoactive materials for photovoltaics (PVs) due to reduced toxicity and broad light absorption. However, their inherent ionic vacancies facilitate inward metal diffusion, accelerating device degradation. Here, efficient, stable TLHP‐based PV and photoelectrochemical (PEC) devices are reported containing a chemically protective cathode interlayer—amine‐functionalized perylene diimide (PDINN). Solution‐processed PDINN effectively extract electrons and suppress inward‐metal diffusion by forming tridentate metal complexes with its nucleophilic sites. The PV device achieved an efficiency of 23.21% (>81% retention after 750 h at 60 °C and >90% retention after 3100 h at 23 ± 4 °C), and the first demonstration of TLHP‐based PEC devices exhibit a record‐high bias‐free solar hydrogen production rate (33.0 mA cm−2; ≈3.42 × 10−6 kg s−1 m−2) when coupled with biomass oxidation, which is ≈1.7‐fold higher than the ultimate target set by the U.S. Department of Energy for one‐sun hydrogen production. These findings demonstrate the potential of TLHPs for efficient, stable photoconversion by the molecular design of the cathode interlayer.

Samarium-modified NBT ceramics: a comprehensive exploration of cumulative effects

In the present report, ceramic specimens of sodium bismuth titanate [Na0.5(Bi1-xSmx)0.5TiO3] were prepared through solid-state reaction method with variations in the dopant concentrations specifically, x = 0.0, 0.1, 0.3, 0.5. The structural, optical, mechanical, and magnetic properties of lead-free NBT ceramics were investigated. The rhombohedral phase with space group R3c was confirmed in all prepared ceramic samples using X-ray diffraction patterns and Rietveld analysis. SEM micrographs and Energy Dispersive x-ray spectroscopy (EDAX) assess the morphology, grain size, overall structure, and stoichiometry of the developed compounds. FTIR spectroscopy was used for characterizing and identifying the functional groups. UV–vis spectroscopy revealed that band gap values decreased as dopant concentration increased, confirming the use of NBT-based perovskite as a photoactive material. PL spectra at room temperature exhibited reddish-orange emission. Colour coordinates and CCT values are in the range of 3483 K to 5912 K. At a concentration of x = 0.3, the materials displayed a high Vickers hardness of 8.20 GPa and exhibited minimal wear with low frictional coefficient values. Ferromagnetic behaviour at room temperature (RTFM) was detected in Sm-modified ceramic samples, as confirmed by the VSM study. The cumulative effect impact of the rare earth dopant cation at the Bi-site of NBT was widespread and demonstrated significant potential for use in optoelectronic devices.

Initial dynamic photoactive materials testing of an atmospheric chamber intended for radioactive and hazardous gases

Initial dynamic photoactive materials testing of an atmospheric chamber intended for radioactive and hazardous gases

A sensitive signal off photoelectrochemical aptasensor based on CuO nanosheets @Au nanoflowers for the detection of chloramphenicol

A signal off type photoelectrochemical (PEC) aptasensor was constructed for the sensitive detection of chloramphenicol based on CuO nanosheets (CuO NSs) and gold nanoflowers (Au NFs) modified indium tin oxide (ITO) electrode. CuO NSs was p-type photoactive semiconductor materials, which had narrow band gap and high absorption rate of visible light. After combining with Au NFs, the composite CuO NSs@Au NFs produced a strong cathodic photocurrent for the excellent electron conductivity, large specific surface area and Surface Plasmon Resonance effect (SPR) of Au NFs. At the same time, Au NFs provided a binding site for aptamer, which greatly improved the sensitivity of the constructed sensing platform. After the target chloramphenicol (CAP) was specifically captured by the aptamers on the electrode, the formed bioconjugates seriously hindered the transfer of electrons and the absorption of light and caused a reduced photocurrent. For the detection of CAP, this signal off type PEC aptasensor had a linear range of 5 pM-300 nM and a limit of detection of 49.9 fM (S/N = 3) with good stability, selectivity and reproducibility. Meanwhile, the method had satisfactory recovery results in the detection of CAP in real-life samples such as milk, tap water, honey and chloramphenicol eye drops.

Distyrylbenzene-based semi-conducting molecular material for OLED applications: Synthesis, characterization and TD-DFT calculations

New semi-conducting molecular materiel (M-DSB) based on the distyrylbenzene π-conjugated system was synthesized via the Wittig reaction. The structural properties of M-DSB, displaying three different stereoisomers E-E, Z-Z and Z-E, were investigated through density functional theory (DFT) optimization. The detailed TD-DFT analysis provided insights into the structure-property relationships and revealed good agreement with experimental data. This photoactive material exhibits nearly the same UV–visible spectra in dilute solution and as solid thin film, with a maximum absorption at 363 nm and an optical gap of 2.99 eV. A broad and red-shifted photoluminescence spectrum was obtained in the solid state with blue emission compared to the solution which shows purplish blue emission with relatively narrow emission. The HOMO/LUMO energy levels were calculated by cyclic voltammetry measurements and indicate a p-type semiconductor material. The temperature and frequency dependence of the conductivity shows an activation energy value of about 0.89 eV for the M-DSB thin layer. Impedance spectroscopy of the ITO/M-DSB/Al device indicates a typical behavior of a single relaxation process and confirms that the electrical response becomes faster and the mobility of the charge carriers is enhanced by increasing the temperature.

Regulating Phase Separation Kinetics for High-Efficiency and Mechanically Robust All-Polymer Solar Cells.

All-polymer solar cells (all-PSCs) possess excellent operation stability and mechanical robustness than other types of organic solar cells, thereby attracting considerable attention for wearable flexible electron devices. However, the power conversion efficiencies (PCEs) of all-PSCs are still lagging behind those of small-molecule-acceptor-based systems owing to the limitation of photoactive materials and unsatisfactory blend morphology. In this work, a novel terpolymer, denoted as PBDB-TFCl (poly4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)benzo[1,2-b:4,5-b″]dithiophene-1,3-bis(2-ethylhexyl)-5,7-di(thiophen-2-yl)-4H,8H-benzo[1,2-c:4,5-c″]dithiophene-4,8-dione-4,8-bis(4-chloro-5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene), is used as an electron donor coupled with a ternary strategy to optimize the performance of all-PSCs. The addition of PBDB-TCl unit deepens the highest occupied molecular orbital energy level, reducing voltage losses. Moreover, the introduction of the guest donor (D18-Cl) effectively regulates the phase-transition kinetics of PBDB-TFCl:D18-Cl:PY-IT during the film formation, leading to ideal size of aggregations and enhanced crystallinity. PBDB-TFCl:D18-Cl:PY-IT devices exhibit a PCE of 18.6% (certified as 18.3%), judged as the highest value so far obtained with all-PSCs. Besides, based on the ternary active layer, the manufactured 36 cm2 flexible modules exhibit a PCE of 15.1%. Meanwhile, the ternary PSCs exhibit superior photostability and mechanical stability. In summary, the proposed strategy, based on molecular design and the ternary strategy, allows optimization of the all-polymer blend morphology and improvement of the photovoltaic performance for stable large-scale flexible PSCs.

Superomniphobic and Photoactive Surface Presents Antimicrobial Properties by Repelling and Killing Pathogens.

Healthcare-acquired infections place a significant burden on the cost and quality of patient care in hospitals. Reducing contamination on surfaces within healthcare environments is critical for halting the spread of these infections. Herein, we report a bifunctional─repel and kill─surface developed using photoactive TiO2 nanoparticles integrated into a hierarchical scaffold (OmniKill). To quantify the repellency of OmniKill, we developed a touch-based assay, capable of simulating the transfer of individual pathogens, multiple pathogens, or pathogen-latent fecal matter from hands to surfaces. OmniKill repels bacterial pathogens by at least 2.77-log (99.8%). The photoactive material within OmniKill further reduces the viability of transferred pathogens on the surface by an additional 2.43-log (99.6%) after 1 h of light exposure. The antipathogenic effects─repel and kill─remain robust under complex biological contaminates such as feces. These findings show the potential use of OmniKill in reducing the physical transmission of bacterial pathogens in healthcare settings.