Zinc Oxide Microparticles Research Articles

Application of nano-TiO2 and micro-ZnO on cementitious surfaces for self-cleaning façades by spray coating and dip coating: A comparative study

Building façades are constantly exposed to atmospheric pollution and various external agents that can degrade their aesthetic qualities and introduce degradation patterns that affect the durability and performance of the materials. Façades with self-cleaning properties are important in the modern construction industry and the conservation of historic buildings, as they reduce costs and allow the preservation of original surfaces without the need for invasive interventions that could compromise cultural heritage. This study does a comparative analysis of the application of photocatalytic coatings composed of aqueous dispersions of titanium dioxide nanoparticles (TiO₂) and zinc oxide microparticles (ZnO) on cementitious substrates for use on façades by two functionalisation methods: spray coating and dip coating. A comprehensive characterisation was carried out using techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS) to assess the morphology, crystal structure and light absorption properties of the photocatalyst particles while Energy Dispersive Spectroscopy (EDS) and scanning electron microscopy (SEM) were employed to evaluate the substrate. The self-cleaning performance was evaluated by monitoring the degradation of Rhodamine B (RhB) dye under simulated sunlight. Spectrophotometric analysis was used to assess the colour coordinates using a standard colour system (CIELAB colour space). The results showed that the photocatalytic coatings improved the surfaces' self-cleaning properties while maintaining the substrate's original aesthetics. Spray-applied micro-ZnO-based coatings showed the most significant effectiveness in terms of self-cleaning.

Surface cleanliness of hydrothermally grown zinc oxide microparticles compared to commercial nanoparticles

Zinc oxide (ZnO) nanoparticles are attractive candidates for application as antibacterial agents due to their effectiveness against antibiotic-resistant strains of both gram-positive and gram-negative bacteria. Despite this potential, applications are limited by fundamental gaps in current understanding of their underlying antibacterial pathways. ZnO microparticles are less often used in antibacterial research compared to ZnO nanoparticles due to the potential of nanoparticles for internalization into bacterial cells. Microparticles are nevertheless of interest as a research platform as their increased scale allows both the nonpolar and polar faces of the ZnO crystals to be distinguished. This in turn provides a useful platform to study surface interactions with bacteria, allowing for more targeted investigation of antibacterial mechanisms. Previous preliminary studies have indicated that hydrothermally grown ZnO microparticles exhibit comparable antibacterial activity to commercial ZnO nanoparticles further adding to their utility. The purpose of this research was to examine the surface cleanliness of ZnO microparticles in comparison to nanoparticles utilizing both scanning electron microscopy (SEM) as well as Fourier transform infrared spectroscopy (FTIR). The results of our experiments supported our hypothesis that there were no significant differences in the surface contamination of ZnO microparticles compared to nanoparticles. This supports the usage of ZnO microparticles as a viable platform for studying antibacterial mechanisms observed at the nanoscale knowing that in the absence of internalization effects the mechanism of antibacterial action across scales is intrinsic to ZnO and not a result of differing surface cleanliness.

Green synthesis of zinc oxide microparticles using the leaf extract of Dolichandrone spathacea in sustainable agriculture: a new approach for protecting the legume plant (Vigna radiata) against the Cr(VI) stress

Green synthesis of zinc oxide microparticles using the leaf extract of Dolichandrone spathacea in sustainable agriculture: a new approach for protecting the legume plant (Vigna radiata) against the Cr(VI) stress

Detection of 4-nitrophenol in wastewater using microstructures of various morphologies

In the present study, zinc-oxides with three different morphologies were synthesized by the hydrothermal method. The products synthesized were examined adopting the EDX under the SEM, XRD, FT-IR and BET. The BET analysis results showed that the surface area of the ZnO-2 microparticles was substantially higher compared to the previously published[1,2]. These characterized zinc-oxides were evaluated for their catalytic role in the reduction of 4-NP to 4-AP, which is released into nature with wastewaters as a result of industrial production and poses a threat to the environment and living organisms. A change was also observed in the reduction efficiency of 4-NP to 4-AP by changing the morphology and surface area of the zinc-oxide microparticles. According to the BET analysis result, the rate constant for the reduction reaction of 4-NP was found to be 4.5 × 10−3s−1 in the presence of the ZnO-2 catalyst in the microsheet-structure with the largest surface area, while the recycling was found to be 97.49%. ZnO-2 exhibits excellent catalytic performance, better than the others. As a result, it was revealed that the increase in the surface area of the ZnO microparticles had a positive effect on the catalytic performance. The present study is a guiding study for wastewater treatment applications.

Development of jellyfish-like ZnO@Ag substrate for sensitive SERS detection of melamine in milk

Melamine has received enormous attention because of being illegally adulterated into milk, posing potential threats to human health. It is vital for developing sensitive analytical methods for detecting melamine in milk at the lowest possible concentration. In this context, we proposed a highly sensitive surface-enhanced Raman scattering (SERS) substrate based on hybridization of jellyfish-like zinc oxide microparticles and silver nanoparticles (JF ZnO@Ag) for detecting melamine in milk. The JF ZnO with a rough surface facilitates the deposition of Ag nanoparticles and adsorbing analytes, providing the abundant “hot spots” for the electromagnetic enhancement and the suitable charge transfer path to induce the chemical enhancement. Using the rhodamine 6G (R6G) as the Raman probe, the enhancement factor is as high as 7.58 × 106. As a real application, the substrate was successfully utilized in the detection of melamine in milk. The limit of detection (LOD) was down to 0.098 ppm, which is lower than the safety limit in the USA (2.5 ppm). The results manifest that the proposed substrate is an effective strategy to be applied as an analytical platform for the efficient detection of melamine in milk.

3D Printing Manufacturing of Polydimethyl-Siloxane/Zinc Oxide Micro-Optofluidic Device for Two-Phase Flows Control

Tailored ZnO surface functionalization was performed inside a polydimethyl-siloxane (PDMS) microchannel of a micro-optofluidic device (mofd) to modulate its surface hydrophobicity to develop a method for fine tuning the fluid dynamics inside a microchannel. The wetting behavior of the surface is of particular importance if two different phases are used for system operations. Therefore, the fluid dynamic behavior of two immiscible fluids, (i) air–water and (ii) air–glycerol/water in PDMS mofds and ZnO-PDMS mofds was investigated by using different experimental conditions. The results showed that air–glycerol/water fluid was always faster than air–water flow, despite the microchannel treatment: however, in the presence of ZnO microstructures, the velocity of the air–glycerol/water fluid decreased compared with that observed for the air–water fluid. This behavior was associated with the strong ability of glycerol to create an H-bond network with the exposed surface of the zinc oxide microparticles. The results presented in this paper allow an understanding of the role of ZnO functionalization, which allows control of the microfluidic two-phase flow using different liquids that undergo different chemical interactions with the surface chemical terminations of the microchannel. This chemical approach is proposed as a control strategy that is easily adaptable for any embedded micro-device.

Epoxy Composites Reinforced with ZnO from Waste Alkaline Batteries.

The zinc alkaline battery is one of the most popular sources of portable electrical energy, with more than 300,000 tons being consumed per year. Accordingly, it is critical to recycle its components. In this work, we propose the use of zinc oxide (ZnO) microparticles recovered from worn-out batteries as fillers of epoxy resins. These nanocomposites can be used as protective coatings or pigments and as structural composites with high thermal stability. The addition of ceramic nanofillers, such as ZnO or/and TiO2, could enhance the thermal and mechanical properties, and the hardness and hydrophobicity, of the epoxy resins, depending on several factors. Accordingly, different nanocomposites reinforced with recycled ZnO and commercial ZnO and TiO2 nanoparticles have been manufactured with different nanofiller contents. In addition to the different ceramic oxides, the morphology and size of fillers are different. Recycled ZnO are“desert roses” such as microparticles, commercial ZnO are rectangular parallelepipeds nanoparticles, and commercial TiO2 are smaller spherical nanoparticles. The addition of ceramic fillers produces a small increase of the glass transition temperature (<2%), together with an enhancement of the barrier effect of the epoxy resin, reducing the water diffusion coefficient (<21%), although the maximum water uptake remains constant. The nanocomposite water absorption is fully reversible by subsequent thermal treatment, recovering its initial thermomechanical behavior. The water angle contact (WCA) also increases (~12%) with the presence of ceramic particles, although the highest hydrophobicity (35%) is obtained when the epoxy resin reinforced with recycled flowerlike ZnO microparticles is etched with acid stearic and acetic acid, inducing the corrosion of the ZnO on the surface and therefore the increment of the surface roughness. The presence of desert rose ZnO particles enhances the de lotus effect.

Functionalized zinc oxide microparticles for improving the antimicrobial effects of skin-care products and wound-care medicines.

ZnO is an important component in skin-protection products and wound-care medicines. However, ZnO's antibacterial activity is moderate. We developed two types of ZnO microparticles loading with phthalocyanine-type photosensitizers (ZnO/PSs) introducing the photodynamic effects. These photosensitive ZnO microparticles exhibited long-term while moderate antimicrobial effects by continuously releasing Zn2+ ions. The antimicrobial efficacies were remarkably enhanced by triggering the photodynamic antimicrobial effects. Compared to the sole ZnO which showed non-measurable antimicrobial activity at a concentration of 10mg/L, both ZnO/PSs demonstrated antimicrobial rates ranged 99%-99.99% against Escherichia coli, normal and drug-resistant Staphylococcus aureus. In a dorsal wound infection mouse model, treatment with ZnO/PSs significantly accelerated the wound recovery rates. ZnO/PSs promoted wound healing by a dual effect: 1) the release of Zn2+ ions from ZnO facilitating tissue remodeling; 2) the photodynamic effect efficiently eliminates pathogens avoiding infection. Notably, ZnO/PSs inherited the high biosafety of ZnO without causing noticeable toxicity against erythrocyte and endothelial cells. This study not only provides a highly safe and efficient antimicrobial ZnO material for skin cares and wound modulations, but also proposes a strategy to functionalize ZnO materials.

Organic Template‐Free Synthesis of Mesoporous ZnO Microparticles by Sol‐Gel Method and Low‐Temperature Hydrothermal Treatment

Mesoporous zinc oxide microparticles were synthesized by the sol‐gel method, followed by hydrothermal treatment at three different temperatures (100°C, 120°C, and 140°C), confirming that the method is fast, simple, reproducible, and ecological. To carry out the synthesis of the samples, zinc acetate was used as a precursor and sodium hydroxide as a precipitating agent. From the results obtained, the sample that shows the highest mesoporosity was the one synthesized at a hydrothermal treatment temperature of 140°C, obtaining an average particle size of 5 μm and a pore diameter of 1.7 nm. The importance of the results obtained was that mesoporous xerogel microparticles were obtained without using any type of organic template.

Ultrasound Triggered ZnO‐Based Devices for Tunable and Multifaceted Biomedical Applications

AbstractSmart materials able to respond to an external stimulus or an environmental condition represent milestone developments in modern medicine. Among them, zinc oxide (ZnO) is a highly intriguing inorganic material with versatile morphologies/shapes and multifunctional properties like piezoelectricity, enhanced reactive oxygen species (ROS) generation, and antimicrobial ones. Here, the fabrication of smart ZnO‐based films is shown that can remotely be activated by ultrasound (US). US exposure induces electrical potentials on the fabricated devices that can be exploited to stimulate electrically responsive cells or promote ROS generation for cancer treatment. ZnO microparticles with surface nanostructuring are thus synthesized and processed in the form of a paste to deposit thin films on flexible polymeric supports. ZnO paste formulation and the fabrication procedure of the final device are optimized in terms of uniformity, hydrophilicity, and purity. Graphene oxide and poly(2‐hydroxyethyl methacrylate) are also layered onto the ZnO films in order to provide the devices with additional functionalities. ROS generation and electro‐mechanical performances upon US stimulation are evaluated for all of the developed devices. Finally, biocompatibility studies are conducted with osteoblast‐like cell cultures for possible applications in the contexts of bone tissue engineering/therapy.

Nano/microparticles in conjunction with microalgae extract as novel insecticides against Mealworm beetles, Tenebrio molitor

The intensive use of insecticides in global agricultural production has attracted much attention due to its many adverse effects on human health and the environment. In recent years, the utilization of nanotechnology has emerged as a tool to overcome these adverse effects. The aim of this work was to test different microparticles (zinc oxide (ZnO MPs) and silicon dioxide microparticles (SiO2 MPs)), and silver nanoparticles (Ag NPs) and to study their toxicity on a model organism, Tenebrio molitor. A comprehensive comparative study, which included more than a thousand mealworms divided into nine separate groups, was conducted. In addition to pure nano/microparticle solutions, the effect of particles mixed with the microalgae extract Chlamydomonas reinhardtii was also observed. Pure Ag NPs and SiO2 MPs resulted in larval mortality of more than 70% compared to that of pure ZnO MPs, in which the mortality rate was approximately 33%. A mixture of the algal extract with zinc oxide microparticles resulted in mortality that was double compared to that observed with pure ZnO MPs. In parallel, atomic absorption spectrometry (AAS) was used to determine the difference in the concentration of trace elements in the bodies of dead and live larvae.

A study on tribological behaviour and analysis of ZnO reinforced AA6061 matrix composites fabricated by stir casting route

PurposeThe most promising replacements for the industrial applications are particle reinforced metal matrix composites because of their good and combined mechanical properties. Currently, the need of matrix materials for industrial applications is widely satisfied by aluminium alloys. The purpose of this paper is to evaluate the tribological behaviour of the zinc oxide (ZnO) particles reinforced AA6061 composites prepared by stir casting route.Design/methodology/approachIn this study, AA6061 aluminium alloy matrix reinforced with varying weight percentages (3%, 4.5% and 6%) of ZnO particles, including monolithic AA6061 alloy samples, is cast by the most economical fabrication method, called stir casting. The prepared sample was subjected to X-ray photoelectron spectroscopy (XPS) analysis, experimental density measurement by Archimedian principle and theoretical density by rule of mixture and hardness test to investigate mechanical property. The dry sliding wear behaviour of the composites was investigated using pin-on-disc tribometer with various applied loads of 15 and 20 N, with constant sliding velocity and distance. The wear rate, coefficient of friction (COF) and worn surfaces of the composite specimens and their effects were also investigated in this work.FindingsXPS results confirm the homogeneous distribution of ZnO microparticles in the Al matrix. The Vickers hardness result reveals that higher ZnO reinforced (6%) sample have 34.4% higher values of HV than the monolithic aluminium sample. The sliding wear tests similarly show that increasing the weight percentage of ZnO particles leads to a reduced wear rate and COF of 30.01% and 26.32% lower than unreinforced alloy for 15 N and 36.35% and 25% for 20 N applied load. From the worn surface morphological studies, it was evidently noticed that ZnO particles dispersed throughout the matrix and it had strong bonding between the reinforcement and the matrix, which significantly reduced the plastic deformation of the surfaces.Originality/valueThe uniqueness of this work is to use the reinforcement of ZnO particles with AA6061 matrix and preparing by stir casting route and to study and analyse the physical, hardness and tribological behaviour of the composite materials.

Biodegradation and Antimicrobial Properties of Zinc Oxide–Polymer Composite Materials for Urinary Stent Applications

Research advancements in the field of urinary stents have mainly been in the selection of materials and coatings to address commonly faced problems of encrustation and bacterial adhesion. In this study, polylactic acid (PLA) and polypropylene (PP) were evaluated with zinc oxide (ZnO) coating to assess its ability to reduce or eliminate the problems of encrustation and bacteria adhesion. PLA and PP films were prepared via twin screw extrusion. ZnO microparticles were prepared using sol-gel hydrothermal synthesis. The as-prepared ZnO microparticles were combined in the form of a functional coating and deposited on both polymer substrates using a doctor blade technique. The ZnO-coated PP and PLA samples as well as their uncoated counterparts were characterized from the physicochemical standpoints, antibacterial and biodegradation properties. The results demonstrated that both the polymers preserved their mechanical and thermal properties after coating with ZnO, which showed a better adhesion on PLA than on PP. Moreover, the ZnO coating successfully enhanced the antibacterial properties with respect to bare PP/PLA substrates. All the samples were investigated after immersion in simulated body fluid and artificial urine. The ZnO layer was completely degraded following 21 days immersion in artificial urine irrespective of the substrate, with encrustations more evident in PP and ZnO-coated PP films than PLA and ZnO-coated PLA films. Overall, the addition of ZnO coating on PLA displayed better adhesion, antibacterial activity and delayed the deposition of encrustations in comparison to PP substrates.

Role of the paramagnetic donor-like defects in the high n-type conductivity of the hydrogenated ZnO microparticles

The magnetic and electronic properties of the hydrogenated highly conductive zinc oxide (ZnO) microparticles were investigated by electron paramagnetic resonance (EPR) and contactless microwave (MW) conductivity techniques in the wide temperature range. The EPR spectra simulation allowed us to resolve four overlapping EPR signals in ZnO microparticles. The Lorentzian EPR line with isotropic g-factor 1.9623(5) was related to the singly ionized oxygen vacancy. Another Lorentzian line with g|| = 1.9581(5), g⊥ = 1.9562(5) was attributed to the zinc interstitial shallow donor center, while EPR signal with g|| = 1.9567(5), g⊥ = 1.9556(5) and Gaussian lineshape was assigned to the hydrogen interstitial shallow effective-mass-like donor. The EPR signal with g|| = 1.9538(5), g⊥ = 1.9556(5) and Lorentzian lineshape was tentatively attributed to the shallow donor center. The charge transport properties in ZnO microparticles have been investigated by the contactless MW conductivity technique at T = 5–296 K. Two conduction mechanisms, including ionization of electrons from the shallow donors to the conduction band and hopping conduction process, have been distinguished. The hopping conduction process follows Mott’s variable-range hopping T−1/4 law at T = 10–100 K. The evaluated values of the average hopping distance (15.86 Å), and hopping energy (1.822 meV at 40 K) enable us to estimate the donor concentration in the investigated ZnO microparticles as ~ 1018 cm−3.

Enhancing dielectric and piezoelectric properties of micro-ZnO/PDMS composite-based dielectrophoresis

This work aims to enhance the dielectric and piezoelectric properties of polydimethylsiloxane (PDMS) polymer filled with zinc oxide (ZnO) powders. Both ZnO nanoparticles and microparticles are used to prepare piezoelectric composites and a comparison of their dielectric responses is carried out. The experimental results reveal that a higher particle concentration gives rise to the increased dielectric permittivity of composites, especially when particles are aligned in the poling-direction-based dielectrophoretic process. Hence, the microparticles are chosen instead of the nano ones because the microscale facilitates the fabrication process of the composite, especially with high filler content. It also makes it possible to clearly record the movement of particles under alternating (AC) voltage application using optical microscopy. Significant improvement in the dielectric and piezoelectric behavior of the proposed composite has been successfully achieved via dielectrophoretic alignment of ZnO microparticles. This technique leads to increased connectivity between ZnO/ZnO interfaces, allowing for the creation of continuous aligned piezoelectric particles inside the polymer matrix. As a result, the piezoelectric effect is considerably boosted. Finally, the dielectric constant, as well as the charge coefficient of the ZnO particles, is estimated through theoretical approaches for composites containing particles arranged in chains or randomly dispersed. The model predictions are in good agreement with the experimental results. Furthermore, a finite element model (FEM) is developed using Comsol Multiphysics to evaluate these parameters in a 3D structure, which is then compared to those obtained by the above 2D-analytic models.

Pullulan mediated zinc oxide microparticles: Effect of synthesis temperature

Zinc oxide (ZnO) has been gaining a lot of attention compared to the other semiconductor metal oxide. This is due to their favourable properties such as chemical stability, high electrochemical coupling coefficient, broad range of absorption radiation and high photostability. It also has wide band gap energy (3.37 eV), large exciton-binding energy (60 meV) and high thermal and mechanical stability at room temperature. Besides these desirable properties, the synthesis of ZnO has been widely studied as it is easy to synthesized and its properties such as band gap, shape and size can be controlled through synthesis parameters and methods. In this study, zinc oxide microparticles (ZnO-MCs) is produced with pullulan as mediator via precipitation method. The effect of synthesis temperature on the properties of synthesized ZnO-MCs were also studied. Based on the result obtained, all synthesized ZnO-MCs exhibited hexagonal wurtzite structure. As the synthesis temperature increases, the particles morphology changes from large spherical shape to flower-like morphology. Furthermore, the particle size also decreases with increasing temperature. This result is supported by surface area and pore analysis where the surface area ranging from 6.22 to 22.78 m2 g−1 was obtained as the synthesis temperature increases. All these results indicate that synthesis method and parameters will affect the properties of synthesized ZnO-MCs.

Transparent ZnO-coated polydimethylsiloxane-based material for photocatalytic purification applications

We describe production and photocatalytic properties of a material based on polydimethylsiloxane (PDMS) as a carrier substrate coated with microparticles of zinc oxide (ZnO). The ZnO microparticles are fabricated by our original hydrothermal method and intentionally have a defect structure. According to our understanding, this peculiar defect structure contributes to the greatly enhanced photocatalytic properties of the ZnO material. The resulting photocatalyst demonstrates high activity under visible light (410 nm) in the process of phenol degradation in water solution, while generally ZnO is inactive below the UV range. In addition, we compare the photocatalytic activity of our ZnO/PDMS composite to that of the same ZnO powder suspension in a similar setup. We find that the same activity is achieved by three orders of magnitude smaller amount of ZnO in our composite compared to the powder suspension. The ZnO/PDMS interface exhibits sufficiently strong bonding for stable operation that is ensured during material production. The obtained photocatalytic material preserves the transparency of PDMS due to the low amount of attached ZnO (about 0.1% by mass). The transparency of the photocatalytic ZnO/PDMS material enables easy performance upgrades by constructing multilayer or manifold fluid treatment devices.

Dye-Doped ZnO Microcapsules for High Throughput and Sensitive Optofluidic Micro-Thermometry.

The main objective of this work is to show the proof of concept of a new optofluidic method for high throughput fluorescence-based thermometry, which enables the measure of temperature inside optofluidic microsystems at the millisecond (ms) time scale (high throughput). We used droplet microfluidics to produce highly monodisperse microspheres from dispersed zinc oxide (ZnO) nanocrystals and doped them with rhodamine B (RhB) or/and rhodamine 6G (Rh6G). The fluorescence intensities of these two dyes are known to depend linearly on temperature but in two opposite manner. Their mixture enables for the construction of reference probe whose fluorescence does not depend practically on temperature. The use of zinc oxide microparticles as temperature probes in microfluidic channels has two main advantages: (i) avoid the diffusion and the adsorption of the dyes inside the walls of the microfluidic channels and (ii) enhance dissipation of the heat generated by the focused incident laser beam thanks to the high thermal conductivity of this material. Our results show that the fluorescence intensity of RhB decreases linearly with increasing temperature at a rate of about −2.2%/°C, in a very good agreement with the literature. In contrast, we observed for the first time a nonlinear change of the fluorescence intensity of Rh6G in ZnO microparticles with a minimum intensity at a temperature equal to 40 °C. This behaviour is reproducible and was observed only with ZnO microparticles doped with Rh6G.

Heparin‐Mediated Growth of Self‐Organized ZnO Quasi‐Microspheres with Twinned Donut‐Like Hierarchical Structures

AbstractThe insight into the rational design of nanostructure with complex functionality is a significant challenge for the advanced application of Zinc Oxide (ZnO) in various areas. Herein, heparin, as a biotemplate, was introduced to manipulate growth of ZnO nanoparticle into hierarchical structures with unusual morphology. The formation process of the morphology and microstructure of the as‐achieved products were investigated. The heparin could alter nucleation and growth rates during the primary nanocrystal formation of ZnO, and promote the formation of two‐dimensional nanoplates and subsequently self‐assembly into novel quasi‐microspherical ZnO superstructures with twinned donut‐like hemispheres. The self‐assembled quasi‐microspheres displayed well crystallinity with a hexagonal wurtzite structure and a nearly uniform size‐distribution with a value of 452.9 ± 51.2 nm. The concentrations of heparin and zinc precursor played a vital role in determining the morphology of the resulting products. The possible growth mechanism of the obtained spherical like ZnO microparticles was proposed and discussed in detail. Our results are of fundamental importance to understanding crystal growth, and beneficial to promote the potential applications of ZnO with novel hierarchical structures in nanoscale devices.

ZnO decorated laser-induced graphene produced by direct laser scribing.

A scalable laser scribing approach to produce zinc oxide (ZnO) decorated laser-induced graphene (LIG) in a unique laser-processing step was developed by irradiating a polyimide sheet covered with a Zn/ZnO precursor with a CO2 laser (10.6 μm) under ambient conditions. The laser scribing parameters revealed a strong impact on the surface morphology of the formed LIG, on ZnO microparticles' formation and distribution, as well as on the physical properties of the fashioned composites. The ZnO microparticles were seen to be randomly distributed along the LIG surface, with the amount and dimensions depending on the used laser processing conditions. Besides the synthesis conditions, the use of different precursors also resulted in distinct ZnO growth's yields and morphologies. Raman spectroscopy revealed the existence of both wurtzite-ZnO and sp2 carbon in the majority of the produced samples. Broad emission bands in the visible range and the typical ZnO near band edge (NBE) emission were detected by photoluminescence studies. The spectral shape of the luminescence signal was seen to be extremely sensitive to the employed processing parameters and precursors, highlighting their influence on the composites' optical defect distribution. The sample produced from the ZnO-based precursor evidenced the highest luminescence signal, with a dominant NBE recombination. Electrochemical measurements pointed to the existence of charge transfer processes between LIG and the ZnO particles.