Spin-coating Procedure Research Articles

Reliable fabrication of 3D freestanding nanostructures via all dry stacking of incompatible photoresist

Three-dimensional (3D) free-standing nanostructures based on electron-beam lithography (EBL) have potential applications in many fields with extremely high patterning resolution and design flexibility with direct writing. In numerous EBL processes designed for the creation of 3D structures, the multilayer resist system is pivotal due to its adaptability in design. Nevertheless, the compatibility of solvents between different layers of resists often restricts the variety of feasible multilayer combinations. This paper introduces an innovative approach to address the bottleneck issue by presenting a novel concept of multilayer resist dry stacking, which is facilitated by a near-zero adhesion strategy. The poly(methyl methacrylate) (PMMA) film is stacked onto the hydrogen silsesquioxane (HSQ) resist using a dry peel and release technique, effectively circumventing the issue of HSQ solubilization by PMMA solvents typically encountered during conventional spin-coating procedures. Simultaneously, a dry lift-off technique can be implemented by eschewing the use of organic solvents during the wet process. This pioneering method enables the fabrication of high-resolution 3D free-standing plasmonic nanostructures and intricate 3D free-standing nanostructures. Finally, this study presents a compelling proof of concept, showcasing the integration of 3D free-standing nanostructures, fabricated via the described technique, into the realm of Fabry-Perot cavity resonators, thereby highlighting their potential for practical applications. This approach is a promising candidate for arbitrary 3D free-standing nanostructure fabrication, which has potential applications in nanoplasmonics, nanoelectronics, and nanophotonics.

Structural and optical properties of ZnO thin films as a function of pH value and its effect on photoelectrochemical water splitting

ZnO nanoparticles were synthesised via sol–gel method, and then, deposited on a glass substrate using the spin-coating procedure to hand in ZnO thin films. In order to study the effect of alkaline sol on different properties of ZnO thin films, the pH value of sol was adjusted with ammonia. Then, the structural, optical, and photoelectrochemical properties of the prepared samples were analysed. According to XRD analyses, by increasing pH values, the size of ZnO particles increases and the films’ crystallinity improves. In addition, SEM micrographs affirm the uniformity of thin films. According to AFM findings, the morphology and roughness of the samples’ surface are affected by pH values in such a way that with increasing the pH, the roughness of the surface decreases, and the crystallinity improves. Also, both UV–vis peaks shift towards lower wavelengths with increasing pH value of ZnO sol. This means that the more the pH values of ZnO sol, the more the excitation energy of electrons. On the other hand, the numerical values of the energy bandgap decrease by increasing pH. According to PL results, the increase of pH causes the separated electrons and holes to have more energy and can move away from each other. So, the recombination process rate decreases; this result affirms by EIS findings. Increasing the optical absorption and reducing charge recombination are in favour of the photocatalytic reactions. Clearly, increasing the pH value causes the stable photocurrent to increase and the threshold voltage of (J-V) diagram to decrease. Also, the samples show recognisable sensitivity to light. As a final result, the best suggested amount of pH to fabricate ZnO photoanods for water splitting is 10.5.

Silver-modification of ZnO thin films deposited on Zn-electroplated Cu substrate by thermal shock method for the enhanced photocatalytic performance

Ag-modified ZnO thin films on Zn-electroplated Cu substrate with different Ag-contents were prepared via a simple sol–gel spin-coating procedure followed by a thermal shock method with AgNO3, and then characterized by XRD, Raman, FTIR, FESEM, EDX, and UV-visible absorption spectroscopy. Their photocatalytic performance was evaluated by the degradation of methylene blue. Due to the sol–gel spin-coating process, the film was successfully immobilized on mechanically robust Zn/Cu plates, making it promising for applications in harsh practical conditions and facilitating recovery. When our ZnO thin films were surface-modified with AgNO3 at 1 and 2 mol%, they exhibited the best photocatalytic activity under UVA light and visible light, respectively, which can be explained by the appearance of maze-like architecture on their surface with vertical ZnO walls, surface defects and metallic silver nanoparticles. However, when the Ag-content was increased to 3 mol%, the maze-like structure collapsed, leading to decreases in photocatalytic performance.

Effects of La Doping on Local Structure of Hafnium Oxide Studied by X-Ray Absorption Spectroscopy

HfO2-based films prepared by the integration of the sol-gel method and spin-coating procedure were used as the study system to investigate the influence of La doping by varying the La contents of 20, 40, 50, and 60 wt%. GIXRD, XANES, and EXAFS measurements were performed to analyze phase formation, crystal structure, and local structure of the films. The XANES data of the Hf L3 -edge show no significant difference with respect to an increase in La content, indicating a considerable stability of the hafnium ion in the +4 oxidation state. Moreover, the EXAFS spectrum shows that the coordination number of Hf4+ is seven and the Hf–O bond length is ∼2.11 Å, which additionally confirms the formation of monoclinic HfO2 structure. The contributions of the second coordination shells, which are assigned to the Hf–Hf and Hf–La bonds, become well-structured with increasing La concentration in the HfO2 structure. However, the study suggests that the La-doped concentration affects the phase transformation from monoclinic to tetragonal and finally orthorhombic phase, leading to the presence of ferroelectric materials.

Development of a visible-light-active-NiTiO3 coating for the efficient removal of the persistent herbicide 2,6-dichlorobenzamide (BAM) from drinking water

In the present research work, the photocatalytic evaluation of NiTiO3 nanoparticles immobilized on glass plates by the spin-coating procedure was carried out in the degradation of the recalcitrant herbicide 2,6-dichlorobenzamide (BAM). The concentrations of Ni employed to synthesize NiTiO3 nanoparticles were 1 wt% (1TESNi) and 2 wt% (2TESNi). The stability of coatings was evaluated by several washings and thermal treatments, which were verified by UV–vis analyses. The morphology of the coatings was studied by scanning electron microscopy (SEM-EDS). The coatings displayed thickness values of 1.35 and 2.56 μm for TiO2 and 1TESNi, respectively. The crystalline phases of the coatings were analyzed by X-ray diffraction (XRD), confirming the presence of NiTiO3 and other phases related to TiO2. The bandgap of 1TESNi, compared with the bare TiO2, was reduced from 2.96 to 2.40 eV as a consequence of Ni addition. The TiO2, 1TESNi and 2TESNi coatings were evaluated in the photodegradation of BAM using visible-light for 240 min. The highest effectiveness was displayed by the 1TESNi coating, obtaining degradation of 92.56% after 240 min. Also, the photocatalytic efficiency of the 1TESNi coating was only reduced 1.99% after 3 reuse cycles in the BAM degradation. The scavenger tests revealed that the main oxidizing species involved in the reaction were the •OH− and •O2− radicals. The 1TESNi coating showed the highest photocatalytic efficiency because of its absorption in the visible-light region, valuable surface area and electronic charge separation. Thus, these advantageous features guarantee that NiTiO3 coatings are an efficient method for degrading recalcitrant herbicides from drinking water using a practical way to recover and reuse photocatalysts.

Aprotic Solvent Effect in Preparation of Organo Lead Iodide Perovskite Nanowires by Two-Step Spin-Coating Procedure

Lead-iodide perovskite (CH3NH3PbI3 ≡ MAPbI3) nanowires (NWs) were prepared by a two-step spin-coating technique by modifying one of the perovskite precursors with a small amount of aprotic solvent. In the two-step spin-coating technique, the perovskite precursors are MAI and PbI2. The first MAI powder is dissolved in isopropanol (IPA) to produce an isopropanol-MAI solution, while the second PbI2 is used in N, N-dimethylformamide (DMF) as an aprotic solvent. Here, a small amount of DMF was used with an IPA solution of MAI to grow 1D NWs based on MAPbI3 perovskite. Then, the film was formed directly from the MAPbI3 perovskite nanowires (PNWs) by coating the PbI2 layer with an IPA solution of MAI modified by DMF. The amount of DMF in the MAI/IPA solution was adjusted in the range between 0 and 50 μl. One-dimensional (1D) PNWs (∼100 nm diameter) and three-dimensional (3D) perovskite nanocrystals are compared. The structural and optical properties of the PNWs films are systematically investigated using X-ray diffraction patterns (XRD), scanning electron microscopy images (SEM), UV–vis absorption, and photoluminescence (PL). The result is that the presence of an additional solvent and its optimized amount in the MAI/IPA solution can increase the length and efficiency of charge transfer by facilitating perovskite transformation, as evidenced by the intensity of PL and the formation of a high-quality perovskite film. Compact, hole-free films with low trap states (crystal defects) were obtained. Further investigation of the lead iodide perovskite showed that reducing the dimensionality from 3D to 1D resulted in shorter wavelengths of the absorption edge and the PL peak in both the absorption and PL spectra. The shorter wavelengths indicate more localized exciton states in NWs. Finally, the amplified spontaneous emission (ASE) properties were obtained under picosecond laser excitation and a low ASE threshold was found at 10 and 53 μJ/cm2 for 1D and 3D, respectively, at about 300 nm film thickness.

Addition of en-APTAS to a Polythiophene Film for Enhanced NO2 Gas Sensing

With the aim of enhancing gas-sensor performance, we introduced N-[3-(trimethoxysilyl)propyl]ethylenediamine (en-APTAS) into poly(3-hexylthiophene) (P3HT) thin films. The P3HT films with en-APTAS as an additive showed superior gas-sensing performance compared with pristine P3HT films. The sensitivity of the gas sensor with en-APTAS was especially enhanced for NO2 gas because the en-APTAS has two amine groups that act as adsorption sites for NO2 gas molecules as a consequence of their strong binding energy. The P3HT film with 0.5 vol % en-APTAS fabricated on a OH-functionalized substrate exhibited the greatest responsivity (ΔID/I0 = 0.83) and highest response, recovery rates (ΔR/Δt = 0.26 and 0.004, respectively), and sensitivity (2.9%/ppm) among the investigated films. The superior performance of this film is attributed to the en-APTAS coupling-agent additive in the P3HT active layer concomitantly modifying the OH-functionalized substrate via a one-step spin-coating procedure. The increase in the abundance of adsorption sites in the channel region can induce more p-doping by NO2, leading to an increase of the hole carrier density and, thus, an increase of the current level in a p-type transistor gas sensor.

Bio-inorganic hybrid structures for direct electron transfer to photosystem I in photobioelectrodes

Synthetic materials can be combined with biological components in many ways. One example that provides scientists with multiple challenges is a photobioelectrode that converts sunlight into electrons in a biohybrid approach. In the present study several key parameters are evaluated concerning their influence on the direct electron transfer from a 3D indium tin oxide (ITO) electrode material to photosystem I (PSI) as a light-harvesting biomolecule. In contrast to previous investigations, no mediating molecule is added to shuttle the electrons to the luminal side of PSI. Thus, this setup is less complex than foregoing ones. The solution composition drastically influences the interaction of PSI with the ITO surface. Here, the application of higher buffer concentrations and the addition of salts are advantageous, whereas the nature of the buffer ions plays a minor role. The artificial electrode material's thickness is adjustable since a spin-coating procedure is used for preparation. With a 30 μm thick structure and immobilized PSI cathodic photocurrents up to 10.1 μA cm−2 are obtained at 100 mW cm−2 illumination intensity and an applied potential of −0.1V vs. Ag/AgCl. Over a period of three days the photobioelectrodes are illuminated for a total of 90 min and stored between the measurements at ambient temperature. The stability of the setup is noteworthy as still about 90% of the photocurrent is retained. The photocathode described here offers many positive features, including a high onset potential for the photocurrent starting sligthly above the redox potentail of P700, and applicability in a wide pH range from pH 5 to 8.

Ultrathin polyamide membranes enabled by spin-coating assisted interfacial polymerization for high-flux nanofiltration

While nanofiltration (NF) membranes have much potential for precise molecule/ion separations, the thick nanofilms fabricated via rapid and irreversible interfacial polymerization (IP) result in low water permeance. The distribution and location of aqueous monomers play a pivotal role in the IP reaction and thus in the polyamide films, yet are rarely reported to improve the performance. In this study, a one-step spin-coating procedure was utilized to deposit diamines atop porous polysulfone substrates followed by IP reaction for construction of ultrathin polyamide membranes. Direct spin-coating of aqueous diamines onto a porous substrate allows for a uniform diamine deposition, demonstrated by confocal laser scanning microscope analysis. In addition to the uniform distribution, this procedure is able to enrich the diamines beyond the surface pores, contributing to the formation of ultrathin polyamide layers based on Freger’s theory. Importantly, rational regulation of spinning speed, aqueous phase volume, and IP reaction parameters allows to optimize the membrane microstructure and separation performance. The optimal TFC membranes with 9.7-nm-thick polyamide nanofilm evince a remarkably high water permeance of 36.1 L m-2 h−1 bar−1, and an acceptable divalent Na2SO4 rejection of 96.2%. An extended use of spin-coating assisted IP onto other substrates also yields high-flux polyamide NF membranes (TFC-Kevlar: 37.9 L m-2 h−1 bar−1, 97.5%, TFC-polyacrylonitrile: 41.7 L m-2 h−1 bar−1, 96.2%), confirming the applicability and high efficiency of this approach. In contrast with established methods, spin-coating assisted IP (SCIP) features distinct superiorities in economizing diamine dosage, ease of control, and attaining an excellent sieving performance, which paves the way of constructing high-performance NF membranes.

Mass production of self-passivated perovskite microlaser particles by solution-phase processing for gas sensors

Developing mass-productive and high-performance microlaser particles (MLPs) by cost-effective approaches is highly promising for MLP-based optoelectronic applications, which remains a daunting challenge. Herein, we develop a novel solution-phase technique to realize the halide perovskite-based MLPs in a scalable manner. By regulating the dynamic process of crystallization in a two-step spin-coating procedure, the large-scale CsPbBr3 microcrystals are acquired. Importantly, the solution-processed CsPbBr3 microcrystals exhibit much stronger emission than the ones prepared by the chemical vapor deposition method, which is attributed to the low carrier trap density by the formation of a self-passivated and bromine-rich surface. These CsPbBr3 microcrystals with inverted pyramid morphology are demonstrated to support the whispering-gallery mode lasing, featuring low pump threshold and high Q-factor. Moreover, the technologically important single-mode lasing is achieved from the sub-5 μm-sized MLPs, thanks to the superior optical property. Eventually, the laser-emission-based gas sensor is demonstrated. These results represent a significant step toward scalable MLPs and related applications.

Template Stripping of Perovskite Thin Films for Dry Interfacing and Surface Structuring.

Combining excellent optoelectronic properties with the benefits of solution processability, metal-halide perovskites are promising materials for photovoltaic and light-emitting technologies. To facilitate the integration of perovskite thin films into optoelectronic devices, a need exists for simple and efficient fabrication methods. Here, we present a template-stripping technique to produce ultraflat and flexible perovskite thin films. We apply a one-step spin-coating procedure to produce high-quality CH3NH3PbBr3 perovskite thin films on top of ultraflat silicon templates. These films can be mechanically cleaved from the template using a polymer adhesive to reveal the ultraflat perovskite surfaces. We demonstrate how the flatness and flexibility of the template-stripped films enable new processing strategies based on dry interfacing, by interfacing them with plasmonic hole arrays. Moreover, we show that by using prepatterned silicon templates, structured perovskite surfaces can be produced with feature sizes down to a micrometer.

Simple Method for Efficient Slot-Die Coating of MAPbI3 Perovskite Thin Films in Ambient Air Conditions.

Scalable methods for deposition of lead halide perovskite thin films are required to enable commercialization of the highly promising perovskite photovoltaics. Here, we have developed a slot-die coating process under ambient conditions for methylammonium lead iodide (MAPbI3) perovskite on heated substrates (about 90 °C on the substrate surface). Dense, highly crystalline perovskite films with large grains (100–200 μm) were obtained by careful adjustment of the deposition parameters, using solutions that are similar but more dilute than those used in typical spin-coating procedures. Without any further after treatments, such as antisolvent treatment or vapor annealing, we achieved power conversion efficiencies up of 14.5% for devices with the following structure: conducting tin oxide glass (FTO)/TiO2/MAPbI3/spiro-MeOTAD/Au. The performance was limited by the significant roughness of the deposited films, resulting from the hot-casting method, and the relatively high deposition temperature, which led to a defect-rich surface due to loss of MAI.

Hole-Transporting Organic Salt Induced Surface-2D/Bulk-3D Hierarchy Perovskite for Efficient and Stable Photovoltaic Devices

Here, we report a novel hole-transporting organic salt (HTOS) based on (4'-(bis(4-methoxyphenyl)amino)-[1,1'-biphenyl]-4-yl)methanaminium bromide, which facilely forms a hole-transporting 2D perovskite on the top surface of 3D perovskite via a spin-coating procedure. This capping 2D perovskite can significantly reduce interface trap densities and enhance hole-extracting abilities of heterojunction region between 3D perovskite and hole-transporting layer (HTL), owing to its spatially and potentially confined hole-charge carriers, simultaneously. This interfacial HTOS induced 2D perovskite can effectively suppress nonradiative recombination, which leads to an increase in the photovoltage of perovskite solar cells (PSC) to more than 1.20 V. As a result, the n-i-p planar PSC can achieve a champion power conversion efficiency of 20.71% as well as excellent operational stability exhibiting 92% of initial efficiency after 500 h continuous illumination without encapsulation. This work provides a facile approach to fabricate hole-transporting surface-2D and light-harvesting bulk-3D hierarchy perovskite structure, which delivers significantly enhanced efficiency and stability of PSCs.

Structural, Morphological and Electrical Properties of CdO Thin Film Produced by Sol–Gel Spin Coating Procedure

A sol–gel spin coating procedure was used to produce cadmium oxide (CdO) thin film on the precleaned glass substrate. The structural, morphological and electrical properties of the produced film were specified by XRD, SEM and two-probe method. The polycrystalline nature with cubical structure of the cadmium oxide (CdO) thin film was confirmed by X-ray diffraction (XRD). Scanning electron microscope (SEM) confirms the uniform formation of film. The semiconducting character of the film was confirmed by electrical conductivity (direct current) measurement in dark. The Hall effect measurement of cadmium oxide film confirms the n-type conductivity.

Silver-Doped Hydroxyapatite Thin Layers Obtained by Sol-Gel Spin Coating Procedure

The main objective of this paper is to develop silver-doped hydroxyapatite suspensions (HApAg) with different concentrations of silver (?Ag = 0.05 and ?Ag = 0.2) in order to obtain uniform and homogenous layers by spin-coating procedure. The colloidal properties of HApAg suspensions are evaluated by dynamic light scattering (DLS) analysis, ζ-potential (ZP), and ultrasound measurements. The ultrasound studies show that the HApAg20 sample revealed better stability than the HApAg5 sample. The structural and morphological analysis on suspensions and thin layers is also conducted. It is observed that the particles of the two samples have a similar shape and are uniform. The layers obtained present a homogeneous appearance of the surface without evidence of cracks or interruption of the coatings. The in vitro antifungal studies conducted on the two thin layers at two different time intervals (24 and 48 h) show that both HApAg5 (?Ag = 0.05) and HApAg20 (?Ag = 0.05) nanoparticles suspensions and composite layers inhibit the development of colony forming units (CFU) even after 24 h of incubation comparative to the control, represented by the Candida albicans (C. albicans) culture in a proper medium. The fungicidal effect was evident after 48 h of incubation in the case of both HApAg20 nanoparticles suspensions and composite layers.

Improving extraction efficiency of OLEDs by a luminescent polymer embedded in a colloidal crystal matrix

Here, it is reported an enhancement of the light-extraction efficiency in organic light emitting diodes (OLEDs) by growing a colloidal crystal (CC) matrix inside the luminescent layer of single bottom-emitting heterostructures. The CC matrix is obtained by self-assembly of Silica (SiO2) spheres during the spin-coating procedure used for the deposition of the luminescent polymer Poly [2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV). The SiO2 sphere diameter is estimated assuming a crystalline face-centered-cubic (fcc) structure and performing first principles calculations with the plane wave expansion method. The calculations provided a 250 nm sphere diameter for an adequate decoupling of the waveguide organic mode. From these considerations both, traditional bilayer and nanostructured OLEDs, were elaborated using ITO/PEDOT:PSS/MDMO-PPV/Ag and ITO/PEDOT:PSS/MDMO-PPV+Colloidal crystal/Ag architectures, respectively. The light-extraction efficiencies of both types of OLED architectures are quantified by measuring the wall plug efficiency. The results show a significant increase (near to 30%) on the average efficiency for nanostructured OLEDs. The improvement in the power efficiency is attributed to a reduction in the effective refractive index of the organic layer through the incorporation of a fcc-colloidal crystal into the emission layer (EML) of the OLED, which modifies their reflection properties. This novel method for obtaining CC in a single-step associated to the spin coating process has also the advantage of introducing the scattering medium directly into the EML in order to modify internal coupling modes, instead of focusing on substrate modification.

Conjugation-Curtailing of Benzodithionopyran-Cored Molecular Acceptor Enables Efficient Air-Processed Small Molecule Solar Cells.

Small molecule solar cells (SMSCs) lag a long way behind polymer solar cells. A key limit is the less controllable morphology of small molecule materials, which can be aggravated when incorporating anisotropic nonfullerene acceptors. To fine-tune the blending morphology within SMSCs, a π-conjunction curtailing design is applied, which produces a efficient benzodithionopyran-cored molecular acceptor for nonfullerene SMSCs (NF-SMSCs). When blended with a molecular donor BDT3TR-SF to fabricate NF-SMSCs, the π-conjunction curtailed molecular acceptor NBDTP-M obtains an optimal power conversion efficiency (PCE) of up to 10.23%, which is much higher than that of NBDTTP-M of longer π-conjunction. It retains 93% of the PCE of devices fabricated in a glove box when all spin-coating and post-treating procedures are conducted in ambient air with relative humidity of 25%, which suggests the good air-processing capability of π-conjunction curtailed molecules. Detailed X-ray scattering investigations indicate that the BDT3TR-SF:NBDTP-M blend exhibits a blend morphology featuring fine interpenetrating networks with smaller domains and higher phase purity, which results in more efficient charge generation, more balanced charge transport, and less recombination compared to the low-performance BDT3TR-SF:NBDTTP-M blend. This work provides a guideline for molecular acceptors' design toward efficient, low-cost, air-processed NF-SMSCs.

The preparation of Ag3BiBr6 films and their preliminary use for solution processed photovoltaics

Bismuth-halide-based perovskites could be promising candidates for construction of lead-free and air-stable perovskites solar cells. Herein we report a simple strategy on the fabrication of the Ag3BiBr6 thin films. They were prepared by flexible spin-coating procedure and the solvent of N-butylamine is found to be critical to dissolving AgBr precursor solution under lower room temperatures. Experiment and calculation analysis both reveal it with hexagonal structure. Their physical properties and photovoltaic performance were both characterized. We demonstrate that Ag3BiBr6 films are capable of storing stably over 30 days in air. These results will inspire more research works on developing and applying Ag3BiBr6 beyond solar energy applications.

Boosting efficiency of planar heterojunction perovskite solar cells to 21.2% by a facile two-step deposition strategy

The wet lead (II) iodide (PbI2) film-based two-step spin-coating procedure is employed to prepare good-performed planar heterojunction (PHJ) solar cell by simply controlling the remaining content of dimethyl sulfoxide (DMSO) solvent in PbI2 film. It was found that such wet PbI2 film was beneficial to produce pinhole-free, smooth, and highly crystalline perovskite film since the remaining DMSO could retard the crystallization of PbI2. By modulating the content of residual DMSO, the best performed device has efficiency as high as 21.20% with negligible photocurrent hysteresis. The average conversion efficiency has reached 20.15%, 14.42% enhanced comparing to annealing method. Our technique is simple but effective, and we expect it could be widely used especially for devices fabricated on flexible substrates.

Zinc Doped Hydroxyapatite Thin Films Prepared by Sol–Gel Spin Coating Procedure

In this study, ZnHAp layers deposited on a Si substrate were obtained by a sol–gel spin-coating procedure. The ZnHAp solutions used to obtain the ZnHAp coatings were investigated by dynamic light scattering (DLS) analysis, ζ-potential, ultrasound measurements, and flame atomic absorption spectrometry (AAS). The average measured hydrodynamic diameter from the DLS analysis, ζ-potential, and ultrasound measurements were analyzed so as to characterize and estimate the stability of the ZnHAp nanoparticles. The AAS results confirmed the presence of zinc in the gels used in the preparation of the ZnHAp layers. The layers were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results revealed the diffraction peaks of the hexagonal hydroxyapatite in all of the investigated samples. The morphology of the ZnHAp coatings annealed at 500 °C (ZnHAp-500) and 700 °C (ZnHAp-700), which evidenced that no fissures or cracks formed on the surface of the coatings. The biocompatibility assays indicated that the ZnHAp coatings did not present any toxicity towards the HeLa cells. Furthermore, the study regarding the cytotoxicity of the ZnHAp layers against microorganisms emphasized that ZnHAp coatings exhibited an inhibitory effect towards S. aureus bacterial cells and also towards C. albicans fungal cells.