Doctor Blade Method Research Articles

Improvement of Multilayer Applying Method for Catalyst Layer of PEFC Using Inkjet Coating Printer

It is expected that a popularization of Polymer Electrolyte Fuel Cell (PEFC) as clean energy contributes to the global warming prevention. However, its manufacturing cost is so high that the reduction in the production cost is an exigence for further spread. Because the cost of platinum catalyst in the catalyst layer of the membrane electrode assembly (MEA) accounts about 46% of the total manufacturing cost, the reduction of the usage of platinum is a shortcut of the cost reduction. Generally, because a catalyst layer (CL) of MEA is manufactured by a doctor blade method, this method has some problems such as a bad dispersibility of Pt catalyst in CL and a difficult thickness control. Therefore, our laboratory has proposed applying an inkjet coating printing to the CL manufacturing process to solve these problems. Because the CL applied by an inkjet coating printing is extremely thin, a multilayer applying is necessary to obtain enough thickness of CL. However, the previous study confirmed that the cell performance of CL composed of a multilayer was lower than that of single layer. In order to investigate the cause of the performance deterioration, we aimed to elucidate the influences of the ionomer additive rate and the CL structure on the cell performance, the correlation between ionomer and Pt catalyst. As a result, the reason for the performance deterioration originated to the obstruction of the electron transport because ionomer and platinum separated in the catalyst ink droplet in the drying process of the catalyst ink, and the ionomer becomes excessive in the supernatant. Because an electron and a proton does not reach to the reaction field that is the three phase interface by this separation, the cell performance was deteriorated by the increase of the resistance and activation polarizations. However, because these polarizations are minimized when the I/C ratio is 2/3, this I/C ratio is an optimum value for the ionomer and platinum to disperse uniformly. Therefore, the gradation CL was formed by increasing I/C ratio from the GDL side to the membrane side at each applying using this separation phenomenon. As a result, the performance of the cell with the gradation CL was enhanced compared with the conventional three layer as shown in Fig.1 because the proton moves smoothly by gradually decreasing ionomer from the membrane side to the GDL side, and oxygen also diffuses to the reaction field smoothly by not being obstructed to water in the catalyst layer.The effectiveness of the inkjet printing method was able to be confirmed because various structure of the CL such as the gradation type was able to be manufactured. However, because a platinum and an ionomer separates if I/C ratio increases, it is necessary to adjust I/C ratio to 2/3 if an appropriate three-phase field side is formed. Oppositely, it is possible to make the platinum percentage vary to the thickness direction of the CL using the separation phenomenon of ionomer and platinum. Figure 1

Fabrication of Freestanding Flexible Electrode Based on PEDOT:PSS Polymer Composite for Li – S Batteries

Currently, Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is considered a promising composite in energy conversion and storage devices due to its high electrical conductivity, chemical stability, outstanding flexibility and great electrochemical properties. Owing to its favorable mechanical and electrical properties PEDOT:PSS has wide applications in transparent electrodes, photovoltaics, fuel cells, supercapacitors and lithium-ion batteries [1-2]. Flexible free-standing sulfur @ MWCNT @ PEDOT:PSS composite films might be prepared using various techniques such as vacuum infiltration, facile solution mixing method, rod-coating technique, hydrothermal method, and doctor-blade technique [3]. In our review, we synthesized PEDOT:PSS @ sulfur@ MWCNT composite film by a doctor-blade technique onto the polypropylene (PP) substrate. First, the cathode composite was prepared by mixing multi-walled carbon nanotubes (MWCNT) composite with a sulfur content 1:1, PEDOT:PSS water-based dispersion and DMSO as a solvent to form a homogeneous slurry. The slurry was coated onto PP substrate by doctor-blade method and subsequently dried in a vacuum oven. Furthermore, sulfur @ MWCNT @ PEDOT:PSS film was structurally characterized by scanning electron microscopy (SEM) analysis. SEM images show the flexible film, which exhibits a network structure formed by interpenetration of MWCNTs and PEDOT:PSS. Sulfur nanoparticle clusters are surrounded by CNT networks, forming intimate interfaces with each other. According to EDS results, uniform distribution of each element can be observed. Acknowledgement This work was supported by the research projects АР08052143 “Development of Wearable Self-Charging Power Unit” from the Ministry of Education and Science of the Republic of Kazakhstan.

Architectural design of new conjugated systems carrying donor-π-acceptor groups (carbazole-CF3): Characterizations, optical, photophysical properties and DSSC's applications

In this study, two new organic dyes containing substituted N-octyl carbazole as electron donor and -CF3 units as electron acceptor group were designed and synthesized for ZnO-based dye sensitized solar cells (DSSCs). The synthesized carbazole derivatized compounds 3,6-bis(3,5-bis(trifluoromethyl)phenyl)-9-octyl-9H-carbazole (IVa) and 3,6-bis(4-(trifluoromethyl)phenyl)-9-octyl-9H-carbazole (IVb) were characterized by FT-IR, 1H NMR, 13C NMR, HMBC and CHN analyses. The spectroscopic (UV–Vis and FL) and thermal properties (TGA-DTA) of these compounds were also investigated. The produced (IVa and IVb) ZnO films were used as photoanodes in all DSSCs. Microwave-assisted hydrothermal method was used to synthesize ZnO nanopowders with different morphologies which are used as photoanodes in DSSCs. The structural and morphological properties of ZnO nanopowders were investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). ZnO-DSSCs were produced through coating ZnO nanopowders on transparent conductive fluorine-doped tin oxide (FTO) coated glass substrate using the Doctor Blade method. Current-voltage measurements of all produced DSSCs were carried out under a solar simulator with AM 1.5 G filter having an irradiance of 100 mW/cm2. Solar cell performances of all DSSCs such as; open-circuit voltage (Voc), short circuit current (Jsc), fill factor (FF) and power conversion efficiency (PCE) were analyzed.

IImproved performance of CdS powder-based hybrid solar cells through surface modification

The effects of surface modification of CdS through organic Eosin-Y, indoline D205, and Ru-based complex N719 and N3 dyes on CdS-based hybrid solar cells were studied. Chemical bath deposition (CBD) and doctor blade methods were in turn employed to fabricate the CdS specimens on Indium-Tin Oxide (ITO) covered glass substrates. P3HT material with and without dye coatings was covered through a spin-coater on the surface of CdS specimens. Ag paste was then deposited on the surface of P3HT to obtain hybrid solar cells. Structural analysis indicated that CdS powders showed a cubic growth with the preferred orientation of (111). Morphological analysis demonstrated that CdS powders exhibited hierarchical morphology and the morphology turned to granular structure with some porosity upon deposition of both N3 dye and P3HT layers. Absorption plots indicated that Eosin-Y dye loading led to a rise in the absorbance values of CdS specimens. After dye loading, photoluminescence data of CdS-based heterostructure illustrated a decrement in the luminescence intensity, implying that effective exciton dissociation was obtained. Current density-voltage (J-V) characteristics of the hybrid solar cells depicted that the best overall efficiency was observed for Eosin-Y-modified cell as 0.135%. This proved that surface modification by Eosin-Y dye led to a better interfacial contact between CdS and P3HT bilayer due to the enhancement in the charge separation.

Improvement of Multilayer Applying Method for Catalyst Layer of PEFC Using Inkjet Coating Printer

Polymer Electrolyte Fuel Cells are expected to be widly used as clean energy source. Generally, because a catalyst layer of the membrane electrode assembly in PEFC is manufactured by a doctor blade method, it has problems such as a bad dispersibility of Pt catalyst and a difficult thickness control in precisely. Our laboratory proposes applying an inkjet coating printing to the CL manufacturing process to solve these problems. Because the CL applied by an inkjet coating printing is extremely thin, a multilayer applying is necessary to obtain enough thickness. However, the cell performance of CL composed of a multilayer was lower than that of single layer. The reason was to have obstructed the electron transport property by separating ionomer and Pt in the catalyst ink. The cell performance has been enhanced by the formation of the CL where I/C ratio was changed from GDL to the direction of the membrane.

Development and investigation of the flexible hydrogen sensor based on ZnO-decorated Sb2O3 nanobelts

Hydrogen is regarded as the next-gen fuel for vehicles to avoid the emission of toxic gases, which needs a continuous monitoring of the concentration level. In the design of the H2 sensor, especially of flexible type, a sensing layer will be blended, which affects the sensing performance of the device. Based on this concern, the present investigation is carried out to understand the effect of the bending angle toward the sensing performance of bare and ZnO (n-type)-decorated Sb2O3 (p-type) nanobelt–based sensors for hydrogen gas. The sensing element was prepared by the thermal chemical vapor deposition followed by the drop-casting method. Furthermore, the role of the zinc precursor (molar concentration—1 M–3 M) on the preparation of ZnO-decorated Sb2O3 nanobelts was studied. Various techniques were used to confirm the formation of ZnO-decorated nanobelts such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), and Fourier transform infrared spectroscopy (FTIR). From these analyses, 1 M concentration of the zinc precursor shows uniform distribution of nanoparticles over the surface of Sb2O3 nanobelts. However, agglomeration was observed when the concentration of the zinc precursor increases from 1 M to 3 M. Later, the prepared nanobelts were deposited on the OverHead Projector (OHP) sheet by the doctor blade method for sensing hydrogen gas at 100 °C at a concentration of 1000–3000 ppm. In addition to it, the effect of the substrate bending angle (0°, 45°, 60°, and 90°) was analyzed at a fixed concentration of H2 gas (1000 ppm). From this study, it is clear that the highest sensing response was achieved for 1 M decorated nanobelts compared with bare as well as other concentrations because of uniform distribution of nanoparticles on the surface of nanobelts. Moreover, the prepared sample demonstrates better sensing performance with the bending of substrates, which suggests that the prepared sensor could be used for flexible electronic devices. The prepared nanobelts show a good H2 gas–sensing response even with bending of the substrates. The work suggests that the prepared sensor is applicable for flexible electronic devices.

Insights into the performance and degradation of polybenzimidazole/muscovite composite membranes in high–temperature proton exchange membrane fuel cells

To improve the performance and durability of phosphoric acid (PA) doped polybenzimidazole (PBI) membranes in high–temperature proton exchange membrane fuel cells (HT–PEMFCs), in this work, as–received natural muscovite (Mus), a clay material, was successfully incorporated into PBI matrix as an inorganic filler through the doctor blade method. The amount of Mus was varied (0.5–2 wt%) to explore its impact on the proton conductivity, mechanical and dimensional stability, power density, durability, and acid retention ability of the composite membranes. As the incorporation of Mus into membranes can introduce interactions with polymer chains and PA molecules to afford additional proton transport pathways at the interfaces in Mus–PBI and Mus–PA crosslinks, the membrane with 1 wt% Mus showed highest power density of 586 mW cm−2 at 150 °C without humidification, 24% higher than the pure PBI membrane (474 mW cm−2). Meanwhile, the PA doped composite membrane with 1 wt% Mus also displayed the highest mechanical strength (7.5 MPa) and lowest dimensional swelling (70.99% in area swelling and 202% in volume swelling). Compared with the pristine PBI membrane, the composite membranes had significantly improved durability under accelerated stress test (AST). The decreased ohmic resistance and increased polarization resistance after AST are related to the membrane thinning and the loss of catalyst active area, respectively. Most importantly, it was found that the strong interactions between Mus and PA molecules lead to improved acid retention ability of the composite membranes, thus less leached acid from the composite membrane reduces the negative effects on the catalyst degradation to alleviate degradation on cell performance and durability.

Effect of alkali metal nitrate treatment on the optical properties of CsPbBr3 nanocrystal films

Colloidal cesium lead bromide (CsPbBr3) perovskite nanocrystals (NCs) are fabricated as densely packed thin films using doctor blade method through a layer-by-layer assembly approach. It is found that the optical properties of the CsPbBr3 NC films are significantly improved after a ligand exchange of oleic acid (OA) and oleylamine (OAm) by sodium and potassium nitrate in ethyl acetate. Ligand-induced surface defects are passivated by the sodium and potassium cations and nitrate, which leads to the improvement in photoluminescence (PL) and life-time properties. Compared with pristine OAm-OA capped CsPbBr3 NC film, Alkali-metal nitrate salts treated films are showing higher PL intensity and longer carrier-lifetime, evidencing their potential use to achieve defect-free inorganic perovskite NC films.

Preparation by Hydrothermal Method of TiO2-RGO Nanocomposite and Using as Photoanode of Dye-Sensitized Solar Cell

We explored the photoanode properties of DSSCs by used RGO and TiO2 nanoparticles as an optical electrode (we used the doctor's blade method). Using the hydrothermal process, we prepared a nanocomposite of TiO2/RGO. SEM and XRD, tests were used to study the structural properties of TiO2 and TiO2/RGO. When compared the J-V properties of the integrated devices made to those made, the J-V properties of the integrated devices came out on top of used TiO2/RGO as the photoanode in a solar cell for TiO2/RGO, which increased the PCE (8.674±0.063%). We were able to improve the short circuit current density (Jsc) and the power conversion efficiency (PCE) for the effective region by adding RGO to the TiO2. The PCE has improved due to better electron transport, improved electron collection in photoanode, and increased light-harvesting performance. As a result, RGO with distinct structural and optical properties is a viable choice in DSSC.

Effect of dye absorption time on performance of ZnO, TiO2 and ‎SnO2 nanoparticle photo-anodes in dye sensitized solar cell

Interior design, engineering, and the configuration of materials used in photo‏-‏anode systems play ‎key roles in the photovoltaic performance of dye solar cells.‎‏ ‏In this study, the photo-anodes of dye sensitized ‎solar cells were fabricated based on TiO2, ZnO and SnO2 nanoparticles separately using doctor Blade method ‎on the transparent conductive oxide as substrates, then sensitized with N719 dye. Due to the fact that the dye ‎plays the role of photon absorption, different photo‏-‏anode oxides were placed in a N719 dye solution over a ‎different time period.‎‏ ‏Based on current-voltage curve, efficiency parameter, short-circuit current density, ‎open circuit voltage, and fill factor of the cells were obtained. The results of current-voltage characterization ‎indicate that the best time for the N719 dye loading for the TiO2 and SnO2 layers is 20 h and for the ZnO layer ‎is 1 h.‎‎

Green Synthesis of Zinc Oxide Nanoparticles Using Ixora Coccinea Leaf Extract for Ethanol Vapour Sensing

This article reports the effects of natural plant proteins on the morphology of zinc oxide nanoparticles (ZnONPs) prepared via a precipitation method. Green synthesised ZnONPs have a wide range of uses such as biomedical applications, water purification, optical devices and gas sensors. The non-toxic and economical technique described in this article is favourable for large-scale production too. ZnONPs were produced from a zinc acetate precursor with dye extract of Ixora Coccinea (IC) leaves as a capping agent. The as-prepared ZnONPs were characterised by X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible (UV-vis), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. The XRD analysis showed an average crystallite size of 23 nm. The SEM analysis revealed a reduction in aggregation of ZnO crystallites due to addition of dye extracts of IC. EDX and UV-vis results confirmed the formation of pure ZnONPs. Finally, the gas sensing properties of ZnO films, prepared by doctor blade method, were used to detect ethanol vapour. The results showed gas response ratios of 28.7 and 5.4 at 800 ppm and 40 ppm exposure, respectively. Furthermore, the response time and recovery time were found to be 24 sec and 47 sec, respectively at 200 ppm exposure of ethanol vapour.

Pengaruh Agen Pengikat Silang dan Waktu Polimerisasi Poli Asam Tanat pada Efisiensi Dye Sensitized Solar Cell (DSSC)

Abstract— Dye sensitized solar cell (DSSC) is a device that can convert light energy into electrical energy. Research on the DSSC continues to look for DSSCs with high efficiency values. The efficiency of DSSC is influenced by many things, one of which is the ability of the dye to absorb light energy. The dye used in this research is poly tannic acid obtained from the polymerization process of tannic acid. This polymerization is carried out to improve the ability of the dye to absorb sunlight. TiO2 / Cu paste was made using the sol gel method and coated on ITO glass using the doctor blade method. The formed layer is immersed in dye while the counter electrode is made with a candle flame. The DSSC was assembled to form a sandwich structure and electrolyte was dropped on the two electrodes. DSSC measured the voltage generated with a multimeter. The results of the UV-Vis analysis on the polymerized dye showed a bathochromic shift and an increase in the absorbance value. The results of FTIR analysis on polymerized dyes appeared ether groups in the range 1050–1250cm- 1 . The presence of this ether group indicates the formation of tannic acid poly. The highest DSSC efficiency found with the polymerized dye was 7.69% with polymerization time of 14 hours and the volume of crosslinking agent (TMPGDE) 115µL. Keywords: DSSC, Polymerization, Tannic Acid, Poly Tannic Acid, Efficiency

Defects rich nanostructured black zinc oxide formed by nanosecond pulsed laser irradiation in liquid

Zinc oxide (ZnO) is a wide bandgap semiconductor for energy applications while the spectral absorption only in UV region limits the use as a visible light absorber. Here, visible light absorbing modified ZnO (black) is prepared by creating surface defects and vacancies using pulsed laser irradiation in liquid. The modified ZnO nanoparticles have spherical morphology and they are free from impurity phases. The optical bandgap of this modified material is narrowed by increased irradiation time with a morphological transformation to mostly nanospheres. XPS analysis confirmed the oxygen vacancies contribution and the valance band study showed a reduction in the band edge. With the results of Raman and photoluminescence spectra, the oxygen defects and vacancies were confirmed. Thin films were fabricated using these materials via doctor blade method and their photocatalytic studies showed enhanced activity in organic dye decay under visible light. Results of this study show a facile method for fabrication of defects rich metal oxide nanomaterials by pulsed laser irradiation in liquid.

Ag nanoparticle-decorated SiO2@TiO2 hierarchical microspheres improve the efficiency of dye-sensitized solar cells

SiO2@TiO2-Ag (STA) microspheres decorated with Ag nanoparticles (Ag NPs) were prepared and assembled into the photoanode. The photoanode composed of STA microspheres and TiO2 nanoparticles (P25) was prepared by doctor blade method. UV–vis measurement indicates that the introduction of a few STA microspheres observably enhances the light scattering and capturing ability of the photoanode. The photoelectric conversion efficiency of the DSSCs with 2wt% STA photoanode increased to 7.4% from 4.3% comparing with pure P25 TiO2 nanoparticles. The configuration DSSCs have the maximum short circuit current density (Jsc) of 16.0 mA cm−2 and open-circuit voltage (Voc) of 0.780 V, which are significantly higher than the pure TiO2 DSSCs. The significant improvement of the DSSCs performance can be due to the synergistic effect of the superior light scattering of STA and the localized surface plasma resonance (LSPR) effect of Ag NPs modified on the microspheres surface.

Energy transfer mechanism of KAlF4:Dy3+, Eu3+ co-activated down-conversion phosphor as spectral converters: An approach towards improving photovoltaic efficiency by downshifting layer

Rare earth activated fluoride phosphors have attention in recent years in the field of solid state lighting and solar cell efficiency enhancement. In the present study, RE (RE = Dy3+, Eu3+) activated/co-activated KAlF4 phosphor has been synthesized by low temperature wet chemical method. The structural feature of the samples was analyzed by X-ray Diffraction (XRD), which showed that the samples were crystallized in a well known structure. Photoluminescence (PL) measurement of KAlF4:Dy3+ phosphors we find that they can be efficiently excited at 351 nm and possess dominant emission bands centered at 482 nm (blue) and 572 nm (yellow). From Photoluminescence (PL) measurement of KAlF4:Eu3+ phosphors a strong orange emission at the peak wavelength of 594 nm and 616 nm were observed which could be attributed to the 5D0 → 7F1 and 5D0 → 7F2 transition in Eu3+ ions. On co-doping of rare earths in the host lattice, a strong blue and yellow emissions were observed together with the red emission. This co-doped phosphor is the coated on Si-solar cell by doctor blade method. Solar cell efficiency has been checked by I-V characteristics of the coated and blank cell. Theoretical quantum efficiency has been determined by Judd–Ofelt parameters for the proposed phosphor.

Influence of Different Solvents and High-Electric-Field Cycling on Morphology and Ferroelectric Behavior of Poly(Vinylidene Fluoride-Hexafluoropropylene) Films.

P(VdF-HFP) films are fabricated via a solution casting doctor blade method using high (HVS) and low (LVS) volatile solvents, respectively. The structural properties and the ferroelectric behavior are investigated. The surface structure and crystal phase composition are found to be strongly dependent on the type of solvent. LVS leads to a rougher copolymer surface structure with large spherulites and a lower crystallinity in contrast with HVS. The crystalline phase of copolymer films fabricated with HVS consists almost exclusively of α-phase domains, whereas films from LVS solution show a large proportion of γ-phase domains, as concluded from Raman and X-ray diffraction spectra. Virgin films show no ferroelectric (FE) switching polarization at electric field amplitudes below 180 MV/m, independent of the solvent type, observed in bipolar dielectric displacement—electric field measurements. After applying electric fields of above 180 MV/m, a FE behavior emerges, which is significantly stronger for LVS films. In a repeated measurement, FE polarization switching already occurs at lower fields. A shielding effect may be related to this observation. Additionally, Raman bands of polar γ-phase increase by high-electric-field cycling for the LVS sample. The solvent used and the resulting crystal phase composition of the virgin sample is crucial for the copolymer behavior during bipolar electrical cycling.

Facile synthesis of TiO 2 and Sn‐TiO 2 heterostructures based photoanodes for dye sensitized solar cells

In the present study, nanorods of TiO2, Sn-doped TiO2 (Sn-TiO2), TiO2@Sn-TiO2 and Sn-TiO2@TiO2 were prepared by sol-gel method. Dye-sensitized solar cells (DSSCs) photoanodes were synthesized by depositing films on fluorine doped tin oxide (FTO) glass substrate using doctor blade method. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and UV-Vis spectroscopy. XRD results indicated the formation of tetragonal anatase structure of TiO2 in pristine TiO2 and Sn-TiO2 films. It was observed that formation of heterostructure particles spured the conversion of TiO2 from anatase to rutile phase. SEM analysis indicated the formation heterostructures of rod like morphology with increased diameter. Optical parameters of films (absorbance, transmittance, refractive index, dielectric constants and band gap) were measured using UV-Vis spectroscopy data. The results confirmed that Sn doping decrease the bandgap. Amongst the four prepared films, band gap of Sn-TiO2@TiO2 heterosturcture based film was smallest (3.09 eV). The efficiency of Sn-TiO2@TiO2 heterostructure based DSSC was found to be 54.3% better compared with DSSC based on Sn-TiO2 and 96.37% better compared with the DSSC based on pristine TiO2.

In Situ Fabrication of Mn‐Doped 2D Perovskite‐Polymer Phosphor Films with Green‐Red Dual Emissions for Yellow Lighting

Abstract2D metal halide perovskites have emerged as highly bright and stable light emitters, which can be employed as phosphors for optically pumped luminescence devices. However, the intrinsic volatile property is the main weakness to achieve their long‐term lighting applications. Here, an in situ doctor blade method is developed to fabricate a flexible large‐area (20 × 25 cm2) PEA2PbI4:2Mn‐PVDF film with green‐red dual emissions. Under UV light‐emitting diode (LED) excitation, this yellow phosphor device shows a maximum luminance value of 250 cd m−2, an extremely large full width at half maximum of 189 nm, and a color coordinate of (0.47, 0.50). The device can pass 120 h of water soaking and 85 °C/85% relative humidity of harsh environment tests, which benefit from the strong interaction of 2D perovskite and hydrophobic PVDF polymer. Different from electroluminescence yellow LED devices, Mn‐doped 2D perovskite‐polymer phosphor films excited by UV LED and fluorescent lamp provide an opportunity to achieve low‐cost indoor yellow lighting in some UV‐sensitive places.

Dielectric Properties of BN-ZnO-GNP Doped PU-EG Composites

In this study, ZnO and GNP were added separately and together to improve the dielectric constant values of hexagonal boron nitride. Polyurethane and glycerol were used as binders. The productions were carried out by dispersing each additive separately in acetone and then coating it with the doctor blade method on aluminium foil. The characterizations were carried out with FTIR and SEM. Then, the capacitance values of each composite were first measured with the LCR meter and then the dielectric constant were calculated. According to the results, the highest dielectric constant values were obtained at the 100 and 120 Hz frequencies. At the frequency value of 100 kHz, the lowest dielectric constant was obtained in all composites. Compared to pure BN, an increase of 115% was achieved with ZnO contribution, while an increase of up to 145% was achieved with GNP contribution. The highest increase was achieved up to 160% with ZnO + GNP contribution. In addition, with the contribution of ZnO + GNP, the amount of decrease at high frequencies was less than the others. This is thought to be due to the combined effect of both ZnO and GNP, which has a large surface area.

Scalable fabrication of graphitic-carbon nitride thin film for optoelectronic application

Graphitic-carbon nitride has displayed a splendid future in cutting–edge optoelectronic gadgets, because of exceptional and promising physicochemical properties. In the course of recent years, lot of examination witnessed tremendous advancement in graphitic-carbon nitride as photocatalyst. In this work, graphitic-carbon nitride thin film was fabricated using cost-effective doctor-blade method. The structural, optical and electrical properties of the graphitic-carbon nitride thin film are investigated. Structural and morphological characterization result affirms the development of graphitic-carbon nitride thin film. Optical properties of graphitic-carbon nitride thin film are done by UV–Visible spectroscopy and photoluminescence measurements. The wide absorbance range, reduction in bandgap (1.88 eV) and the presence of luminescence center obviously indicate the future of graphitic-carbon nitride thin film in the optoelectronic application. Hall Effect measurement result reveals n-type conductivity and shows the carrier concentration value of −1.42X 1018 cm−3.