Fabrication Of Transparent Electrodes Research Articles

Controlled Fabrication of Composite Transparent Electrodes for Semitransparent Perovskite Solar Cells with above 84% Fill Factor

In the quest to develop efficient semitransparent perovskite solar cells (ST‐PSCs), the primary challenge lies in transparent electrode fabrication. n–i–p‐type ST‐PSCs often suffer from low fill factors (FF) and power conversion efficiency (PCE), attributed to the undesirable buffer layer/transparent conductive oxide combination of the transparent electrode. In this context, this study proposes an efficient composite transparent electrode (CTE) system comprising an ultrathin MoO3 buffer layer (5 nm) and low‐power sputtered indium zinc oxide (45 W–220 nm). The electrode demonstrates excellent compatibility with Spiro‐OMeTAD‐based devices, effectively addressing the low FF and PCE challenges of ST‐PSCs. Employing the new CTE, the best‐performing ST‐PSCs with the absorption edge at 1.57 eV achieve a remarkable PCE of 21.96% with an FF of up to 83.80%. More transparent ST‐PSCs with thickness‐modulated absorbers and average transmittance of 50.77% at 600–1200 nm wavelength result in a PCE of up to 20.91% with the highest known FF of 84.02%. This study presents a general and viable approach for fabricating efficient ST‐PSCs.

Beyond Flexibility: Transparent Silver Nanowire Electrodes on Patterned Surfaces for Reconfigurable Devices

Silver nanowire (AgNW) emerges as a next‐generation transparent electrode material, offering enhanced flexibility and ease of fabrication compared to traditional transparent electrode materials, such as metallic oxides. In the previous research, the uniform deposition of AgNWs on flat surfaces is demonstrated, exhibiting high conductivity, flexibility, and excellent transmittance. However, the evolution of nano‐electronics technology necessitates the fabrication of transparent electrodes on non‐flat surfaces, such as those found in zenithal bistable devices and reconfigurable Fresnel lenses. In this study, a method is proposed to deposit AgNW material on uneven surfaces using the Mylar‐bar‐coating method, with a polyvinyl chloride (PVC)‐based Fresnel lens serving as the target surface. Additionally, the impact of varying AgNW suspension concentrations on transmittance and sheet resistance is investigated. To further reduce sheet resistance, a layer of conductive polymer, poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), is deposited on the AgNWs. The measurements reveal that a 2 mg mL−1 sample exhibits a sheet resistance of 187.83 W W−1 with 87.4% transmittance at 550 nm. After the PEDOT:PSS process, the sheet resistance decreases to 122.84 W W−1 with 84.4% transmittance. In this research, a solution is offered for the uniform deposition of AgNWs on patterned surfaces, paving the way for the next generation of optical devices.

Electric field driven printing of repeatable random metal meshes for flexible transparent electrodes

Electrohydrodynamic jet printing technology is recognized as one of the most desirable solutions for direct printing of metal meshes. However, electrohydrodynamic jet printing technology makes it difficult to achieve reproducible printing of random metal meshes due to the low stability as well as controllability of the cone jets. Here, a simple and cost-effective printing technique for fabricating flexible transparent electrodes with controlled knot-free random metal meshes was proposed. The simple and green fabrication of transparent electrodes with different random metal meshes was achieved by precisely adjusting the printing process parameters. The sheet resistance variation of the manufactured FTEs with random metal mesh was less than 10 %, showing excellent reliability and stability and environmental adaptability, demonstrating better optoelectronic performance, after 1000 cycles of bending, 180 cycles of adhesion testing, and 72 h of damp heat testing. More importantly, the diffraction experiments show that the fabricated random metal meshes can reduce the negative effects of higher-order diffraction and eliminate the moiré fringe phenomenon. A flexible touch screen application demonstrated the practicality of manufactured FTEs with random metal mesh (area: 80 mm × 130 mm, sheet resistance: 16 Ω/sq, transmittance: 86 %). The proposed method offers a very promising strategy for the efficient and green integrated fabrication of random metal meshes.

Effect of Calcinations Temperature on ZnO:Co Nanostructured Thin Films Prepared By Sol – Gel Method.

Nanostructured ZnO thin films were developed on medical-glass substrates using a sol gel dip coating process and calcinated at various temperatures (350, 450, and 550 C°). The impact of Co doping and effect temperature calcination on the structural, optical and electrical properties of ZnO:Co nanostructured thin films were investigated using XRD, SEM, Hall effect, and UV-Visible spectra measurements. Both nanostructured films have hexagonal-wurtzite crystals composition according to XRD analysis with the average crystallite sizes of ZnO:Co nanostructured thin films are of (26.7-102.1) nm. The FESEM findings show that the undoped ZnO thin film has the smoothest and more regular surface compared to the doped ZnO films, indicating that both films with nanoscale ZnO particles. The average transmittance of all films is about 69–91 % in the visible range and the band gap energy decreased from 3.283 to 3.205 eV with increase of temperature calcination. The Hall impact indicates that all thin films are n-type and the electrical conductivity increase from (12.4-16.2) in the ZnO:Co thin films. This one of the outstanding property of ZnO thin films, both undoped and doped with cobalt, enables the fabrication of transparent electrodes for flat panel displays, metal-insulator-semiconductor diodes, and solar cells.

Sigmoidal Dependence of Electrical Conductivity of Thin PEDOT:PSS Films on Concentration of Linear Glycols as a Processing Additive.

We investigate the sigmoidal concentration dependence of electrical conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) processed with linear glycol-based additives such as ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), hexaethylene glycol (HEG), and ethylene glycol monomethyl ether (EGME). We observe that a sharp transition of conductivity occurs at the additive concentration of ~0.6 wt.%. EG, DEG, and TEG are effective in conductivity enhancement, showing the saturation conductivities of 271.8, 325.4, and 326.2 S/cm, respectively. Optical transmittance and photoelectron spectroscopic features are rather invariant when the glycols are used as an additive. Two different figures of merit, calculated from both sheet resistance and optical transmittance to describe the performance of the transparent electrodes, indicate that both DEG and TEG are two most effective additives among the series in fabrication of transparent electrodes based on PEDOT:PSS films with a thickness of ~50–60 nm.

Synthesis, transfer and application of graphene as a transparent conductive film: a review

Transparent conductive films (TCFs) have been widely used as transparent electrodes in nanoelectronic and energy storage devices. An ideal electrode should have high optical transparency, electrical conductivity and carrier mobility to increase the performance and efficiency of devices. Graphene is introduced as a promising new-generation material for the fabrication of transparent electrodes because of its unique electrical, optical and mechanical properties. Consistent efforts, such as the synthesis and transfer of graphene, have been exerted to produce excellent transparent electrodes. This article presents the methods that have been used to produce graphene, such as chemical vapour deposition, solution processing and chemical reduction. In addition, the benefits and drawbacks of several transfer techniques, such as chemical etching from a metal substrate, roll-to-roll process, spin coating, dip coating, drop casting and spray coating, are briefly discussed. For instance, the transfer of graphene for TCF preparation remains challenging. The potential applications of graphene-based TCFs, such as in flexible displays, solar cells, supercapacitors, transistors and electrochromic films, are also discussed.

A simple transparent electrode fabrication method by filling in Ag composites into scratch gap

In this work, we demonstrate a simple and cheap process for the fabrication of transparent electrodes. We scratched the surface of polydimethylsiloxane (PDMS) to create 0.5 mm-, 1 mm-, and 2.0 mm-deep gaps to form a crossed grid; we then filled the gaps with a Ag composite and analyzed the optical and thermoelectrical properties of the system by infrared spectroscopy, optical microscopy, and scanning electron microscopy. We then plotted the current-voltage curves derived from connecting the system to a battery and assessed the electrical properties, as well as the Joule heating derived from current transmission. We discovered that the Joule heating was more dependent on the current than the voltage of the skin; this knowledge was applied by employing our circuit on a wearable heating device, which demonstrated the ability to heat the skin underneath when stimulated with a 0.6 A current and 9 V. Finally, we also demonstrated the applicability of our PDMS-supported Ag circuit by connecting it to a battery, and employing the circuit to illuminate an LED light.

Correction: A toxicology-informed, safer by design approach for the fabrication of transparent electrodes based on silver nanowires

Correction for ‘A toxicology-informed, safer by design approach for the fabrication of transparent electrodes based on silver nanowires’ by Djadidi Toybou et al., Environ. Sci.: Nano, 2019, DOI: 10.1039/c8en00890f.

A toxicology-informed, safer by design approach for the fabrication of transparent electrodes based on silver nanowires

A safer by design approach is demonstrated for the synthesis and integration of silver nanowires into commercial devices.

Analysis of the electro-optical response of graphene oxide dispersions under alternating fields

Recently, graphene oxide (GO) has attracted much attention because of its many potential applications, such as the fabrication of transparent electrodes or drug delivery, in addition to its use as a precursor for large-scale production of graphene flakes. However, the interaction of this material with electric fields is yet poorly understood, and only recently the orientation of GO particles with an electric field was achieved. In this work, we analyse the electro-orientation of GO flakes in aqueous suspension in the absence of interparticle interactions, under different experimental conditions. From the measurement of linear dichroism, the electrical polarizability of the GO flakes as a function of the field frequency was calculated. The results show a pronounced relaxation process in the kHz range that leads to a large high-frequency polarizability. This phenomenology is explained as follows: For high-frequency fields, the polarizability is that of conducting particles immersed in a dielectric; for frequencies below the kHz range, in contrast, ions in solution redistribute and screen the induced dipole. Hence, the use of high-frequency electric fields strongly enhances GO electro-orientation. Furthermore, from the linear dichroism measurements, the particle absorption coefficient and the sample size distribution could be obtained.

Effect of annealing on the microstructural, optical and electrical properties of ZnO nanowires by hydrothermal synthesis for transparent electrode fabrication

ZnO nanowires were grown by hydrothermal synthesis and the effect of annealing on their physical properties was investigated by field-emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, spectrophotometry and Hall effect measurements. The nanowires adopted the c-axis [0 0 1] growth orientation of the underlying gallium and aluminium co-doped ZnO seed layer and their vertical alignment improved with annealing temperature up to 250 °C, above which it became random at 350 °C. This was attributed to the improvement in crystallinity up to 250 °C and its deterioration at 350 °C. Energy dispersive spectroscopy confirmed that the Zn:O atomic ratios for all samples were nearly stoichiometric. Average optical transmittances around 50–70% were observed in the visible region. The optimum electrical properties for transparent electrode fabrication were achieved at 250 °C, where the carrier concentration was maximum (5.5 × 1020 cm−3) and electrical resistivity was minimum (1.1 × 10−2 Ω cm).

Low temperature synthesis of ZnO nanowires on GAZO thin films annealed at different temperatures for solar cell application

ZnO nanowires were hydrothermally grown on sputtered gallium and aluminium co-doped ZnO (GAZO) thin films as seed layers and the effect of seed layer annealing temperature on their microstructural and optoelectronic properties was investigated. Atomic force microscopy revealed an increase in the GAZO films' mean particle size and surface roughness with annealing temperature. The GAZO films exhibited a zincite phase with a preferred orientation along the (002) plane and their crystallinity improved with annealing temperature, resulting in low electrical resistivity. The nanowires' alignment improved with seed layer annealing temperature up to 150°C and then deteriorated at 250−350°C. This was attributed to the improvement in nanowire crystallinity up to 150°C and its deterioration at 250–350°C. Energy dispersive spectroscopy confirmed that the nanowires were closer to stoichiometric ZnO (1:1). Raman spectroscopy revealed the presence of few defects and slight residual tensile stress in the nanowires, in corroboration with XRD analysis. The films and nanowires exhibited average visible transmittances around 75–85% and 50–80%, respectively. The least electrical resistivity (7.0×10−3Ωcm) and highest figure of merit (1.02×10−2Ω−1) were obtained for the well-aligned nanowires grown on 150°C annealed films, demonstrating their suitability for solar cell transparent electrode fabrication.

Hydrothermal synthesis of ZnO nanowires on rf sputtered Ga and Al co-doped ZnO thin films for solar cell application

We report the hydrothermal synthesis of ZnO nanowires on rf sputtered gallium and aluminium co-doped ZnO (GAZO) thin films as seed layers. Their morphological, structural, optical and electrical properties were systematically tuned by optimizing the growth temperature, time and solution concentration for application as transparent electrodes in solar cells. The GAZO seed layer had a mean particle size of 77.82 nm, root mean square surface roughness of 6.07 nm and predominant (002) grain orientation. Energy dispersive spectroscopy confirmed the presence of only Zn and O in the ZnO nanowires. Growth temperature and time had pronounced effects on the nanowires' axial growth rate while solution concentration affected their lateral growth. The nanowires adopted a (002) preferred growth orientation of the GAZO seed layer and their crystallinity improved with growth temperature, time and solution concentration. Average optical transmittances around 50–80% were observed in the visible region. Raman spectroscopy confirmed the presence of few defects and negligible residual stress in the nanowires. Well-aligned, hexagonal column shaped nanowires with low electrical resistivity (1.4×10−2Ωcm) and high figure of merit (8.3×10−3Ω−1) were obtained with optimized growth parameters (2 h, 90°C and 25 mM), demonstrating their suitability for transparent electrode fabrication.

Low temperature synthesis of radio frequency magnetron sputtered gallium and aluminium co-doped zinc oxide thin films for transparent electrode fabrication

Gallium and aluminium co-doped zinc oxide (GAZO) thin films were prepared on glass substrates at low temperatures by radio frequency (rf) magnetron sputtering and their physical properties were investigated. All films possessed a hexagonal wurtzite crystal structure with a strong growth orientation along the (002) c-axis. The (002) peak intensity and mean crystallite size increased with substrate temperature from room temperature (RT) to 75°C and then decreased at 100°C, indicating an improvement in crystallinity up to 75°C and its deterioration at 100°C. Scanning electron microscopy (SEM) micrographs revealed the strong dependency of surface morphology on substrate temperature and energy dispersive spectroscopy (EDS) confirmed the incorporation of Ga and Al into the ZnO films. All films exhibited excellent transmittances between 85 and 90% in the visible region and their optical band gap increased from 3.22eV to 3.28eV with substrate temperature. The Urbach energy decreased from 194meV to 168meV with increasing substrate temperature, indicating a decrease in structural disorders which was consistent with X-ray Diffraction (XRD) analysis. Films deposited at 75°C exhibited the lowest electrical resistivity (2.4Ωcm) and highest figure of merit (7.5×10−5Ω−1), proving their potential as candidates for transparent electrode fabrication.

Mussel-Inspired Polydopamine-Functionalized Graphene as a Conductive Adhesion Promoter and Protective Layer for Silver Nanowire Transparent Electrodes

For the scalable fabrication of transparent electrodes and optoelectronic devices, excellent adhesion between the conductive films and the substrates is essential. In this work, a novel mussel-inspired polydopamine-functionalized graphene/silver nanowire hybrid nanomaterial for transparent electrodes was fabricated in a facile manner. Graphene oxide (GO) was functionalized and reduced by polydopamine while remaining stable in water without precipitation. It is shown that the polydopamine-functionalized GO (PFGO) film adhered to the substrate much more easily and more uniformly than the GO film. The PFGO film had a sheet resistance of ∼3.46 × 10(8) Ω/sq and a transparency of 78.2%, with excellent thermal and chemical stability; these characteristics are appropriate for antistatic coatings. Further reduced PFGO (RPFGO) as a conductive adhesion promoter and protective layer for the Ag nanowire (AgNW) significantly enhanced the adhesion force between AgNW networks and the substrate. The RPFGO-AgNW electrode was found to have a sheet resistance of 63 Ω/sq and a transparency of 70.5%. Moreover, the long-term stability of the RPFGO-AgNW electrode was greatly enhanced via the effective protection of the AgNW by RPFGO. These solution-processed antistatic coatings and electrodes have tremendous potential in the applications of optoelectronic devices as a result of their low production cost and facile processing.

Effect of gallium doping on the structural, optical and electrical properties of zinc oxide thin films prepared by spray pyrolysis

Gallium-doped zinc oxide (GZO) thin films were deposited onto glass substrates by the spray pyrolysis technique and the effect of gallium (Ga) doping on their structural, optical and electrical properties was investigated by X-ray Diffraction (XRD), Spectrophotometry and Current–Voltage (I–V) measurements, respectively. XRD studies revealed that all films were polycrystalline in nature, with a hexagonal wurtzite crystal structure and a predominant (002) c-axis orientation. Ga doping resulted in deterioration of the film's crystallinity, increase in full width at half maximum (FWHM) and reduction in the mean crystallite sizes. All GZO thin films had relatively higher average transmittances, approximately 70–85% in the visible region as compared to the undoped ZnO thin films. Introduction of Ga led to a blue shift in the optical band gap from 3.26eV to 3.30eV and an increase in the Urbach energy from around 67meV to 100meV. Ga doping induced a decrease in sheet resistance leading to a minimum electrical resistivity of 1.2Ωcm and a maximum figure of merit of 1.02×10−4Ω−1 for the 1at% GZO thin film, indicating its suitability for optoelectronic applications, especially transparent electrode fabrication.

Study on the fabrication of transparent electrodes by using a thermal-roll imprinted Ag mesh and anATO thin film

Transparent conductive films have been widely studied because of their potential applications in optoelectronic devices such as paper displays, dye-sensitized solar cells (DSSCs), organic lighting-emitting diodes (OLEDs), organic solar cells and so on. In this paper, we report on a low-resistance, a high-transparents conductive film that can be applied as It a flexible device substrate. In order to the fabricate transparent conductive film, we used a high-resolution roll imprinting method. The following steps were performed: The design and manufacture of an electroforming stamp mold, the fabrication of high resolution roll imprinted on flexible film, and the manufacture of an Ag grid that was filled by using a doctor blade process with a nano-sized Ag paste. Then on patterned Its films, antimony tin oxide was coated with ATO sol solution by using bar the coating method. The fabricated ATO/Ag mesh electrode showed good flexibility, and It exhibited a high optical transmittance of 85.3% in the visible wavelength and a sheet resistance of 41 Ω/sq. Furthermore, the bending test for mechanical properties showed that the ATO/Ag thin film had good flexibility.

Silver nanowires with semiconducting ligands for low-temperature transparent conductors

Metal nanowire networks represent a promising candidate for the rapid fabrication of transparent electrodes with high transmission and low sheet-resistance values at very low deposition temperatures. A commonly encountered challenge in the formation of conductive nanowire electrodes is establishing high-quality electronic contact between nanowires to facilitate long-range current transport through the network. A new system involving nanowire ligand removal and replacement with a semiconducting sol-gel tin oxide matrix has enabled the fabrication of high-performance transparent electrodes at dramatically reduced temperatures with minimal need for post-deposition treatment.

Influence of Ambient Humidity on the Conductivity Enhancement of PEDOT:PSS Films during the Acetic Acid Treatment

In this work, well-controlled ambient humidity can adjust the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films during an acetic acid rinse. The conductivity of PEDOT:PSS films can be dramatically enhanced by optimizing post-treatment ambient humidity. The conductivity of PEDOT:PSS films increase from 0.33 S/cm for the pristine to 1090 S/cm at relative humidity (RH) of 60% while that of PEDOT:PSS films is only 5.04 S/cm at H2O < 1 ppm. The improvement conductivity should be attributed to enhanced phase segregation, removing of some PSS chains from PEDOT:PSS and reorganization of PEDOT chains at higher RH. This facile solvent-treated route provides a promising transparent electrode fabrication method to replace ITO electrode in organic photovoltaics (OPVs).

Low-voltage Sputtering Deposition of Transparent Conductive GAZO Thin Films for Minimizing Damage to Organic Layers

Organic electronics devices could have many advantages such as flexibility, simple process and low fabrication cost. Minimizing damage to organic layers during sputtering is important for the improvement of organic optoelectronic performance and lifetime. In order to achieve improved device performance, degradation of organic layers, which could be occurring during manufacturing, should be suppressed. Among the methods available for the fabrication of transparent electrodes, sputtering deposition possess many advantage over others, such as simple apparatus and procedure, high deposition rate, and wide deposition area. [1] Because of its unique structure, the use of a facing targets sputtering (FTS) system could effectively reduce damage during sputtering. [2] In this study, we prepared transparent, organic, GAZO thin films deposited onto Alq3 using an FTS system for the purpose of investigating the damage caused to organic layer by sputter deposition. To measure the damage sustained by organic materials during sputter deposition, we carried out depositions of transparent, conductive, gallium-aluminum doped Zinc Oxide (GAZO) thin films onto organic layers, using an FTS system.