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Silver (Ag) grid transparent conducting films (TCFs) were firstly fabricated by selective laser ablation of Ag thin films prepared by radio frequency magnetron sputtering under the conventional scanning method (i.e., line-typed cyclic scanning, LTCS). The effects of grid parameters (i.e., Ag grid height, pitch, and line-width) on TCF morphology, optical transmittance, electrical conductivity, and comprehensive performance were studied. The optimal Ag grid height, pitch, and line-width were determined to be 800 nm, 1.0 mm, and 90 μm, respectively, and the resulting TCF showed a figure of merit of 11.38 × 10–2 Ω–1. Subsequently, two new scanning methods, i.e., frame-typed serial scanning (FTSS) and frame-line combined scanning (FLCS), were adopted to further optimize the fabrication process, and thus the TCF comprehensive performance. The results showed that as compared to the LTCS method, the FTSS and FLCS methods could effectively eliminate semicircular-shaped Ag grid line edges, and thus obtain relatively smooth and flat ones without obvious Ag material residues. The Ag grid TCF fabricated by using the FLCS method had the highest figure of merit of 13.02 × 10–2 Ω–1, indicating a further improvement in comprehensive performance. [ABSTRACT FROM AUTHOR]

Preparation and property optimization of silver (Ag)-embedded fluorine-doped tin oxide (FTO) films were achieved based on laser etching, sputtering Ag layers, furnace annealing, sputtering aluminum-doped zinc oxide (AZO) layers and laser annealing. Specifically, a nanosecond pulsed laser (λ = 532 nm) was used to etch grooves on FTO films before sputtering 5-nm-thick Ag layers, with an aim for enabling the Ag nanoparticles from the furnace-annealed Ag layers to be intensively embedded in the grooves under the thermal-induced dewetting effect. The optimal laser fluence for laser etching and temperature for furnace annealing were found to be 0.4 J/cm2 and 300 °C, respectively. The as-obtained Ag-embedded FTO film exhibited significantly improved optical and electrical properties, being attributed mainly to the decreased coverage area of the Ag nanoparticles on the FTO film surface and the furnace annealing effect. The subsequently sputtered 10-nm-thick AZO layer suppressed the internal light reflection from the Ag nanoparticles, and laser annealing further facilitated grain growth in the film. Therefore, the resulting film had the best comprehensive property with the highest figure of merit of 20.94 × 10–3 Ω–1, which was much higher than that of the original FTO film (7.65 × 10–3 Ω–1). This work may provide a new combined processing method for high-performance transparent conductive films. [ABSTRACT FROM AUTHOR]

A laser etching method was performed to achieve the dual purpose of fabricating grating structures and laser annealing on aluminum-doped zinc oxide (AZO) thin films, and thus improve the film photoelectric performances. Different line spacings and laser fluences were adopted to systematically explore the optimal laser etching condition. Too narrow line spacings or too high laser fluences led to light reflections at the grating external surface to cause more light dissipation, and too wide line spacings or too low laser fluences resulted in relatively small total grating lateral areas being detrimental to multiple internal light reflections. Moreover, too narrow line spacings brought about laser-caused lattice disorder and too high laser fluences produced laser-ablated spots or overburned traces. Therefore, using the medium line spacing and laser fluence, e.g. 40 μm and 0.6 J/cm2 in the present work, was more suitable for synchronously realizing grating structure fabrication and laser annealing. The corresponding AZO film exhibited the maximum figure of merit of 2.89 × 10−2 Ω−1, which was 1.6 times that of the untreated AZO film. This study is expected to expand performance improvement methods of TCO films and promote the application of laser-etched grating structures. [ABSTRACT FROM AUTHOR]

Silver (Ag) films were deposited on glass substrates by radio frequency (RF) magnetron sputtering and then ablated by a 532 nm nanosecond pulsed laser. The effects of laser fluence and defocusing amount on the width and depth of laser-ablated grooves on 100- and 600-nm-thick Ag films were systematically investigated under single- and multi-scan ablation. The results suggested that the Ag films could be successfully removed from the substrate owing to laser-induced thermoelastic force or vaporization. It was confirmed that laser fluence and defocusing amount played very important roles in controlling the width and depth of the laser-ablated grooves. In the present work, grooves with widths ranging from 53 to 196 μm and depths ranging from 56 to 196 nm were obtained on 100-nm-thick Ag films by single-scan laser ablation, and laser ablation or removal with controllable depths was realized on 600-nm-thick Ag films by adopting single- or multi-scan (i.e., scanning numbers of 1–6). Furthermore, square spiral Ag patterns were successfully obtained by single- and multi-scan laser ablation and showed good electrical conductivity in a simple circuit. This work may have great potential applications in various fields that demand width and depth control of laser ablation/removal. [ABSTRACT FROM AUTHOR]

A ZnO nanorod-coated FTO film was prepared by sputtering an AZO layer on FTO glass, thermal annealing of the AZO/FTO film, and hydrothermal growth of ZnO nanorods at 70 °C on the annealed AZO/FTO film using zinc foils as zinc source. Two other ZnO nanorod-coated FTO films were also prepared by hydrothermal growths of ZnO nanorods on the FTO glass and the unannealed AZO/FTO film respectively for comparison purpose. The results were observed in detail using X-ray diffraction, scanning electron microscopy, water contact/sliding angle measurement, spectrophotometry and four-point probe measurement. The ZnO nanorods on the annealed AZO/FTO film were found to exhibit denser distribution and better orientation than those on the FTO glass and the unannealed AZO/FTO film. As a result, the ZnO nanorod-coated annealed AZO/FTO film demonstrated superhydrophobicity, high transparency and low reflectance in the visible range. Also this film had the lowest sheet resistance of 4.0 Ω/sq, implying its good electrical conductivity. This investigation provides a valuable reference for developing multifunctional transparent conductive films. [ABSTRACT FROM AUTHOR]

The photoelectric properties of nickel (Ni)/fluorine-doped tin oxide (FTO) bilayer films were optimized by magnetic-field-assisted laser annealing using a 532 nm nanosecond pulsed laser. Laser annealing without a magnetic field was also performed for comparison purpose. Magnetic-field-assisted laser annealing can greatly promote grain growth and increase grain size in the films, thereby effectively enhance transmittance and reduce sheet resistance. Interestingly, after being laser annealed in a vertical magnetic field, the film surface was covered with sparsely distributed and agglomerated grains, resulting in relative low conductivity. In contrast, the surface of the film which was laser annealed in a transverse magnetic field exhibited densely and uniformly distributed grains, and thus had the highest transmittance and lowest sheet resistance. This work may provide a new idea for performance optimization of metal/FTO bilayer films. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ti layers were deposited by DC magnetron sputtering on commercial FTO glasses. [•] TiO2/FTO films were obtained by simultaneous oxidation and annealing of Ti layers. [•] The optimal TiO2/FTO film was formed at 400°C and with an oxygen flow of 15sccm. [•] The TiO2/FTO film was further optimized through coating sputtered AZO layer. [•] This work provides a reference for improving photoelectric property of TCO films. [ABSTRACT FROM AUTHOR]

The wetting behaviors of zinc oxide (ZnO) thin films, which were grown on aluminum-doped zinc oxide (AZO) and tin-doped indium oxide (ITO) buffer layers by hydrothermal process, are reported. The ZnO film grown on the AZO layer, which has a morphology containing micro- and nanoscaled features, shows a slight decrease in water contact angle (WCA) after UV illumination. The ZnO film grown on the ITO layer, which is composed of single-scale microrods, exhibits a transition between hydrophobicity and superhydrophilicity under UV exposure for 8h and dark storage for 2 weeks. The wettabilities of the both films are enabled to convert reversibly by alternative heating at 400°C and 100°C. This work may be of huge importance from the viewpoint of self-cleaning and anti-fogging applications based on wettability control of ZnO films. [ABSTRACT FROM AUTHOR]

Nanosecond pulsed laser etching for fabricating anti-reflective gratings and inducing synchronous laser annealing was performed on Ag/AZO films. The optimum grating pitch was determined by performance analyses of laser-etched unidirectional gratings, based on which laser-etched bidirectional gratings were fabricated to further determine the optimum grating tilt angle. The results revealed that with the increase of grating pitch, the grating ridge total-side-area was gradually decreased to cause a gradually weakened anti-reflective effect, but the superimposed heat-affected zones between adjacent grooves became smaller or even disappeared, which brought about different synchronous laser annealing effects. The unidirectional grating-textured film with a medium grating pitch of 200 μm showed the best overall performance under the combined influence from anti-reflective gratings and synchronous laser annealing. For the bidirectional gratings, although increasing the grating tilt angle did not change the grating ridge total-side-area, it would enable the laser energy to be more uniformly distributed on the whole film surface, producing a better synchronous laser annealing effect. The bidirectional grating-textured film with a grating tilt angle of 90° had the best overall performance with the highest FOM value of 2.18 × 10−2 Ω−1 that was ∼3.2 times that of the as-prepared film. The results are instructive for preparing high-performance TCO-based films. [ABSTRACT FROM AUTHOR]

Silver (Ag)/fluorine-doped tin oxide (FTO) bilayer films were prepared by sputtering Ag layers on commercial FTO glass. The effects of traditional furnace annealing, nanosecond pulsed laser annealing and furnace/laser dual annealing on the structure and photoelectric properties of the Ag/FTO films were investigated. It is found that all the annealing methods increased the grain size of the films, leading to enhancement of the transmittance and conductivity. Traditional furnace annealing at 400°C for 20min brought about the formation of smaller Ag nanograins, while subsequent 532nm nanosecond pulsed laser annealing with a fluence of 0.9J/cm2 melted the Ag nanograins to conglomerate with larger SnO2 grains, resulting in the highest figure of merit of 1.7×10−2 Ω−1. The results indicate that furnace/laser dual annealing is a more effective method for improving overall photoelectric properties of FTO-based films. [ABSTRACT FROM AUTHOR]

This study focused on utilizing a boron nitride (BN) layer to improve the photoelectric property stability of the flexible Al/Cu/ZnO multilayer thin film, which was prepared on a polyethylene terephthalate (PET) substrate by radio frequency (RF) magnetron sputtering. By analyzing surface morphology, chemical composition and photoelectric properties of flexible BN/Al/Cu/ZnO multilayer films with different BN layer thicknesses, the BN/Al/Cu/ZnO film with a 100-nm-thick BN layer (BN 100 /Al/Cu/ZnO), which had the best comprehensive photoelectric property with a figure of merit of 0.82 × 10−3 Ω−1, was chosen to further study the performance stability with storage temperature and time. It was found that as compared to the Al/Cu/ZnO film, the BN 100 /Al/Cu/ZnO film had more stable photoelectric properties at different storage temperatures and times, which was inferred to be attributed to the excellent heat and oxidation resistances of the BN layer that were conducive to avoiding surface damage and oxidation of the film. The results in this work demonstrate the key role of the BN layer in enhancing photoelectric property stability of the flexible Al/Cu/ZnO film, and may provide a feasible strategy for improving thermal and long-time stability of single-layer or multilayer flexible transparent conductive films. [ABSTRACT FROM AUTHOR]

Abstract An ultrasonic-vibration-assisted laser annealing method was developed to enhance the performance of fluorine-doped tin oxide (FTO) thin films. The influences of ultrasonic vibration, laser scan line overlapping rate (L OR) and laser spot overlapping rate (S OR) on surface morphology, FTO layer thickness, RMS roughness, crystal structure and photoelectric properties of the FTO films were investigated. The results indicated that the presence of ultrasonic vibration during laser annealing could significantly enhance the film compactness, and using moderate L OR and S OR values resulted in significantly decreased FTO layer thicknesses and RMS roughnesses as well as slightly increased crystallite sizes, thus yielding significantly improved optical transmittance values and slightly enhanced electrical conductivity values. It was found that the optimal L OR and S OR values for ultrasonic-vibration-assisted laser annealing of the FTO films were 80% and 90%, respectively. The as-obtained film possessed the best overall photoelectric property with an average transmittance (400–800 nm) of 85.9%, a sheet resistance of 8.7 Ω/sq and a figure of merit of 2.51 × 10–2 Ω–1. This work may be of great significance in terms of performance optimization of transparent conducting oxide (TCO) thin films. [ABSTRACT FROM AUTHOR]

• Ag/FTO films were subjected to ultrasonic-vibration-assisted laser irradiation. • Laser inducing grating structure and laser annealing were simultaneously achieved. • Ultrasonic vibration could enable the film surface to be at the optimal position. • Ultrasonic vibration could ensure uniformity and continuity of the grating structure. • The grating-structured Ag/FTO films exhibited excellent photoelectric properties. This work focuses on the fabrication of antireflection grating structures on Ag/F-doped SnO 2 (FTO) films by ultrasonic-vibration-assisted laser irradiation to compensate the optical transmittance loss due to coating the Ag layers. The effects of laser fluence and ultrasonic vibration on formation of laser-induced grating structures are investigated. The results indicate that ultrasonic-vibration-assisted laser irradiation can not only contribute to generating a complete and uniform periodic grating structure, it can also bring about a laser annealing effect to the film. Ultrasonic vibration is considered to play an important role in generating the grating structure by changing the defocusing amount of the film surface, inputting energy and providing mechanical vibration. Moreover, under the favorable influence of ultrasonic vibration, the laser parameter values can be lowered, and the interference of the laser-excited surface plasmons (SPs) with the incident laser can be facilitated. In this present work, the optimal grating-structured Ag/FTO film has the highest figure of merit of 3.26 × 10−2 Ω−1, showing significant increases compared to the untreated FTO (1.13 × 10−2 Ω−1) and the ultrasonic-vibration-free laser-irradiated Ag/FTO (2.34 × 10−2 Ω−1) films. This work may be of important enlightening and reference significance for preparing high-performance transparent conductive films. [ABSTRACT FROM AUTHOR]

To further improve electrical performance of FTO single-layer films and obtain high-performance transparent electrodes, the effects of silver (Ag) layer thickness and scan line spacing on optical and electrical properties of Ag/F-doped SnO 2 (FTO) bilayer composite thin films prepared by radio frequency (RF) magnetron sputtering and ultrasonic-vibration-assisted laser annealing were investigated. The results indicate that as compared to the untreated FTO single-layer film, the Ag/FTO composite film displays a dramatic decrease in sheet resistance with even an improvement in transparency when the Ag layer thickness reaches 5 nm under the combined effect of laser annealing and ultrasonic vibration. Furthermore, the XRD and SEM analyses reveal that only using the moderate scan line spacing during ultrasonic-vibration-assisted laser annealing can contribute to the grain growth of the films. The Ag/FTO film with an Ag layer thickness of 5 nm and a scan line spacing of 20 μm shows a remarkable overall performance with an increased figure of merit of 2.13 × 10−2 Ω−1 comparing to 1.13 × 10−2 Ω−1 for the untreated FTO film. This work confirms the opportunity of combining Ag layer deposition and ultrasonic-vibration-assisted laser annealing in significantly improving both optical and electrical properties of FTO single-layer films, providing a promising alternative to the conventional ITO transparent electrodes. • Ag layer deposition and ultrasonic-vibration-assisted laser annealing were combined. • Ag/FTO composite thin films with improved uniformity and compactness were prepared. • Laser annealing with ultrasonic vibration improved the film photoelectric properties. • The optimal Ag layer thickness (5 nm) and scan line spacing (20 μm) were determined. • The as-obtained Ag/FTO film showed better photoelectric properties than the FTO film. [ABSTRACT FROM AUTHOR]

• A feasible quasi-vacuum laser annealing method was proposed for TCO-based films. • The quasi-vacuum state was formed by covering a transparent PET sheet on an FTO film. • PET carbonization and FTO ablation phenomena during laser annealing were studied. • Optimal PET-assisted laser annealing parameters were determined based on processing map. • PET-assisted laser annealing surpassed laser annealing in improving film performance. This work presents a simple and efficient quasi-vacuum laser annealing method for photoelectric performance optimization of SnO 2 :F (FTO) films. This method uses a transparent polyethylene terephthalate (PET) sheet to form a quasi-vacuum environment on the film surface, which was conducive to restraining the rapid loss of laser energy and thus reinforcing the laser annealing effect. It was found that the PET-assisted laser annealing effect was closely related to the transformation of the PET sheet caused by using different laser pulse energies and defocusing amounts, and thus resulted in different surface morphology features of the FTO films. The ideal laser annealing effect could be achieved only through entirely ashing the pregenerated PET carbonized residues and avoiding laser ablation of the FTO layer. Based on the established processing map, the optimal laser pulse energy and defocusing amount for PET-assisted laser annealing of the FTO films were determined to be 90 μJ and 0.6 mm, respectively. The as-obtained FTO film was confirmed to have the best overall performance with the highest average visible transmittance of 84.5%, the lowest sheet resistance of 6.8 Ω/sq and the highest figure of merit of 2.73 × 10−2 Ω−1, indicating the prominent application superiority of PET-assisted laser annealing. [ABSTRACT FROM AUTHOR]

Abstract ZnO/Al/Cu/ZnO multilayer films were deposited on flexible polyethylene terephthalate (PET) substrates by radio frequency (RF) magnetron sputtering. The overall thickness of the intermediate Al and Cu metal layers maintained at 8 nm. The four different Al/Cu thickness ratios were 7:1, 6:2, 5:3 and 4:4. Other four reference samples were prepared by using the same process, i.e. ZnO single-layer film, ZnO/Al 8 (8-nm-thick Al layer, the same below)/ZnO, ZnO/Cu 8 /ZnO and ZnO/Cu 2 /Al 6 /ZnO multilayer films. The effects of Al/Cu thickness ratio and deposition sequence of Al and Cu layers were investigated. The results revealed that with the increase of Cu layer thickness, sheet resistance of the multilayer film decreased, while transmittance increased first and then decreased. The ZnO/Al 6 /Cu 2 /ZnO multilayer film with a sheet resistance of 108 Ω/sq and an average visible transmittance of 84.73% had the optimum overall photoelectric property, being confirmed by the highest figure of merit of 1.77 × 10–3 Ω–1. Furthermore, ZnO/Cu 2 /Al 6 /ZnO and ZnO/Al 6 /Cu 2 /ZnO multilayer films exhibited almost the same average visible transmittance and sheet resistance, implying that the deposition sequence of Al and Cu layers has little influence on photoelectric properties. It is demonstrated that ZnO/Al/Cu/ZnO multilayer flexible films have great potential in various fields. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A simple transparent cover-assisted laser annealing method was employed on FTO films. • The presence of coverslip or PET significantly affected the film surface morphology. • Coverslip- or PET-assisted laser annealing greatly increased grain size of the film. • The PET-assisted laser annealed FTO film exhibited the best photoelectric property. Abstract A simple transparent cover-assisted laser annealing strategy, which used a coverglass or a PET sheet as the transparent cover, was proposed to improve photoelectric properties of fluorine-doped tin oxide (FTO) thin films. Pure laser annealing was also performed for comparison. Transparent cover-assisted laser annealing was found to be more effective for producing densely distributed particles, decreasing surface roughness and increasing grain size, thus enhancing transmittance and conductivity of the film. More importantly, compared with coverglass-assisted laser annealing, PET-assisted laser annealing enabled the film surface to be covered with more uniform and denser particles and exhibit a remarkable increase in grain size. Therefore the film had the highest total transmittance of 84.32%, the highest specular transmittance of 75.88%, a slightly decreased haze of 10.01% and the lowest sheet resistance of 7.36 Ω/sq. The simple PET-assisted laser annealing method may be a promising substitution for the conventional laser annealing treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu/Ag/AZO multilayer films were subjected to nanosecond pulsed laser annealing. • Effects of laser fluence (F) and scanning speed (S) on film properties were studied. • Laser annealing under moderate laser parameters promoted grain growth in the film. • The film under L = 1.0 J/cm2 and S = 10 mm/s had the optimal comprehensive property. • The laser-annealed Cu/Ag/AZO L transparent heater had excellent heating performances. Nanosecond pulsed laser annealing was performed to improve optical and electrical properties of the Cu/Ag/AZO multilayer films. Different laser fluences (L) and scanning speeds (S) were selected to investigate their influences on optical transparency and electrical conductivity of the films. The results revealed that laser annealing under L = 1.0 J/cm2 and S = 10 mm/s effectively promoted grain growth in the film and caused formation of significantly enlarged particles with a more uniform distribution on the film surface. The as-obtained Cu/Ag/AZO multilayer film possessed the optimal comprehensive property with the highest figure of merit of 3.58 × 10–2 Ω−1, far outperforming the unannealed Cu/Ag/AZO multilayer film (1.92 × 10–2 Ω−1). Subsequently, this film was chosen to fabricate a transparent heater, which exhibited excellent heating performance (saturated temperature: 104.9 ℃; response time: 120 s; applied voltage: 5 V) and heating stability. Its deicing availability was also shown by a deicing test. [ABSTRACT FROM AUTHOR]