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we are studying the inhomogeneity of the thickness properties of the deposited ZnO:B film Based on glass substrates obtained by low pressure chemical viper deposition (LPCVD), which allow us to develop recommendations for optimizing the technological process for obtaining ZnO layers with characteristics that best meet the requirements for use in solar modules.The haze factor of the deposited ZnO film on a glass substrate with a size of 1300x1100 mm is 26.6% (average for glass) and 34% (maximum value), the average value of the value of the surface resistance is 17.6 O which is matching with a film thickness of 1657 nm, which leads to an improvement in the efficiency of the solar cell from (9.04%-10.1%).

With the development of lightweight and flexible electronics, flexible transparent electrodes (TEs) have attracted huge attention in both academia and industry, and play a central role in high-performance flexible electronics. As a kind of emerging conducting material for TEs, metallic micro–nano architectures (MMNAs) possess both low sheet resistance and high optical transmittance. In addition, the high flexibility and low-cost solution processing make MMNAs promising candidates to replace the traditional conductive metal oxides, which suffer from the high-cost fabrication process and low conductivity on flexible substrates. In this review, we summarize the recent progress in flexible TEs based on MMNAs, as well as the comparison to other conducting materials, such as conducting polymers, graphene, carbon nanotubes, etc. Specially, we highlight the applications of flexible TEs based on MMNAs in perovskite solar cells (PSCs), including inverted PSCs, conventional PSCs, and semi-transparent PSCs. Finally, the challenges and prospects in this field are proposed.

Here, we report the growth of improved quality graphene thin film by a modified method using shellac as a low-cost and eco-friendly carbon source on three different substrates. We chose stainless steel (SS 316) plates used as a solid surface, nickel foam (NiF) representative of a solid porous substrate, and carbon fiber fabric (CFF) as a porous-flexible substrate. The graphene characteristic is found to be substrate-dependent in this single-step method. Uniform multilayer graphene is grown on SS316. In the case of Ni foam, the as-synthesized graphene exhibits high quality with relatively low defects. It was troublesome to grow uniform graphene on flexible CFF due to the low wettability of precursor solution. The substrate was required to modify with a thin (∼60 nm) layer of Ni deposition. The transfer-free method of graphene on CFF was assured by etching Ni via an acid treatment. Graphene coated SS316 used as bipolar plate exhibits superior corrosion resistance with corrosion current density Icorr ∼1.2 μA/cm2 and much lower interfacial contact resistance ICR ∼7.7 mΩ cm2. Graphene coated Ni foam was utilized as electrodes in supercapacitors which show large areal capacitance ∼1.7 F/cm2. Besides, graphene coated CFF shows sheet resistance ∼50% lower than that of uncoated CFF.

This paper proposes the use of superhydrophobic graphene/ceramic templates fabricated through laser texturing and patterning for the preparation of particulate drugs. A nanosecond pulse fiber laser was used to texture a graphene film coated on ceramic substrates for obtaining a superhydrophobic surface. Then, laser patterning was conducted on the laser-textured surface to define the diameter of the prepared particulate drugs. Laser-textured graphene/ceramic substrates with a laser areal fluence of 17.51 J/cm2 and a hatch distance of 0.01 mm exhibited a maximum water contact angle of 151.5°. This result was obtained because the laser-textured graphene films contained coral reef structures with nanoscale pores. Raman analyses indicated that the intensities of the G and 2D bands gradually decreased after the laser texturing and patterning processes. Moreover, the sheet resistance of the laser-textured and laser-patterned graphene films was larger than that of untextured ones because the thickness of the graphene films was reduced through laser thinning. The maximum heating temperature of the graphene-based heater was 140 °C for an input direct current voltage of 36 V. In addition, graphene-based self-heating devices were developed and successfully used to dry liquid roflumilast.

The emerging technique of carbonization of polyimide (PI) by direct laser writing receives great attention for its flexibility, versatility, and ease-of-patterning capability in creating a variety of functional laser-induced graphene (LIG) sensors and devices. LIG prepared by CO2 laser irradiating of the PI film is characterized by scanning electron microscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), specific surface area analyzer, synchronous thermal analysis, and Raman spectroscopy with the focus on investigating the effects of laser parameters (e.g. power, scanning speed) on the microstructure, thickness, and sheet resistance of LIG. Both TEM and XRD indicate that LIG is composed of many graphene layers with a layer spacing of 0.34 nm. The specific surface area of LIG decreases with the increase of laser power. The ratio of the thickness of LIG over the depth of the carbonized PI film as the expansion ratio characterizes the expansibility of LIG. The influence of laser scanning speed and off-focus value on the sheet resistance of LIG is explained by the superposition mechanism of laser scanning spots.

Current artificial magnetic conductor (AMC) designs use metallic patterns on rigid substrates and focus on shapes and sizes of AMC structures, rather than on material performance, which has hindered operation bandwidth and design flexibility. Here, we introduce printed graphene AMC-based broadband and flexible microwave radar absorbers, which not only redirect but also absorb the incident wave so to broaden the operation bandwidth. Contrasting to other reported works, the phase characteristics of the AMCs are realized through the control of the surface resistance provided by printed graphene laminates. We produced a variety of AMC structures, composed of printed graphene circular ring arrays with exactly the same shape and size, but different sheet resistances. By carefully designing the sheet resistance of printed graphene laminates, the optimized anti-phase reflection cancellation between AMCs can be achieved. With printed graphene AMCs and flexible dielectric substrate, the absorber presented in this work has a broadband effective absorption (above 90% absorptivity) from 7.58 GHz to 18 GHz, is polarization insensitive under normal incident and can work at relatively wide incident angles. Furthermore, this absorber is capable of bending easily with notable performance, which makes it ideal for applications with irregular and uneven shapes.

Previous studies indicate that the properties of graphene oxide (GO) can be significantly improved by enhancing its graphitic domain size through thermal diffusion and clustering of functional groups. Remarkably, this transition takes place below the decomposition temperature of the functional groups and thus allows fine tuning of graphitic domains without compromising with the functionality of GO. By studying the transformation of GO under mild thermal treatment, we directly observe this size enhancement of graphitic domains from originally ≤40 nm2 to >200 nm2 through an extensive transmission electron microscopy (TEM) study. Additionally, we confirm the integrity of the functional groups during this process by a comprehensive chemical analysis. A closer look into the process confirms the theoretical predicted relevance for the room temperature stability of GO and the development of the composition of functional groups is explained with reaction pathways from theoretical calculations. We further investigate the influence of enlarged graphitic domains on the hydration behaviour of GO and the catalytic performance of single atom catalysts supported by GO. Additionally, we show that the sheet resistance of GO is reduced by several orders of magnitude during the mild thermal annealing process.

Doped graphene could be of use in next-generation electronic and photonic devices. However, chemical doping cannot be precisely controlled in the material and leads to external disorder that diminishes carrier mobility and conductivity. Here we show that graphene can be efficiently doped using a monolayer of tungsten oxyselenide (TOS) that is created by oxidizing a monolayer of tungsten diselenide. When the TOS monolayer is in direct contact with graphene, a room-temperature mobility of 2,000 cm2 V−1 s−1 at a hole density of 3 × 1013 cm−2 is achieved. Hole density and mobility can also be controlled by inserting tungsten diselenide interlayers between TOS and graphene, where increasing the layers reduces the disorder. With four layers, a mobility value of around 24,000 cm2 V−1 s−1 is observed, approaching the limit set by acoustic phonon scattering, resulting in a sheet resistance below 50 Ω sq−1. To illustrate the potential of our approach, we show that TOS-doped graphene can be used as a transparent conductor in a near-infrared (1,550 nm) silicon nitride photonic waveguide and ring resonator. A monolayer of tungsten oxyselenide, created by oxidizing a layer of tungsten diselenide, can be used to efficiently dope graphene, leading to a room-temperature mobility of 2,000 cm2 V–1 s–1 at a hole density of 3 × 1013 cm–2.

We systemically investigated the effect of chip structures on the optical characteristics of micro-size LEDs. The total internal reflection (TIR) can be improved by selecting a suitable chip structure, thereby increasing the light efficiency. The saturation light output power (LOP) of the micro-size LED using pentagon-type structure is 44.78 mW, an increase of 6.08% compared with that of micro-size LED using circular-type structure. Simulation and experimental results indicate that chip structure of pentagon-type can effectively enhance the light extraction from the top or side of the micro-size LED.

Highlights Dopant-tunable transparent conductive oxide (≤ 50 nm) fabricated via electric-field-driven metal implantation (m-TCOs; m= Ni, Ag, and Cu) is demonstrated.The m-TCOs exhibit ultrahigh transparency, low sheet resistance, and broad work function tunability, leading to outstanding performance in various optoelectronic devices.The work function change is attributed to the interstitial metal atoms that provide the empty d-orbital, resulting in the shift of the Fermi level. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00735-y., Ultrathin film-based transparent conductive oxides (TCOs) with a broad work function (WF) tunability are highly demanded for efficient energy conversion devices. However, reducing the film thickness below 50 nm is limited due to rapidly increasing resistance; furthermore, introducing dopants into TCOs such as indium tin oxide (ITO) to reduce the resistance decreases the transparency due to a trade-off between the two quantities. Herein, we demonstrate dopant-tunable ultrathin (≤ 50 nm) TCOs fabricated via electric field-driven metal implantation (m-TCOs; m = Ni, Ag, and Cu) without compromising their innate electrical and optical properties. The m-TCOs exhibit a broad WF variation (0.97 eV), high transmittance in the UV to visible range (89–93% at 365 nm), and low sheet resistance (30–60 Ω cm−2). Experimental and theoretical analyses show that interstitial metal atoms mainly affect the change in the WF without substantial losses in optical transparency. The m-ITOs are employed as anode or cathode electrodes for organic light-emitting diodes (LEDs), inorganic UV LEDs, and organic photovoltaics for their universal use, leading to outstanding performances, even without hole injection layer for OLED through the WF-tailored Ni-ITO. These results verify the proposed m-TCOs enable effective carrier transport and light extraction beyond the limits of traditional TCOs. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00735-y.

Synthesis of graphene by reducing graphene oxide is the most propitious route for bulk graphene production. Reduction using eco-friendly techniques is more feasible to alleviate toxic chemicals use. Hence, determining the reduction potency of natural substances is vital for further development in the rGO synthesis process. In this work, an experimental investigation was carried out to determine the reduction efficiencies of various natural and thermal reduction techniques. The results were compared with GO reduced with synthetic routes. To ensure accurate determination of reduction potential, constant reaction parameters and the same GO batch synthesized were used. Thorough sample characterization was carried out using FTIR, XPS, FESEM, Raman spectroscopy, XRD and sheet resistance measurements. Results showed that among natural substances, tea powder showed better reduction efficiencies with 13 folds increase in electrical conductivity, whereas synthetic routes showed more than 29 folds increase in the electrical conductivity values as compared to unreduced GO samples. The C/O ratio quantified from XPS analysis was found to be 2.83, 2.98, 3.88 and 6.34 for reduction carried out using lemon extract, coffee, tea powder and direct thermal treatment, respectively. Based on the results, an eco-friendly reduction route using natural substances has the potential for efficient reduction; however, it needs further optimization.

Reduced graphene oxide (rGO) is among only a few p-type transparent conductors. This article describes the use of pre-decoration of gold nanoparticles (AuNPs) to tune the optoelectronic properties of rGO film. High-purity Au is sputtered on GO film before the thermal reduction process at 825°C in a H2/CH4 environment. For the optimum 30 s Au sputtering, a high-temperature process transformed the Au nanoballs into nanowires. These conditions resulted in the maximum hole mobility of 158.99 cm2 V−1 s−1 and the minimum sheet resistance of 325.82 Ω□−1. The degree of reduction for the rGO-Au(30s) sample was the highest, since it had the lowest optical transmittance of 0.871 and the lowest bandgap of 3.75 eV. It thus represents the best p-type transparent conductor, with a figure of merit σdc/σop of approximately 8.11. The deconvoluted Raman fit elaborates more on the elimination of defect components on the rGO samples. The integrated area ratio for several defect peaks over a pristine peak was the lowest for the rGO-Au(30s), at 3.98. The AuNPs intervened in the reduction process by repairing the lattice defects for the in-plane carbon sp2, edge, amorphous phase, and out-of-plane sp2–sp3. This was responsible for the great improvement in the carrier transport mechanism and the value of σdc/σop.

We report a viable method to produce nanocrystalline graphene films on polycrystalline nickel (Ni) with enhanced N doping at low temperatures by a cold-wall plasma-assisted chemical vapor deposition (CVD) method. The growth of nanocrystalline graphene films was carried out in a benzene/ammonia/argon (C6H6/NH3/Ar) system, in which the temperature of the substrate heated by Joule heating can be further lowered to 100 °C to achieve a low sheet resistance of 3.3 kΩ sq-1 at a high optical transmittance of 97.2%. The morphological, structural, and electrical properties and the chemical compositions of the obtained N-doped nanocrystalline graphene films can be tailored by controlling the growth parameters. An increase in the concentration of atomic N from 1.42 to 11.28 atomic percent (at.%) is expected due to the synergetic effects of a high NH3/Ar ratio and plasma power. The possible growth mechanism of nanocrystalline graphene films is also discussed to understand the basic chemical reactions that occur at such low temperatures with the presence of plasma as well as the formation of pyridinic-N- and pyrrolic-N-dominated nanocrystalline graphene. The realization of nanocrystalline graphene films with enhanced N doping at 100 °C may open great potential in developing future transparent nanodevices.

In this work, nanofibrillated cellulose (NFC), LiFePO4 (LFP), and graphene (GR) were used as raw materials to prepare a flexible self-supporting electrode. NFC shows excellent mechanical properties and flexibility. NFC is used as the skeleton of the flexible electrode, coupling LFP and GR to form a conductive network structure. The Flexible electrodes show excellent flexibility and bendability. The mass of the flexible electrode no longer decreased significantly at temperature higher than 400 °C. The final residual rate of the flexible electrode is about 58%. The surface resistance of the flexible electrode is found to decrease by 93% with the content of LFP increasing from 25 to 45 wt%. The flexible electrode also shows higher electrochemical reaction activity and higher reversibility of Li+ extraction/intercalation with the increase of LFP and GR. At 0.1 C rate, the first discharge capacity is 121.47 mAh g−1, 146.76 mAh g−1 and 167.74 mAh g−1 for NFC/GR/LFP flexible electrode with 25 wt%, 35 wt%, and 45 wt% LFP, respectively. After 60 cycles of cycling, the capacity retention rate remains above 98%. Under 5 C rate, the first discharge capacity of these electrodes decrease to 29.87 mAh g−1, 77.41 mAh g−1, 99.84 mAh g−1, respectively, and after 770 cycles, the capacity retention rate is still above 90%. The AC impedance of the NFC/GR/LFP flexible electrodes with LFP content of 25 wt%, 35 wt%, and 45 wt% is 40 Ω, 15 Ω, and 9 Ω, respectively. The above results show that the flexible electrode exhibits excellent mechanical and electrochemical properties. The flexible electrode shows very high capacity retention rate no matter at low scan rate and or high scan rate. The cycle stability can be further enhanced by increasing the loading of active materials.

The enhanced surface area of silicon nanotexture is an important metric for solar cell integration as it affects multiple properties including optical reflectance, dopant diffusion, and surface recombination. Silicon nanotexture is typically characterized by its surface-area-to-projected-area ratio or enhanced area factor (EAF). However, traditional approaches for measuring EAF provide limited statistics, making correlation studies difficult. In this article, silicon's dominant ultraviolet reflectance peak, R(E2), which is very sensitive to surface etching, is applied to EAF spatial mapping. A clear decay correlation between R(E2) and EAF is shown for multiple textures created using reactive ion etching and metal catalyzed chemical etching. This correlation is applied to R(280 nm) reflectance mapping to yield accurate, high-resolution full-wafer EAF spatial mapping of silicon nanotextures. R(280 nm) mapping is also shown to be sensitive enough to correlate the impact of nanotexture spatial variation on post-diffusion sheet resistance. Finite-difference time-domain simulations of several nanoscale pyramid textures confirm a decay band for R(E2) versus EAF, consistent with our measurements. We suggest that R(E2) mapping may prove useful for other silicon nanotexture properties and applications where EAF is important.

Liquid precursors are of high practical interest for the chemical vapor deposition (CVD) of graphene and related materials. In terms of cost, safety and technological operability, the liquids are significantly more attractive than the conventional gas precursors. Another challenge to the technology is the direct deposition of carbon films on dielectric substrates without the transfer procedure. In the present work, we study the synthesis of graphene-like films (GLFs) on sapphire and SiO2/Si from two liquid precursors: acetone and isopropanol. GLFs in this work are defined as multi-layer graphene films with a crystallite size of several tens of nm. The films synthesized by CVD at different temperatures were characterized by the optical transmittance and sheet resistance; the structure of the films was studied by Raman spectroscopy. We show that such films have superior characteristics as compared to most literature data on direct CVD deposition from oxygen-containing liquid precursors. The films can be grown selectively on exposed areas of the e-beam pre-patterned substrate at specific deposition conditions. We demonstrate this by selectively growing a Hall bar microstructure for carrier mobility measurements.

In this work, the thermal stability issue of ultrathin Ti-based silicide (TiSix) in prospective dynamic random access memory (DRAM) peripheral 3D FinFET transistors was systematically studied. As-prepared TiSix/n+-Si contacts and ultrathin TiSix films with different annealing temperatures, were characterized by means of specific contact resistivity (ρc), sheet resistance measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). It is shown that the specific contact resistivity (ρc) for TiSix/n+-Si contacts gradually degrades with the increase of annealing temperature in the range 450–900 °C. In addition, it is revealed that though thick TiSi2 is conventionally known as thermal stable silicide, the agglomeration of ultrathin TiSix in the source/drain regions of 3D FinFETs still occurs after DRAM annealing typically at 750 °C for few hours. This agglomeration is thought to be responsible for the deterioration of ρc for TiSix/n+-Si contacts.

Atomically precise, δ-doped structures forming electronic devices in Si have been routinely fabricated in recent years by using depassivation lithography in a scanning tunneling microscope (STM). While H-based precursor/monatomic resist chemistries for incorporation of donor atoms have dominated these efforts, the use of halogen-based chemistries offers a promising path toward atomic-scale manufacturing of acceptor-based devices. Here, B-doped δ-layers were fabricated in Si(100) by using BCl3 as an acceptor dopant precursor in ultrahigh vacuum. Additionally, we demonstrate compatibility of BCl3 with both H and Cl monatomic resists to achieve area-selective deposition on Si. In comparison to bare Si, BCl3 adsorption selectivity ratios for H- and Cl-passivated Si were determined by secondary ion mass spectrometry depth profiling (SIMS) to be 310(10):1 and 1529(5):1, respectively. STM imaging revealed that BCl3 adsorbed readily on bare Si at room temperature, with SIMS measurements indicating a peak B concentration greater than 1.2(1) × 1021 cm-3 with a total areal dose of 1.85(1) × 1014 cm-2 resulting from a 30 langmuir BCl3 dose at 150 °C. In addition, SIMS showed a δ-layer thickness of ∼0.5 nm. Hall bar measurements of a similar sample were performed at 3.0 K, revealing a sheet resistance of ρ□ = 1.9099(4) kΩ □-1, a hole carrier concentration of p = 1.90(2) × 1014 cm-2, and a hole mobility of μ = 38.0(4) cm2 V-1 s-1 without performing an incorporation anneal. Finally, 15 nm wide B δ-doped nanowires were fabricated from BCl3 and were found to exhibit ohmic conduction. This validates the use of BCl3 as a dopant precursor for atomic-precision fabrication of acceptor-doped devices in Si and enables development of simultaneous n- and p-type doped bipolar devices.

We have developed a 6-kA/cm² superconducting integrated circuit fabrication process toward large-scale single flux quantum digital circuits. To evaluate the process reliability and controllability, a set of process control monitors (PCMs) for monitoring fabrication and design parameters was designed and tested. Fabrication parameters, for example, film thicknesses and etched depths of the layers, were measured by testing specific patterns during fabrication. Design parameters such as the critical current density J c, normal-state resistance R n and actual sizes of Josephson junctions, the sheet resistance of Mo resistor R sh, and the penetration depth of Nb films were evaluated by electrically characterizing PCM circuits after fabrication. We also monitored superconducting critical currents for vias and Nb lines, and insulation properties between the metal layers systematically.

A single-step reduction and patterning technique that involves high-pulse nanosecond fiber laser irradiation was used to reduce graphene oxide films (GOFs) for use in ceramic-based heaters. Laser reduction of GOFs was performed at a laser power, scan speed, pulse repetition frequency, and laser scan pitch of 2.2–4.1 W, 150–500 mm/s, 750 kHz, and 10 μm, respectively. The optimal intensity ratios of the D to G band (RD/G) and the 2D to G band (R2D/G) of reduced GOFs (RGOFs), obtained from Raman spectra, were 0.251 and 0.587, respectively. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses revealed that oxygen-containing functional groups in RGOFs coated onto ceramic substrates were removed by increasing the average laser power and decreasing the laser scanning speed. Moreover, the typical RGOFs exhibited a lowest sheet resistance of 22.75 ± 2.75 Ω/□, which was achieved with an average laser power and scan speed of 3.35 W and 300 mm/s, respectively. The highest temperature of the typical laser-patterned RGOFs was approximately 123.3 °C, which occurred when the RGOFs were produced using a laser power, scan speed, and applied direct current voltage of 3.27 W, 200 mm/s, and 10 V, respectively.

Laser-induced graphitic carbon (LIGC) is a promising technology to manufacture conductive carbon in a cost-effective manner on a flexible substrate with a scanned laser. One limitation preventing the widespread adoption of LIGC in electronic devices and circuits has been its relatively high sheet resistance. Here, we report the lowest sheet resistance to date for LIGC engraved on flexible polyimide of 6.14 ± 0.11 Ω/□. Several general strategies are identified to minimize sheet resistance. Most importantly, the total laser energy per unit area delivered to the substrate needs to be maximized. This can be achieved by increasing laser power, decreasing laser scan speed and increasing overlap between adjacent pulses. Pulse overlap can be increased by increasing linewidth (raster rather than vector mode) and increasing the dots per cm resolution, i.e., decreasing spacing between pulses, which also improves LIGC uniformity. Further, decreasing scan speed increases the ablation threshold because of increased cooling between pulses enabling more energy to be delivered without the material ablating. These insights were obtained using a combination of electrical measurements, thermal modeling and material characterization. With optimized energy delivery, a domain size (La) of about 60 nm was obtained, which highlights the high quality of the obtained LIGC material.

We have developed a fabrication technology for superconducting integrated circuits with Nb-based Josephson junctions. The standard fabrication process with 10 mask levels includes 3 Nb superconducting layers and a Mo resistor layer. The influence of deposition parameters on film stress, electrical properties, and surface roughness were studied systematically. High quality Nb, Al, Mo, and SiO2 films were successfully deposited for the subsequent fabrication of circuits. The circuit fabrication started with the fabrication of Mo resistors with a target sheet resistance R sh of 2 Ω, followed by the deposition of Nb/Al-AlO x /Nb trilayer Josephson-junction. The target critical current density J c was set at 6 kA/cm2. Small-scale circuits such as our standard library cells have been successfully fabricated and tested, confirming the capability of our fabrication technology for superconducting integrated circuits.

The effects of total dose irradiation on graphene-based Hall sensors were investigated by 60Co $\gamma $ -ray in this paper. The basic electrical parameters of the sensors were measured before and after $\gamma $ -ray irradiation up to 1 Mrad(Si). Decreases in the Hall voltage, linearity and current-related sensitivity in response to $\gamma $ -ray irradiation were observed. With the help of Raman spectroscopy and X-ray photoelectron spectra (XPS), the degradation after irradiation was attributed to the introduction of defects and the increase in doping concentrations in the graphene layer. Moreover, the introduction of defects and impurities enhanced the Coulomb scattering of carriers, resulting in a decrease in mobility, which in turn affected the sheet resistance. This work provides an insight into the interactions of ionizing irradiation with graphene-based Hall sensors, which could be applied in space or other irradiation sensitive applications.

In order to improve the quality of n+ emitter fabricated by phosphorus doping, SiO2 nanospheres were added into a phosphoric acid solution for spin-on doping. Through a complete analysis of the trade-off between the diffusion uniformity and sheet resistance, the particle size of SiO2 nanospheres is selected to be 230 nm. It is found that with the increase of phosphoric acid concentration from 50% to 85%, the average sheet resistance decreases from 128.5 Ω/sq to 18.1 Ω/sq, and the diffusion uniformity increased from 95.2% to 98.5%. In a large concentration range, the surface doping concentration of the emitter will increase with phosphoric acid, but when the concentration of phosphoric acid reaches 80%, the surface doping concentration will be almost unchanged. Nevertheless, different from above, the p-n junction depth has little dependence on the phosphoric acid concentration. Moreover, the efficiencies in the solar cell center and edge are enhanced by 40.54% and 88.08% respectively using SiO2 nanospheres assisted diffusion.

In this report we investigate structural and electrical properties of epitaxial Chemical Vapor Deposition quasi-free-standing graphene on an unintentionally-doped homoepitaxial layer grown on a conducting 4H–SiC substrate 4° off-axis from the basal [0001] direction towards [11-20]. Due to high density of SiC vicinal surfaces the deposited graphene is densely stepped and gains unique characteristics. Its morphology is studied with atomic force and scanning electron microscopy. Its few-layer character and p-type conductance are deduced from a Raman map and its layers structure determined from a high-resolution X-ray diffraction pattern. Transport properties of the graphene are estimated through Hall effect measurements between 100 and 350 K. The results reveal an unusually low sheet resistance below 100 Ω/sq and high hole concentration of the order of 1015 cm−2. We find that the material's electrical properties resemble those of an epitaxially-grown SiC PIN diode, making it an attractive platform for the semiconductor devices technology.

In order to ensure high-performance semitransparent perovskite solar cells (ST-PSCs), the deposition of high-quality scalable transparent cathodes on ST-PSCs at room temperature is necessary. In this study, we designed an amorphous InGaTiO (IGTO) electrode, prepared by linear facing target sputtering (LFTS) as a transparent cathode for ST-PSCs. Even in the room temperature sputtering process, the amorphous IGTO cathode showed a low sheet resistance of 9.895 Ohm/square and a high optical transmittance of 87.53% without the occurrence of in situ or postannealing, unlike Sn-doped In2O3 (ITO) electrodes. Due to its complete amorphous structure and low energy sputtering, the amorphous IGTO electrode showed superior mechanical properties, when compared to other typical crystalline ITO films. Additionally, the LFTS process led to a low energy deposition of the amorphous IGTO cathode on ST-PSCs, and did not result in plasma damage on perovskite active layers, which is often typical in conventional situations of direct current sputtering. On the basis of these optimized plasma damage-free sputtering conditions, we examined the feasibility of LFTS-grown IGTO cathodes for ST-PSCs. In our results, we observed that a similar performance of the ST-PSC with an IGTO cathode with the opaque PSC with Ag cathode, indicated that amorphous IGTO cathode is a prospective transparent cathode for ST-PSCs on both rigid or flexible substrates.

Printed piezoresistive strain sensors based on stretchable roll-to-roll screen-printed silver electrodes on polydimethylsiloxane substrates and inkjet-deposited single-wall carbon nanotube micropatterns are demonstrated in this work. With the optimization of surface wetting and inkjet printing parameters, well-defined microscopic line patterns of the nanotubes with a sheet resistance of

Realization of graphene-based sensors and electronic devices remains challenging, in part due to integration challenges with current fabrication and manufacturing processes. Thus, scalable methods for in situ fabrication of high-quality graphene-like materials are essential. Low-cost CO2 laser engravers can be used for site-selective conversion of polyimide under ambient conditions to create 3-D, rotationally disordered, few-layer, porous, graphene-like electrodes. However, the influences of non-linear parameter terms and interactions between key parameters on the graphitization process present challenges for rapid, resource-efficient optimization. An iterative optimization strategy was developed to identify promising regions in parameter space for two key parameters, laser power and scan speed, with the goal of optimizing electrode performance while maximizing scan speed and hence fabrication throughput. The strategy employed iterations of Design of Experiments Response Surface (DoE-RS) methods combined with choices of readily measurable parameters to minimize measurement resources and time. The initial DoE-RS experiment set employed visual response parameters, while subsequent iterations used sheet resistance as the optimization parameter. The final model clearly demonstrates that laser graphitization through raster scanning is a highly non-linear process requiring polynomial terms in scan speed and laser power up to fifth order. Two regions of interest in parameter space were identified using this strategy: Region 1 represents the global minimum for sheet resistance for this laser (∼16 Ω/sq), found at a low scan speed (70 mm/s) and a low average power (2.1 W) . Region 2 is a local minimum for sheet resistance (36 Ω/sq), found at higher values for scan speed (340 mm/s) and average power (3.4 W), allowing ∼5-fold reduction in write time. Importantly, these minima do not correspond to constant ratios of average laser power to scan speed. This highlights the benefits of DoE-RS methods in rapid identification of optimum parameter combinations that would be difficult to discover using traditional one-factor-at-a-time optimization. Verification data from Raman spectroscopy showed sharp 2D peaks with mean full-width-at-half-maximum intensity values

Superhydrophobic materials with special functions of electrical conductivity, magnetism, photothermal conversion and others have been paid considerable attention in the emerging fields including wearable electronics, long-distance manipulation and seawater desalination. Herein, we report a facile approach to fabricate superhydrophobic and conductive cotton fabric (CF) for piezoresistive pressure sensor. It was based on the utilization of the reduced graphene oxide (rGO) layer on CF to form conductive pathways. Meanwhile, the in-situ generated hybrid of polydimethylsiloxane (PDMS)/titanium dioxide (TiO2) on rGO layer through the hydrolysis-condensation and cross-linking reactions between dihydroxyl-terminated PDMS and tetrabutyl titanate played the role of constructing rough structure and decreasing surface energy. The fabricated PDMS/TiO2@rGO coated CF exhibited a high water contact angle of 159.3° and possessed outstanding self-cleaning ability. Interestingly, owing to the existence of TiO2, the CF also had the capability to degrade organic contaminations and the degradation rate reached 96.4% after being exposed under UV light for 90 min. In addition, the PDMS/TiO2@rGO coated CF with a low electrical surface resistance of 0.76 kΩ cm−1 was utilized to design and prepare a multilayer piezoresistive pressure sensor by means of the large number of air gaps between the fibers and the increase of contact points under external pressure. The sensor showed high sensitivity, fast response and good repeatability, and was successfully applied for detecting different human behaviors including pulse, voice recognition, and body motion. Our findings conceivably stand out as a new methodology to fabricate functional superhydrophobic materials and surfaces for practical applications in the fields of electronic skin, human healthcare, interactive wearable device and smart robotics.

Mass production of defect-free single-layer graphene flakes (SLGFs) by a cost-effective approach is still very challenging. Here, we report such single-layer graphene flakes (SLGFs) (>90%) prepared by a nondestructive, energy-efficient, and easy up-scalable physical approach. These high-quality graphene flakes are attributed to a novel 10 s microwave-modulated solid-state approach, which not only fast exfoliates graphite in air but also self-heals the surface of graphite to remove the impurities. The fabricated high-quality graphene films (∼200 nm) exhibit a sheet resistance of ∼280 Ω/sq without any chemical or physical post-treatment. Furthermore, graphene-incorporated Ni-Fe electrodes represent a remarkable ∼140 mA/cm2 current for the catalytic water oxidation reaction compared with the pristine Ni-Fe electrode (∼10 mA/cm2) and a 120 mV cathodic shift in onset potential under identical experimental conditions, together with a faradic efficiency of >90% for an ideal ratio of H2 and O2 production from water. All these excellent performances are attributed to extremely high conductivity of the defect-free graphene flakes.

In this work we compare seven different types of natural and synthetic graphite particles and examine how their integration into the cathode of carbon-based perovskite solar cells (C–PSCs) is influencing their opto-electronic properties. By combining x-ray diffraction, Raman spectroscopy and 4-point probe measurements we show that the differences in graphite crystallinity significantly affect the sheet resistance of the carbon-based cathode. The most conductive carbon-based film with an exceptional sheet resistance of 4 Ω/sq. have been produced from scaly graphite with the crystallite dimensions of La = 60.6 nm and Lc = 28.6 nm. Electrochemical Impedance Spectroscopy further revealed that charge transfer resistance at the perovskite/carbon contact differ for each graphite type. Overall, the pyrolytic graphite was found to be the best compromise between high conductivity and low charge transfer resistance leading to least series resistance losses and a fill factor (FF) above 74% (in perovskite solar cells with area of 0.64 cm2). However, an overall efficient hole extraction and lower non-radiative charge recombination in C–PSCs with scaly graphite resulted in the highest average power conversion efficiency and a champion device reaching 14.63%. All the C–PSCs show exceptional moisture stability for 5,000 h under ambient condition, with a PCE decrease of less than 3%.

Inkjet printing has proven to be a promising alternative method in the fabrication of printed electronics, besides screen printing and photolithography etching. In this work, we characterize the electrical performance of inkjet printed circuits on flexible PET and glossy photo paper. The electrical circuits were printed using a commercial Epson L310 piezoelectric printer, and the NB series silver ink and chemical-sintering PET substrate from Mitsubishi Paper Mills. This method allows rapid prototyping of electronic circuits (~ 30 min design, ~ 5 s fabrication) and quick iteration of prototypes. The system has a resolution of 250 µm electrodes and 300 µm electrical gaps, and on average, 1.5 ± 0.2 µm in thickness. The effect of printing on different substrates, geometry and overprinting on sheet resistance was also studied. It was found that double printing produced better electrodes with lower resistances. A stable conducting circuit has a sheet resistivity of

Graphene oxide (GO), reduced graphene oxide (rGO) and carbon nanotubes (CNTs) have their own advantages in electrical, optical, thermal and mechanical properties. An effective combination of these materials is ideal for preparing transparent conductive films to replace the traditional indium tin oxide films. At present, the preparation conditions of rGO are usually harsh and some of them have toxic effects. In this paper, an SnCl2/ethanol solution was selected as the reductant because it requires mild reaction conditions and no harmful products are produced. The whole process of rGO preparation was convenient, fast and environmentally friendly. Then, SEM, XPS, Raman, and XRD were used to verify the high reduction efficiency. CNTs were introduced to improve the film conductive property. The transmittance and sheet resistance were the criteria used to choose the reduction time and the content ratios of GO/CNT. Thanks to the post-treatment of nitric acid, not only the by-product (SnO2) and dispersant in the film are removed, but also the doping effect occurs, which are all conducive to reducing the sheet resistances of films. Ultimately, by combining rGO, GO and CNTs, transparent conductive films with a bilayer and three-dimensional structure were prepared, and they exhibited high transmittance and low sheet resistance (58.8 Ω/sq. at 83.45 T%, 47.5 Ω/sq. at 79.07 T%), with corresponding $${{\sigma_{dc} } \mathord{\left/ {\vphantom {{\sigma_{dc} } {\sigma_{opt} }}} \right. \kern-\nulldelimiterspace} {\sigma_{opt} }}$$ σ dc / σ opt values of 33.8 and 31.8, respectively. In addition, GO and rGO can modify the surface and reduce the film surface roughness. The transparent conductive films are expected to be used in photoelectric devices.

The object of research are samples of nonvolatile electrically alterable memory elements (memristors) based on TiN–TiO2–SiO2–W open “sandwich” structures, in which conductive nanostructures with electrically alterable characteristics are formed by the electroformation. The effect of the oxygen pressure and the electroformation conditions on the switching of the memory element is investigated. With the new experimental material, the earlier established character of the dependence of the oxygen threshold pressure (Pth) on the limiting current of switching (Ilim) for the pulse switching on of a memory element is confirmed. A shift in the Pth(Ilim) curve for different electroformation conditions, which can be explained by the corresponding change in the size of the conductive nanostructure, is demonstrated. Based on the obtained experimental data, changes in the size and specific surface resistance of the material of the conductive medium with varying limiting current of the electroformation Ilimf are estimated, which reveals an increase in the compactness of the nanostructure with a decreasing current. The earlier proposed mechanisms of the processes are clarified. A well-grounded method of the choice of the conditions of the electroformation for open sandwich structures is devised.

MXene is a generic name for a large family of two-dimensional transition metal carbides or nitrides, which show great promise in the field of transparent supercapacitors. However, the manufacturing of supercapacitor electrodes with a high charge storage capacity and desirable transmittance is a challenging task. Herein, a low-cost, large-scale, and rapid preparation of flexible and transparent MXene films via inkjet printing is reported. The MXene films realized the sheet resistance (Rs) of 1.66 ± 0.16 MΩ sq-1 to 1.47 ± 0.1 kΩ sq-1 at the transmissivity of 87-24% (λ = 550 nm), respectively, corresponding to the figure of merit (the ratio of electronic to optical conductivity, σDC/σOP) of ∼0.0012 to 0.13. Furthermore, the potential of inkjet-printed transparent MXene films in transparent supercapacitors was assessed by electrochemical characterization. The MXene film, with a transmittance of 24%, exhibited a superior areal capacitance of 887.5 μF cm-2 and retained 85% of the initial capacitance after 10,000 charge/discharge cycles at the scan rate of 10 mV s-1. Interestingly, the areal capacitance (192 μF cm-2) of an assembled symmetric MXene transparent supercapacitor, with a high transmittance of 73%, still surpasses the performance of previously reported graphene and single-walled carbon nanotube (SWCNT)-based transparent electrodes. The convenient manufacturing and superior electrochemical performance of inkjet-printed flexible and transparent MXene films widen the application horizon of this strategy for flexible energy storage devices.

Carbon nanotube (CNT)/n-Si heterojunction solar cells were fabricated based on solution processes. CNT film with high transparency of 90% and low sheet resistance of ∼115 Ω/sq was fabricated from commercially available CNT powder via dispersion-filtration process using poly(p-styrene-sulfonic acid) (PSS) as both dispersant and dopant. Heterojunction was then fabricated by attaching the CNT-PSS film onto an n-Si wafer. The CNT/n-Si solar cell showed an enhanced efficiency of 11.7% with the PSS-doping compared with the device without doping (7.7%). The device showed further improvements in efficiency to 14.1% with an antireflective coating layer of sulfonated polytetrafluoroethylene (Nafion) and stability to 1000 h in ambient air without additional protection. The solution-based strategies using polymeric acids for efficiency and stability enhancement will open new avenues for the low-cost CNT/Si heterojunction solar cells.

A thin film thickness meter was developed that is essential for thin film thickness management in the manufacturing process of flat panel displays such as touch panels and touch screens. The thickness measurement method of the meter is based on four-point probe method (Arther Uhlir in The Potentials of Infinite Systems of Sources and Numerical Solutions of Problems in Semiconductor Engineering 34:105-128, 1955; Valdes in Resistivity Measurements on Germaniumfor Transistors 42:420-427, 1954) and in the method, a thickness is determined by dividing the known electrical resistivity of a thin film material by the sheet resistance, and the thin film thickness measurement range is practically 1 nm–1 mm although the performance of the meter was confirmed in the range of 2.2 nm–22 μm. In order to conveniently measure the thickness of a thin film sample at a desired (to be measured) position, a probe station and a four-point probe were made. Place the four-point probe and the thin film sample at the probe station. When the four-point probe is brought into contact with the surface of the thin film sample using the upper and lower control knobs, the thickness measurement value is displayed on the meter, so the thickness of the thin film can be measured quickly and accurately. In addition, 5 types of samples such as Pd, Al, Au, Nb, and Cu were used to confirm the performance of the measuring device for the thin film thickness measurement function. For sample preparation, 5 types of samples were deposited on a silicon wafer with 75 mm in diameter, and the thickness was measured within 10 mm of the center of the sample, and the thickness of the cross-section was observed by SEM and TEM. As the result, the agreement for the thickness values between by the measurement results and SEM or TEM was confirmed in the range of 14 nm–1.6 μm.

Electrically conductive membranes are a promising avenue to reduce water treatment costs due to their ability to minimize the detrimental impact of fouling, to degrade contaminants, and to provide other additional benefits during filtration. Here, we demonstrate the facile and low-cost fabrication of electrically conductive membranes using laser-reduced graphene oxide (GO). In this method, GO is filtered onto a poly(ether sulfone) membrane support before being pyrolyzed via laser into a conductive film. Laser-reduced GO composite membranes are shown to be equally as permeable to water as the underlying membrane support and possess sheet resistances as low as 209 Ω/□. Application of the laser-reduced GO membranes is demonstrated through greater than 97% removal of a surrogate water contaminant, 25 μM methyl orange dye, with an 8 V applied potential. Furthermore, we show that laser-reduced GO membranes can be further tuned with the addition of p-phenylenediamine binding molecules to decrease the sheet resistance to 54 Ω/□.

Graphene is a promising flexible transparent electrode, and significant progress in graphene-based optoelectronic devices has been accomplished by reducing the sheet resistance and tuning the work function. Herein, phosphomolybdic acid (PMA) is proposed as a novel p-type chemical dopant for graphene, and the optical and electrical properties of graphene are investigated systematically. As a result, the monolayer graphene electrode with lower sheet resistance and work function are obtained while maintaining a high transmittance. The Raman spectrum proves the p-type doping effect of PMA on graphene, and the X-ray photoelectron spectroscopy results reveal the mechanism, which is that the electrons transfer from graphene to PMA through the Mo-O-C bond. Furthermore, using the PMA-doped graphene anode, organic and perovskite light-emitting diodes obtained the maximum efficiencies of 129.3 and 15.6 cd/A with an increase of 50.8 and 36.8% compared with the pristine counterparts, respectively. This work confirms that PMA is a potential p-type chemical dopant to achieve an ideal graphene electrode and demonstrates the feasibility of PMA-doped graphene in the practical application of next-generation displays and solid-state lighting.

Here, we report the enhanced optical and electrical properties of graphene oxide-silver nanoparticles (GO-AgNPs) nanocomposite due to thermal annealing in air at different temperatures (150, 250, and 350°C). Our findings show that the optical properties of the GO-AgNPs film strongly depend on the annealing temperature. With an increase in annealing temperature, the optical absorption band and photoluminescence (PL) band are monotonically shifted towards a longer wavelength with a slight increase in absorbance. Interestingly, annealing of the nanocomposite film at 350°C in the air results in the nitrogen-doping from air into GO lattice. Unlike the PL bands in the near-ultraviolet (UV) range in cases of GO-AgNPs annealed at 150 and 250°C, this film exhibits pronounced multiple PL bands in the visible range, which are attributed to optical transitions associated with the localized nitrogen defects incorporated from air under thermal annealing and charge transfer between AgNPs and carbon. Mechanisms of the observed optical properties are also discussed. Furthermore, thermal annealing of the film also affects its electrical properties. The sheet resistance of the film reduces with the increase of annealing temperature and its lowest value ~ 21 Ω/□ with transmittance ~ 82% at 550 nm is achieved at 350°C.

We proposed and fabricated an indium tin oxide (ITO)/Ag/Ga2O3 multilayer as transparent conductive electrode (TCE) for AlGaN-based ultraviolet light-emitting diode (UV LED). The effects of thickness dependence of Ga2O3 layer on the optical and electrical properties of the ITO/Ag/Ga2O3 multilayer are investigated. The ITO/Ag/Ga2O3(12nm/17.5nm/37.5nm) multilayer exhibits a small sheet resistance of $2.82~\Omega $ /sq and a good ohmic contact characteristic with a specific contact resistance of $2.61\times 10 ^{-3} \Omega \cdot $ cm2. The multilayer film has a good transmittance of 86.7% at 365 nm. Compared to reference UV LED with traditional ITO as TCE, the UV LED with ITO/Ag/ Ga2O3 multilayer as TCE shows an increase of 19.8% in light output power and a 0.34 V reduction in forward voltage at 120 mA.

In this communication, we propose a tunable radar absorber based on the combination of a graphene capacitor with a varactor-loaded active frequency-selective surface (FSS). The absorbing amplitude and frequency can be independently controlled by changing the effective sheet resistance of graphene and the capacitance of the varactor through different bias voltages, respectively. We fabricated the designed absorber and measured its tunable reflectivity. The measured results indicate that the absorber can tune its absorbing frequency ranging from 3.53 to 7.05 GHz under normal incidence when changing bias voltages applied to the varactors from 0.5 to 10 V. By further varying the graphene resistance through the bias voltage, the absorbing amplitude at each absorbing frequency can be dynamically modulated. In addition, it is found that the absorber achieves polarization-insensitive characteristics due to the symmetrical design of the active FSS. The physical mechanism of this absorber is discussed by providing the equivalent transmission-line (TL) model.

Herein we describe theoretical and experimental analysis of the source resistance (Rs) components in In0.7Ga0.3As/In0.52Al0.48As quantum-well (QW) high-electron-mobility transistors (HEMTs) on an InP substrate. First, we analytically modeled Rs using a three-layer formula, separately modeling the regions of the ohmic contact, the gate-to-source access, and the side-recessed regions. The resistances of the ohmic contact and access regions were analyzed in a distributed-network manner with two different transfer lengths, whereas the resistance associated with the side-recess region near the gate edge was modeled by using a lumped element. To verify the accuracy of the proposed Rs model, we fabricated two different types of transmission-line-method (TLM) test patterns as well as long-channel In0.7Ga0.3As/In0.52Al0.48As QW HEMTs, and compared their measured and modeled Rs. The modeled Rs was in excellent agreement with the measured Rs from the recessed TLM patterns and the long-channel HEMTs. Since the widths of the ohmic contact to the heavily doped In0.53Ga0.47As capping layer and the gate-to-source access region were typically much greater than corresponding transfer lengths ( $$L_{{{\text{T}}\_{\text{cap}}}}$$ and $$L_{{{\text{T}}\_{\text{barrier}}}}$$ ), those distributed networks could be simplified to a lumped-element based one-layer model, revealing that the tunneling resistance ( $$R_{{{\text{barrier}}}}$$ ) through the In0.52Al0.48As barrier should be carefully considered to minimize the Rs of InxGa1−xAs QW HEMTs together with S/D contact resistances and LGS.

The current article reviews the construction of thin films comprising carbon-based nanomaterials for application in electrical and electronic fields. Carbon-based materials such as carbon nanotubes, graphene, and fullerene are known to possess excellent electrical and electronic properties, which makes them desirable materials for the fabrication of micro- and nano-electromechanical devices. The fabrication process of thin films, including the deposition of several layers, removal of layers, solution processing methods, inkjet printing, micro-emulsion polymerization methods, deposition through filtration processes, spin coating, dip coating, pen lithography, vacuum-assisted flocculation, vacuum-assisted layer-by-layer assembly laser writing, etc., has been extensively reviewed. It is evident from the past findings that the fabricated thin films constituting carbon nanomaterials shows predominant alteration in electrical and electronic properties like sheet resistance, ionic transport, potential difference, conductivity, electro-rheological, transparency, trans-conductance, transmittance, bending stability, etc. In view of the referred properties, the developed materials find wide applications in charge-trap flash memories, flexible organic resistive memory devices, photovoltaic devices, flexible and transparent electronics, heat sinks in electronic materials, liquid crystal displays (LCDs), thin-film solar cells, flexible touch-screen panels, electronic papers, micro-batteries, electrochemical micro-capacitors, humidity sensors, optoelectronic devices, etc. We expect that the current review article will be a valuable asset for the researchers working in the field of carbon nanomaterials.

Owing to their eco-friendly substrate, cellulose-based transparent electrodes have attracted considerable attention from researchers. However, the fabrication methods for transparent electrodes were mostly developed by focusing on normal nonporous substrates such as polydimethylsiloxane or polyethylene terephthalate. Here, we demonstrate the fabrication of transparent conductive nitrocellulose (TCNC) by the filtration method with a 0.2 μm-pore nitrocellulose (NC) membrane and solvent evaporation process to fill in the pores. This method allows for simple and fast fabrication. To ensure good optical and electrical performances for diverse materials and compositions, single-wall carbon nanotubes, multiwall carbon nanotubes, reduced graphene oxide, and silver nanowires (AgNWs) are filtered onto the nitrocellulose. The filtrated conductive nitrocellulose membrane is transformed to nonporous TCNC by dimethylsulfoxide evaporation. The materials and surface morphology of TCNC, which is fabricated by these methods are analyzed by Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Moreover, TCNC fabricated by diverse materials is analyzed optically and electrically using the transmittance and sheet resistance, the current–voltage curve, and the mechanical properties. The highly conductive AgNW TCNC could be applied for touch-sensor devices and envelop-paper electronics, which may be operated by an embedded personal computer system.

Herein, we demonstrated for the first time the green fabrication of graphene by wet ball milling method which utilizes natural honey as exfoliation medium, further the 3D conductive networks (Graphene/Carbon nanotubes/PEDOT:PSS, G/CNT/PEDOT:PSS) were integrated into the biodegradable Starch/Chitosan/Poly vinyl alcohol (S/C/PVA) substrates. This electrode possesses an excellent optoelectronic performance (Rs = 43.2 Ω/sq., T = ca. 80% at 550 nm), and a very low Root Mean Square (RMS) roughness (approximately 1.38 nm). The sheet resistance of the films changed slightly after 1000 bending cycles and adhesion tests. The flexible green light OLED using G/CNT/PEDOT:PSS-S/C/PVA film as anode was successfully fabricated, the luminance of the device was 5701 cd/m2 at 15 V and the maximum current efficiency was 3.75 cd/A at 13 V. Moreover, this new type of OLED device degrades gradually within 10 min in 2 wt% lysozyme CH3COOH solution, which could be used to prepare the next generation of user-friendly, eco-friendly flexible wearable electronic devices.

Preparing high-quality graphene-like structures and materials in a consistent and environmentally friendly way is still elusive. Recent advances have revealed that laser irradiation of proper precursors presents great potential and versatility towards realizing high-quality growth of graphene-like materials at low cost. Here, we present a detailed study of the laser-assisted transformation of homogenized dried Corinthian raisins (Vitis vinifera L., var. Apyrena) to graphene-like material. This is a one-step process, as the transformation of the raw biomass material takes place at ambient conditions. Diffraction, Raman scattering and electron microscopy have revealed that the structure of the laser-irradiated product is found to differentiate significantly from that of Bernal stacked graphitic carbon. This is the first demonstration of a laser-assisted growth of turbostratic phase via the decomposition of an organic compound. XPS analysis show a very high C/O ratio, i.e. 19, after the decomposition of a raw biomass material. The combination of turbostratic structure and almost complete oxygen species removal results in an ultralow sheet resistance of 10 Ω·sq−1, confirming the successful modification of the raw material to a graphene-like structure with high sp2 hybridization degree. An additional merit of the current approach is that the process can induce both the growth of graphene-like structures on the irradiated target and in addition yields high-quality graphene-like powders. The latter have been used to prepare electrodes for symmetrical supercapacitors demonstrating superior performance compared to supercapacitors based on graphene prepared by other laser-assisted techniques.

Controlled cracking of two-dimensional layered materials (2DLMs) can dramatically alter their crystallographic orientation, energy band gap, sheet resistance, and phonon softening. Previously, grap...