Graphene transfer: key for applications

Abstract: Magnetic nanoparticles have become adaptable tools with multifaceted uses in differ-ent areas of science and technology. The review overviews recent developments in magnetic na-noparticle research, synthesis, and applications, emphasizing their promise in biomedicine, envi-ronmental remediation, and energy storage. The paper discusses the speciality of magnetic nano-particles in possessing a large surface area-to-volume ratio, super-paramagnetism, and biocom-patibility, rendering them extremely useful in targeted drug delivery, magnetic resonance imag-ing, and hyperthermia therapy. The latest advances in synthesis techniques, especially the transi-tion toward environmentally friendly biological methods, are reviewed. It also highlights the ob-stacles facing the production of Magnetic nanoparticles, including the need to standardize size distribution, increase targeting effectiveness and preserve prolonged stability in biological sys-tems. This review also focused on new applications in neuroscience, gene therapy, and combina-tion therapies, demonstrating that magnetic nanoparticles are multifunctional. Magnetic nanopar-ticles offer tremendous potential for use in medical applications such as therapeutic targeting and tracking, and environmental technologies, and their integration with other advanced technologies holds great promise for boosting their applications in personalized medicine and environmental technologies. However, progress has also come with challenges ranging from scaling up produc-tion to harmonizing evaluation processes and ensuring safety. Magnetic nanoparticles will play an increasingly important role in developing solutions to some of the world's most significant chal-lenges, from medicine to energy to environmental sustainability. They will only further facilitate a better, more technologically advanced future.

The future of waste-derived superabsorbent polymers (SAPs) is promising, with advances in synthesis techniques, materials science, and environmental applications driving their development. These polymers, made from waste sources such as domestic, agricultural, and industrial waste, are poised to address growing environmental challenges while supporting a circular economy. Technological innovations, including bio-inspired synthesis and greener polymerization methods, will improve production efficiency and expand the range of waste materials used. Future applications are expected to extend beyond agriculture and water purification into areas such as biomedical engineering, environmental remediation, and energy storage, where SAPs could play roles in tissue regeneration, pollution control, and CO2 capture. As sustainability becomes a priority, waste-derived SAPs will be integrated into circular bioeconomy systems, turning waste streams into valuable resources. Regulatory frameworks and market incentives will further promote their adoption, ensuring these materials contribute to global sustainability efforts. With these advancements, waste-derived SAPs will increasingly become a key component in tackling climate change, waste management, and resource scarcity.

Contamination of water resources, particularly from industrial discharges, agricultural runoff, or hospital wastewater, poses significant environmental and public health challenges. Traditional wastewater treatment methods often fail to effectively remove the diverse and persistent pollutants present in these sources, including emerging chemical compounds or biological agents. To address these challenges, metal–organic frameworks (MOFs) have emerged as multifunctional materials offering promising advancements in wastewater remediation. These materials can be applied directly as pollutant adsorbents or used for pathogen removal due to their antimicrobial activity. Additionally, MOFs play a crucial role in Advanced Oxidation Processes (AOPs) due to their catalytic activity. When incorporated into electro-Fenton, Fenton-like, or photocatalytic processes, MOFs enhance the generation of oxidant radicals, enabling efficient wastewater decontamination. This comprehensive review explores the potential of MOFs, focusing specifically on their design, synthesis, and application as multifunctional materials for the inactivation of pathogens and the removal of organic pollutants. Moreover, it examines their characteristics, recent advances in synthesis techniques, and the mechanisms underlying their removal efficiency. The findings presented underscore the transformative potential of MOFs in achieving clean and safer water, contributing to sustainable environmental management and public health protection.

Graphene films grown by the chemical vapor deposition (CVD) method suffer from contamination and damage during transfer. Herein, an innovative ice-enabled transfer method under an applied electric field and in the presence of Cu2O (or Cu2O-Electric-field Ice Transfer, abbreviated as CEIT) is developed. Ice serves as a pollution-free transfer medium while water molecules under the electric field fully wet the graphene surface for a bolstered adhesion force between the ice and graphene. Cu2O is used to reduce the adhesion force between graphene and copper. The combined methodology in CEIT ensures complete separation and clean transfer of graphene, resulting in successfully transferred graphene to various substrates, including polydimethylsiloxane (PDMS), Teflon, and C4F8 without pollution. The graphene obtained via CEIT is utilized to fabricate field-effect transistors with electrical performances comparable to that of intrinsic graphene characterized by small Dirac points and high carrier mobility. The carrier mobility of the transferred graphene reaches 9090 cm2V-1s-1, demonstrating a superior carrier mobility over that from other dry transfer methods. In a nutshell, the proposed clean and efficient transfer method holds great potential for future applications of graphene.

The exceptional charge-transport, mechanical, and barrier properties of graphene are well known. High-quality films of single-layer graphene produced over large areas, however, are extremely expensive. The high cost of graphene precludes its use in industries-such as transparent electrodes and flexible packaging-that might take full advantage of its properties. This minireview presents several strategies for the transfer of graphene from the substrates used for growth to substrates used for the final application. Each strategy shares the characteristic of being non-destructive: that is, the growth substrate remains reusable for further synthesis of new graphene. These processes have the potential to lower significantly the costs of manufacturing graphene, to increase production yields, and to minimize environmental impact. This article is divided into sections on (i) the synthesis of high-quality single-layer graphene and (ii) its non-destructive transfer to a host substrate. Section (ii) is further divided according to the substrate from which graphene is transferred: single-crystalline wafers or flexible copper foils. We also comment, wherever possible, on defects produced as a result of the transfer, and potential strategies to mitigate these defects. We conclude that several methods for the green synthesis and transfer of graphene have several of the right characteristics to be useful in industrial scale production.

The preparation of graphene with high quality serves as a prerequisite for its usage. Traditional methods of graphene production, represented by liquid-phase exfoliation and chemical vapor depositi...

Paraffin wax assisted chemical vapor deposited graphene transfer method

Several kinds of chemical vapor deposition (CVD) methods have been extensively used in the semiconductor industries for bulk crystal growth, thin film deposition, and nanomaterials synthesis. In this article, we focus on the microwave-excited surface wave plasma CVD (MW-SWP CVD) method for growth of graphene and related materials. The MW-SWP CVD system consisting of waveguide, slot antenna, and dielectric windows is significant for generating high density plasma with low electron temperature, enabling low temperature growth of materials without damaging the surface of base substrates. The synthesis of graphene and hexagonal boron nitride (hBN) films has been achieved on metals, semiconductors, insulators, and dielectric substrates for application in photovoltaics, sensors, batteries, supercapacitors, fuel cells, and various other electronic devices. The details of the synthesis process for graphene films, vertically-oriented graphene, doped-graphene, and hBN films by the MW-SWP CVD method are summarized to understand the growth mechanism, which will enable further development of the plasma CVD process for material synthesis at a low temperature for industrial applications.

Since the first isolation of graphene in 2004 by mechanical exfoliation from graphite, many people have tried to synthesize large-scale graphene using various chemical methods. In particular, there has been a great number of advances in the synthesis of graphene using chemical vapor deposition (CVD) on metal substrates such as Ni and Cu. Recently, a method to synthesize ultra-large-scale (∼30 inch) graphene films using roll-to-roll transfer and chemical doping processes was developed that shows excellent electrical and physical properties suitable for practical applications on a large scale. Considering the outstanding scalability/processibility of roll-to-roll and CVD methods as well as the extraordinary flexibility/conductivity of graphene films, we expect that transparent graphene electrodes can replace indium tin oxide in the near future.

We propose a graphene transfer method based on chemical vapor deposited (CVD) graphene grown on copper foils. This transfer method utilizes a combination of a silicone elastomer (PDMS) and different intermediate polymer layers depending on the process requirements. We use polystyrene and polystyrene/photoresist intermediary layers for dry and wet graphene release. PMMA intermediary layer is applied for bubbling-assisted graphene transfer. The elastomer layer serves as an excellent solid support for electrochemical graphene delamination. Graphene-based field effect transistors (GFETs) were fabricated and characterized using this process. Raman spectroscopy was used in order to verify a successful transfer.

The synthesis of uniform low-defect graphene on a catalytic metal substrate is getting closer to the industrial level. However, its practical application is still challenging due to the lack of an appropriate method for its scalable damage-free transfer to a device substrate. Here, an efficient approach for a defect-free, etchant-free, wrinkle-free, and large-area graphene transfer is demonstrated by exploiting a multifunctional viscoelastic polymer gel as a simultaneous shock-free adhesive and dopant layer. Initially, an amine-rich polymer solution in its liquid form allows for conformal coating on a graphene layer grown on a Cu substrate. The subsequent thermally cured soft gel enables the shock-free and wrinkle-free direct mechanical exfoliation of graphene from a substrate due to its strong charge-transfer interaction with graphene and excellent shock absorption. The adhesive gel with a high optical transparency works as an electron doping layer toward graphene, which exhibits significantly reduced sheet resistances without optical transmittance loss. Lastly, the transferred graphene layer shows high mechanical and chemical stabilities under the repeated bending test and exposure to various solvents. This gel-assisted mechanical transfer method can be a solution to connect the missing part between large-scale graphene synthesis and next-generation electronics and optoelectronic applications.

Despite the various techniques developed for the transfer of large area graphene grown by chemical vapor deposition (CVD), the conventional polymethylmethacrylate (PMMA) transferring technique has been widely applied in laboratories due to its convenience and economical cost. However, the complete removal of PMMA on graphene surface has become a troublesome, and the PMMA residue could degrade the properties of graphene significantly. We report here a facile water assisted technique to directly peel off the PMMA layer over centimeter-sized CVD graphene film for the first time. No organic solvents are involved in the whole transfer process. The transferred graphene film is clean and intact over large area because of the cooperative effect of the capillary force and the van der Waals force which facilitates the conformal contact between graphene film and the substrate. Various types of graphene samples (i.e. monolayer, multilayer, and incomplete domains) can be easily transferred to diverse substrates including silicon wafer, sapphire, and quartz with good integrity. The transferred graphene film is of high cleanliness, and the graphene transistors show higher carrier mobility and lower level of p-type doping comparing to the conventional wet transfer technique.

Facile transfer of monolayer graphene onto polyethylene via van der Waals interactions to prepare layered composite membranes

In the current work we will present the transfer of graphene pixels and arrays. The process we used to accomplish the transfer was the Laser Induced Transfer technique. We will exhibit the advantages of the certain technique, the resolution of the transferred pixels and the characterization of the samples. Also, we will demonstrate the transfer of graphene arrays on both flexible polymeric and rigid substrates. The transfer of the graphene pixels was accomplished for resolution from 40 μm to 15 μm, whereas the digital manipulation of the transfer enables the deposition of arrays with dimension up to 1 mm2. Furthermore, in this work we will present the fabrication of a flexible capacitance touch sensor. The device is composed by LIFT transfer bottom electrodes and top electrodes and between them we deposit a insulating layer with the assistance of a spin-coater. For bottom electrodes we used silver nanoparticles ink, which was LIFT transferred and laser sintered in order to be conductive and form two pads with a line to connect them. The top electrode is a transferred graphene array with dimension at 1 mm2 and the insulating layer we used is an in-house fabricated PDMS, which was deposited on the half of the bottom electrodes. The quality and quantity of graphene layers were measured and characterized with Scanning Electron Microscopy and micro-Raman spectroscopy. Electrical measurements were conducted on the same samples in order to receive the sheet resistance and the capacitance values. The capacitance measurements were conducted at the top electrode of the flexible touch sensor. Finally, we will introduce the next step in the demonstration of the touch sensor, which is the application of tensile or compressive stress on the flexible touch sensor, which will result in accumulation of different capacitance.

The single-layer graphene film, when incorporated with molecular-sized pores, is predicted to be the ultimate membrane. However, the major bottlenecks have been the crack-free transfer of large-area graphene on a porous support, and the incorporation of molecular-sized nanopores. Herein, we report a nanoporous-carbon-assisted transfer technique, yielding a relatively large area (1 mm2), crack-free, suspended graphene film. Gas-sieving (H2/CH4 selectivity up to 25) is observed from the intrinsic defects generated during the chemical-vapor deposition of graphene. Despite the ultralow porosity of 0.025%, an attractive H2 permeance (up to 4.1 × 10−7 mol m−2 s−1 Pa−1) is observed. Finally, we report ozone functionalization-based etching and pore-modification chemistry to etch hydrogen-selective pores, and to shrink the pore-size, improving H2 permeance (up to 300%) and H2/CH4 selectivity (up to 150%). Overall, the scalable transfer, etching, and functionalization methods developed herein are expected to bring nanoporous graphene membranes a step closer to reality.