Composite-based piezoelectric devices are extensively studied to develop sustainable power supply and selfpowered devices owing to their excellent mechanical durability and output performance. In this study, we design a leadfree piezoelectric nanocomposite utilizing (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) nanomaterials for realizing highly flexible energy harvesters. To improve the output performance of the devices, we incorporate porous BCTZ nanowires (NWs) into the nanoparticle (NP)-based piezoelectric nanocomposite. BCTZ NPs and NWs are synthesized through the solidstate reaction and sol-gel-based electrospinning, respectively; subsequently, they are dispersed inside a polyimide matrix. The output performance of the energy harvesters is measured using an optimized measurement system during repetitive mechanical deformation by varying the composition of the NPs and NWs. A nanocomposite-based energy harvester with 4:1 weight ratio generates the maximum open-circuit voltage and short-circuit current of 0.83 V and 0.28 A, respectively. In this study, self-powered devices are constructed with enhanced output performance by using piezoelectric energy harvesting for application in flexible and wearable devices.

이온교환막은 전기막 공정의 성능을 결정하는 핵심 구성 요소이다. 본 총설에서는 다양한 전기막 공정에 적용되 는 이온교환막의 성능을 탄소계 및 금속계 나노물질을 이용한 개질을 통해 향상시킨 최신 연구 동향을 살펴보았다. 나노물질 들은 다양한 방법을 통해 이온교환막에 도입될 수 있다. 특히 탄소계 나노물질은 화학적 개질을 통해 추가적인 기능기를 도 입함으로써 고분자 사슬과의 상호작용을 강화할 수 있다. 이를 통해 이온교환막의 이온전도도를 개선시킬 수 있을 뿐만 아니 라 적층 구조를 통한 체거름 현상으로 이온 선택 투과성을 향상시킬 수 있다. 한편, 금속계 나노물질은 적층 구조 혹은 다공 성 구조를 갖는 특성을 이용하여 이온교환막 내에서 목적 이온과 배제 이온 간의 수화 반경 차이를 이용한 체거름 특성을 통 해 이온 선택 투과성을 향상시킬 수 있다. 또한, 사용한 바인더의 특성에 따라서는 나노물질-바인더 간의 상호작용을 통해 이 온전도도도 향상시킬 수 있다. 본 총설로부터 탄소계 및 금속계 나노물질을 이용하여 이온교환막의 특성을 효과적으로 조절 할 수 있으며, 따라서 이에 관한 연구가 전기막 공정의 성능을 크게 향상시키기 위해 중요함을 확인할 수 있다.

Phytohormones (plant hormones) are a class of small-molecule organic compounds synthesized de novo in plants. Although phytohormones are present in trace amounts, they play a key role in regulating plant growth and development, and in response to external stresses. Therefore, the analysis and monitoring of phytohormones have become an important research topic in precision agriculture. Among the various detection methods, electrochemical analysis is favored because of its simplicity, rapidity, high sensitivity, and in-situ monitoring. Graphene and graphene-like carbon materials have abundant sources, exhibiting large specific surface area, and excellent physicochemical properties. Thus, they have been widely used in the preparation of electrochemical biosensors for phytohormone detection. In this paper, the research advances of electrochemical sensors based on graphene and graphene-like carbon materials for phytohormone detection have been reviewed. The properties of graphene and graphene-like carbon materials are first introduced. Then, the research advances of electrochemical biosensors (including conventional electrochemical sensors, photoelectrochemical sensors, and electrochemiluminescence sensors) based on graphene and graphene-like carbon materials for phytohormone detection is summarized, with emphasis on their sensing strategies and the roles of graphene and graphene-like carbon materials in them. Finally, the development of electrochemical sensors based on graphene and graphene-like carbon materials for phytohormone detection is prospected.

In this study, using deep learning, super-resolution images of transmission electron microscope (TEM) images were generated for nanomaterial analysis. 1169 paired images with 256  256 pixels (high resolution: HR) from TEM measurements and 32  32 pixels (low resolution: LR) produced using the python module openCV were trained with deep learning models. The TEM images were related to DyVO4 nanomaterials synthesized by hydrothermal methods. Mean-absolute-error (MAE), peak-signal-to-noise-ratio (PSNR), and structural similarity (SSIM) were used as metrics to evaluate the performance of the models. First, a super-resolution image (SR) was obtained using the traditional interpolation method used in computer vision. In the SR image at low magnification, the shape of the nanomaterial improved. However, the SR images at medium and high magnification failed to show the characteristics of the lattice of the nanomaterials. Second, to obtain a SR image, the deep learning model includes a residual network which reduces the loss of spatial information in the convolutional process of obtaining a feature map. In the process of optimizing the deep learning model, it was confirmed that the performance of the model improved as the number of data increased. In addition, by optimizing the deep learning model using the loss function, including MAE and SSIM at the same time, improved results of the nanomaterial lattice in SR images were achieved at medium and high magnifications. The final proposed deep learning model used four residual blocks to obtain the characteristic map of the low-resolution image, and the super-resolution image was completed using Upsampling2D and the residual block three times.

The implanted electronic devices require a stable, continuous, and long-lasting energy source to function correctly. These devices are powered by alkaline batteries and lithium ions. When used in implantable or wearable devices, these batteries can pose a threat to human health and the environment. Because of these factors, implantable and wearable devices using enzyme biofuel cells (EBFCs) are receiving a lot of attention. These EBFCs use human physiological fluid to provide longterm control for these devices. Carbon nanomaterials have successfully been demonstrated in enzymatic biofuel cells to improve applications by increasing current and power density; they have the potential to enhance EBFC efficiency. This review summarizes the fundamental process of EBFC compounds based on carbon nanomaterials before delving into the most recent advancements that have been tested and used as implantable and wearable self-power sources.

Nanomaterials (NMs) are gradually becoming pervasive in the modern world, entering every application for improving the quality of life. Multifaceted uses of NMs in curing diseases, biomedical instrumentation, bioimaging, drugs, and gene delivery, display devices, nanosensors, and biomarkers in several fields ranging from agriculture to industries, healthcare, and environment, have been well recognized. Carbon-based nanomaterials (CNMs) constitute a major type of NMs with broad-spectrum applications including their uses in agriculture. These are synthesized in large quantities via synthetic and biological approaches. Biological approaches are gaining appreciation and momentum, owing to the advantages associated with them, major being their environment friendly or ‘Green’ nature. This topical review focuses on the preparation of CNMs using natural resources, i.e., using the Green Nanotechnology. The up-to-date compilation presented here includes most of the popular green technological methods of producing the CNMs and their immediate uses as anticancer agents, in bio-labelling, as biosensors, in bio-remediation, in cell imaging, in fluorescent inks, and fluorescent dyes, as plant growth inducing agents, in nano-probes, in light-emitting devices and other applications. It is intended to update the reader with the state-of-the-art knowledge about the green technological methods for synthesizing CNMs, their uses, current trends, challenges, and future outlook on the topic.

Oil spills into ocean or coastal waters can result in significant damage to the environment via pollution of aquatic ecosystems. Absorbents based on reduced graphene oxide (rGO) foams have the capacity to remove minor or major oil spills. However, conventional chemical synthesis of rGO often uses petrochemical precursors, potentially harmful chemicals, and requires special processing conditions that are expensive to maintain. In this work, an alternative cost-effective and environmentally friendly approach suitable for large-scale production of high-quality rGO directly from used cooking sunflower oil is discussed. Thus, produced flaky graphene structures are effective in absorbing used commercial sunflower oil and engine oil, via monolayer physisorption in the case of used sunflower and engine oils facilitated by van der Waals forces, π–π stacking and hydrophobic interactions, π-cation ( H+) stacking and radical scavenging activities. From adsorption kinetic models, first-order kinetics provides a better fit for used sunflower oil adsorption (R2 = 0.9919) and second-order kinetics provides a better fit for engine oil adsorption (R2 = 0.9823). From intra-particle diffusion model, R2 for USO is 0.9788 and EO is 0.9851, which indicates that both used sunflower and engine oils adsorption processes follow an intra-particle diffusion mechanism. This study confirms that waste-derived rGO could be used for environmental remediation.

산업화와 기후 변화는 깨끗한 식수에 대한 수요 증가를 초래하였다. 막분리공정을 이용한 해수담수화는 물의 수요에 대한 요구를 채울 수 있는 경제적으로 실현 가능한 대안 중 하나이다. 막분리공정에서 2차원 재료들은 기존 역삼투분리막 (reverse osmosis membrane) 기반의 폴리아마이드 박막복합막(TFC-PA)과 비교하였을 때 막의 강도를 높여주고 투수성을 용이하게 하며 높은 염제거율 및 높은 선속률과 선택성을 보여준다. 이 리뷰 논문에서는 재료, 합성, 특징, 해수담수화 과정을 기반으로 다양한 2차원 재료로 구성된 복합막들을 소개하고 있다.

Highly active, stable and low-cost noble metal-free electrocatalysts are essential for production of hydrogen. However, preparation of such catalysts is still highly challenging so far. In this work, the Mo2C– carbon nanomaterials have been prepared by controlled thermal technique. By controlling concentration of the reactants in the experimental condition, the Mo2C– carbon nanomaterials have been fabricated, which leads to decreases in contact resistance b/w Mo2C– carbon nanomaterials and graphitic carbon atoms. As a result, the Mo2C– carbon nanomaterial electrode shows remarkable activity for hydrogen evolution reactions with a small onset overpotential of 95 mV, a Tafel slope of 62 mV dec−1, an high exchange current density of 0.32 mA cm−2, good stability during long-term 1000 cycles and exhibits long-term durability for several days. This study opens a new method for the preparation of highly active non-noble electrode for production of hydrogen from water splitting.

One- and two-dimensional carbon nanomaterials were tested as adsorbents for the elimination of two anionic dyes, reactive red 2 and methyl orange, and the cationic dye methylene blue from aqueous solutions under the same conditions. Carbon nanomaterials performed well in the removal of dyes. Surface oxygenated groups in the nanomaterials improved the cationic dyes’ adsorption, but not the adsorption of the anionic dye. The interactions between nanomaterials and dyes were verified by infrared and Raman spectroscopy. The pseudo-second order kinetic model was better fitted to the kinetic experimental data than the Elovich and pseudo-first order models. The equilibrium adsorption data were best fitted by the Langmuir model. The dimensions and morphology of the carbon nanomaterials play an important role in the adsorption of the three dyes. The main mechanism of adsorption of anionic dyes is by the interactions of the aromatic rings of the dye structures and π delocalized electrons on carbon nanostructures; the adsorption of cationic dye is mainly due to electrostatic interactions.

In the present study, we develop a conductive copper/carbon nanomaterial additive and investigate the effects of the morphologies of the carbon nanomaterials on the conductivities of composites containing the additive. The conductive additive is prepared by mechanically milling copper powder with carbon nanomaterials, namely, multi-walled carbon nanotubes (MWCNTs) and/or few-layer graphene (FLG). During the milling process, the carbon nanomaterials are partially embedded in the surfaces of the copper powder, such that electrically conductive pathways are formed when the powder is used in an epoxy-based composite. The conductivities of the composites increase with the volume of the carbon nanomaterial. For a constant volume of carbon nanomaterial, the FLG is observed to provide more conducting pathways than the MWCNTs, although the optimum conductivity is obtained when a mixture of FLG and MWCNTs is used.

Recent developments in the field of energy harvesting technology that convert ambient energy resources into electricity enable the use of self-powered energy systems in wearable and portable electronic devices without the need for additional external power sources. In particular, piezoelectric-effect-based flexible energy harvesters have drawn much attention because they can guarantee power generation from ubiquitous mechanical and vibrational movements. In response to demand for sustainable, permanent, and remote use of real-life personal electronics, many research groups have investigated flexible piezoelectric energy harvesters (f-PEHs) that employ nanoscaled piezoelectric materials such as nanowires, nanoparticles, nanofibers, and nanotubes. In those attempts, they have proven the feasibility of energy harvesting from tiny periodic mechanical deformations and energy utilization of f-PEH in commercial electronic devices. This review paper provides a brief overview of f-PEH devices based on piezoelectric nanomaterials and summarizes the development history, output performance, and applications.

Colloidally synthesized luminescent nanocrystals (NCs) have attracted tremendous attention due to their unique nanoscale optical and electronic properties. The emission properties of these NCs can be precisely tuned by controlling their size, shape, and composition as well as by introducing appropriate dopant impurities. Nowadays, these NCs are actively utilized for various applications such as optoelectronic devices including light emitting diodes (LEDs), lasers, and solar cells, and bio-medical applications such as imaging agents and bio-sensors. In this review, we classify luminescent nanomaterials into quantum dots (QDs), upconversion nanoparticles (UCNPs), and perovskite NCs and present their intrinsic emission mechanism. Furthermore, the recently emerging issues of efficiency, toxicity, and durability in these materials are discussed for better understanding of industry demands. As well, the future outlook will be offered for researchers to guide the direction of future research.

Thin-film nanocomposite (TFN) reverse osmosis (RO) membranes have drawn keen attention to overcome the limitations in polymeric desalination membranes. However, preparation of TFN-RO membranes using conventional protocol involves problems such as a waste of expensive nanomaterials and inaccurate control of loading amount. In this work, we suggest a new protocol of TFN-RO membranes through pre-adsorption of carbon nanotubes (CNTs) on the support layer using spray coating. SEM images of spray coated supports showed well-dispersed adsorption of CNTs compared with those using conventional method. RO performances of TFN membranes using spray coating were comparable to conventionally prepared membranes. Thus, this new protocol is useful to prepare TFN membranes in terms of cost-efficiency.

Owing to high energy efficiency and superior efficacy, membrane-based desalination processes have gained widespread implementation in a wide variety of water treatment applications. Tremendous research efforts on new membrane materials have been made to improve the separation performance of the state-of-the-art thin-film composite (TFC) membranes, particularly polyamide TFC membranes, hoping to overcome the permeability-selectivity trade-off relations. Currently, many nanomaterials such as zeolites, metal-organic frameworks (MOFs), graphene oxide (GO), and carbon nanotubes (CNTs) have been explored to enhance the separation performance of existing polymeric membranes, but it has been argued that the positive transformation of nanomaterials-embedded TFC membranes hold promising potential to realize the sustainable development of current desalination membranes. Here we have tried to discuss some misconceptions and challenging items delaying industrial-scale implementation of nanomaterialsembedded desalination membranes.

결정성 탄소물질은 결합의 형태에 따라 carbyne (sp1, 1D 구조), graphite (sp2+π, 2D), diamond (sp3, 3D) 구조 로 나뉜다. 특히 sp2 결합에 기반한 나노물질은 fullerene (0D), 탄소나노튜브 (1D or quasi-2D), 그래핀 (2D) 으로 나뉜 다. 탄소나노튜브와 그래핀은 물리적으로 여러 가지 뛰어난 특성이 있어 구조재나 광전자 재료, 멤브레인 등 다양한 분 야에 응용가치가 높다. 하지만 이들 나노재료는 강하게 응집되는 성질이 있어 용액에 분산할 필요가 있다. 특히 이는 용 액 상에서 박리, 안정화의 과정을 거쳐야 안정적으로 분산된 상태를 유지할 수 있다. 본 고에서는 탄노나노튜브나 그래 핀이 용매에서 박리되어

Silver nanomaterials have been intensively applied in consumer products of diverse industrial sectors because of their strong biocidal properties and reported to be hazardous to aquatic organisms once released in the environment. Nanomaterials including sliver, are known to be different in toxicity according to their physicochemical characteristics such as size, shape, length etc. However studies comparing toxicity among silver nanomaterials with different physicochemical characteristics are very limited. Here, toxicities of silver nanomaterials with different size (50, 100, 150 nm), length (10, 20 μm), shape (wire, sphere), and coating material (polyvinylpyrrolidone, citrate) using OECD test guidelines were evaluated in aquatic species (zebrafish, daphnia, algae) and compared. On a size property, the smaller of silver nanomaterials, the more toxic to tested organisms. Sphered type of silver nanomaterials was less toxic to organisms than wired type, and shorter nanowires were less toxic than longer ones. Meanwhile the toxic effects of materials coated on silver nanomaterials were slightly different in each tested species, but not statistically significant. To the best of our knowledge, it is first investigation to evaluate and compare ecotoxicity of silver nanomaterials having different physicochemical characteristics using same test species and test guidelines. This study can provide valuable information for human and environmental risk assessment of silver nanomaterials and guide material manufacturers to synthesize silver nanomaterials more safely to human and environment.