Desirable Structure Research Articles

Synthesis and characterization of Co3O4 nanoneedle structures for enhancing the supercapacitive performance

The present study focuses on the synthesis of Co3O4 nanoneedles utilizing a deep eutectic solvent (DES) comprising choline chloride and urea, renowned for its environmentally advantageous characteristics. The deposition time was modified to achieve the desired Co3O4 nanoneedle structure, as indicated by several analyses including structural, vibrational, morphological, elemental, surface area, and pore distribution examinations. Following the initial characterization, other electrochemical storage characterizations were conducted. Experimentally it has been found that the optimum Co3O4 samples yielded 1-D mesoporous nanoneedle structure with the features like (i) a substantial presence of oxygen vacancies, (ii) a relatively greater surface area, and (iii) a suitable pore size. As a result, of which it shows significant specific capacitance of 880 Fg−1 when subjected to a current density of 0.66 Ag−1 in a 2 M KOH aqueous electrolyte. Additionally, it displayed excellent retention of 118% at 60 mVs−1 scan rate after undergoing 5000 cycles. Moreover, a symmetric supercapacitor with a liquid electrolyte was constructed using identical nanoneedle Co3O4 materials as both the cathode and anode. The experimental results demonstrated a specific capacitance of 98.39 Fg−1 at a current density of 0.66 Ag−1. Furthermore, the device exhibited an energy density of 18 Whkg−1 along with a power density of 200 Wkg−1, demonstrating exceptional cycling stability of 94% over a span of 5,000 cycles.

Generating optimal designs with user‐specified pure replication structure

AbstractOver recent decades, optimal experimental design has surged in popularity due to affordable computing and efficient algorithms. However, some researchers highlight that this focus has often side‐lined the importance of including pure experimental replication in designs, as many optimality criteria do not inherently suggest designs with replicates. In this study, we introduce an approach that allows the designer to input a desired replication structure into the optimal design search. We list all potential replication structures, indicate the corresponding budget for pure‐error (PE) and lack‐of‐fit (LOF) degrees‐of‐freedom, and use particle swarm optimization to search for the optimal design in each scenario. We demonstrate our approach on various unexplored ‐optimal design scenarios and several scenarios recently discussed in literature. Our findings reveal the existence of highly‐efficient ‐optimal designs with unique replication structures, offering designers informed choices on allocating a limited budget for PE and LOF degrees‐of‐freedom. This method is versatile and compatible with other optimizers, such as the coordinate exchange.

Soil Substrate Characteristics for Planting Hole Greening Technology for High, Steep, Rocky Slope Vegetation in Semi-Arid Areas

Soil substrate plays a central role in the vegetation restoration of high and steep slopes, especially in semi-arid regions. This study aims to develop an optimal soil substrate that can provide a favorable environment for the vegetation growth of the high and steep rocky slopes in semi-arid areas. Within the framework of planting hole greening technology, we developed a synthetic substrate comprising base soil, peat, water-retaining and agglomerating agents, biochar, and controlled-release compound fertilizer. We conducted pot experiments to assess the impact of compound additions on soil properties and Parthenocissus himalayana growth. Field tests on exposed, high, and steep rocky slopes in a semi-arid region validated the optimal ratio of substrate components. The results showed that the base soil-to-peat ratio significantly influenced soil density, moisture, pH, organic matter, nitrogen content, and vegetation growth (Ps < 0.05). The controlled-release compound fertilizer significantly affected soil electrical conductivity and alkali-hydrolyzable nitrogen content (Ps < 0.05). Meanwhile, the water-retaining agent, biochar, and agglomerating agent had inconsequential effects on soil characteristics and plant growth. The optimal substrate composition included a 7:3 ratio of base soil to peat, 1.5 g/L of water retainer, 10 mg/L of agglomerating agent, 5 g/L of biochar, and 5 g/L of controlled-release compound fertilizer. The field verification showed that the developed optimal substrate possessed desirable pore structure, moisture, and nutrients, resulting in excellent growth of Parthenocissus himalayana. This optimal soil substrate could be suitable for establishing vegetation on high, steep, rocky slopes in semi-arid areas using planting hole greening technology.

Advances in Nanoarchitectonics: A Review of "Static" and "Dynamic" Particle Assembly Methods.

Particle assembly is a promising technique to create functional materials and devices from nanoscale building blocks. However, the control of particle arrangement and orientation is challenging and requires careful design of the assembly methods and conditions. In this study, the static and dynamic methods of particle assembly are reviewed, focusing on their applications in biomaterial sciences. Static methods rely on the equilibrium interactions between particles and substrates, such as electrostatic, magnetic, or capillary forces. Dynamic methods can be associated with the application of external stimuli, such as electric fields, magnetic fields, light, or sound, to manipulate the particles in a non-equilibrium state. This study discusses the advantages and limitations of such methods as well as nanoarchitectonic principles that guide the formation of desired structures and functions. It also highlights some examples of biomaterials and devices that have been fabricated by particle assembly, such as biosensors, drug delivery systems, tissue engineering scaffolds, and artificial organs. It concludes by outlining the future challenges and opportunities of particle assembly for biomaterial sciences. This review stands as a crucial guide for scholars and professionals in the field, fostering further investigation and innovation. It also highlights the necessity for continuous research to refine these methodologies and devise more efficient techniques for nanomaterial synthesis. The potential ramifications on healthcare and technology are substantial, with implications for drug delivery systems, diagnostic tools, disease treatments, energy storage, environmental science, and electronics.

Synergistic chemo-photothermal therapy using gold nanorods supported on thiol-functionalized mesoporous silica for lung cancer treatment

Cancer therapy necessitates the development of novel and effective treatment modalities to combat the complexity of this disease. In this project, we propose a synergistic approach by combining chemo-photothermal treatment using gold nanorods (AuNRs) supported on thiol-functionalized mesoporous silica, offering a promising solution for enhanced lung cancer therapy. To begin, mesoporous MCM-41 was synthesized using a surfactant-templated sol–gel method, chosen for its desirable porous structure, excellent biocompatibility, and non-toxic properties. Further, thiol-functionalized MCM-41 was achieved through a simple grafting process, enabling the subsequent synthesis of AuNRs supported on thiol-functionalized MCM-41 (AuNR@S-MCM-41) via a gold-thiol interaction. The nanocomposite was then loaded with the anticancer drug doxorubicin (DOX), resulting in AuNR@S-MCM-41-DOX. Remarkably, the nanocomposite exhibited pH/NIR dual-responsive drug release behaviors, facilitating targeted drug delivery. In addition, it demonstrated exceptional biocompatibility and efficient internalization into A549 lung cancer cells. Notably, the combined photothermal-chemo therapy by AuNR@S-MCM-41-DOX exhibited superior efficacy in killing cancer cells compared to single chemo- or photothermal therapies. This study showcases the potential of the AuNR@S-MCM-41-DOX nanocomposite as a promising candidate for combined chemo-photothermal therapy in lung cancer treatment. The innovative integration of gold nanorods, thiol-functionalized mesoporous silica, and pH/NIR dual-responsive drug release provides a comprehensive and effective therapeutic approach for improved outcomes in lung cancer therapy. Future advancements based on this strategy hold promise for addressing the challenges posed by cancer and transforming patient care.

Dual-salt strategy tuning the solvation structure to achieve high cycling stability for FeS2 cathodes

Pyrite FeS2, as a promising conversion-type cathode material, faces rapid capacity degradation due to challenges such as polysulfide shuttle and massive volume changes. Herein, a localized high-concentration electrolyte (LHCE) based on dual-salt lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesulphonyl)imide (LiTFSI) is designed to address the challenges. By the dual-salt strategy, we tailor a more desirable solvation structure than that in the single-salt system. Specifically, the solvation structure involving FSI− and TFSI− enables milder electrolyte decomposition, which reduces initial capacity loss. Meanwhile, it facilitates the formation of a stable and flexible cathode/electrolyte interphase (CEI), effectively mitigating side effects and accommodating volume changes. Consequently, the micro-sized FeS2 realizes a capacity of 641 mAh g−1 after 600 cycles with a retention rate of 90%, significantly improving the cycling stability of the FeS2 cathode. This work underscores the pivotal role of solvation structure in modulating electrochemical performances and provides a simple and effective electrolyte design concept for conversion-type cathodes.

Denoising diffusion probabilistic models for generation of realistic fully-annotated microscopy image datasets.

Recent advances in computer vision have led to significant progress in the generation of realistic image data, with denoising diffusion probabilistic models proving to be a particularly effective method. In this study, we demonstrate that diffusion models can effectively generate fully-annotated microscopy image data sets through an unsupervised and intuitive approach, using rough sketches of desired structures as the starting point. The proposed pipeline helps to reduce the reliance on manual annotations when training deep learning-based segmentation approaches and enables the segmentation of diverse datasets without the need for human annotations. We demonstrate that segmentation models trained with a small set of synthetic image data reach accuracy levels comparable to those of generalist models trained with a large and diverse collection of manually annotated image data, thereby offering a streamlined and specialized application of segmentation models.

Emerging Two-Dimensional Carbonaceous Materials for Electrocatalytic Energy Conversions: Rational Design of Active Structures through High-Temperature Chemistry.

Electrochemical energy conversion and storage technologies involving controlled catalysis provide a sustainable way to handle the intermittency of renewable energy sources, as well as to produce green chemicals/fuels in an ecofriendly manner. Core to such technology is the development of efficient electrocatalysts with high activity, selectivity, long-term stability, and low costs. Here, two-dimensional (2D) carbonaceous materials have emerged as promising contenders for advancing the chemistry in electrocatalysis. We review the emerging 2D carbonaceous materials for electrocatalysis, focusing primarily on the fine engineering of active structures through thermal condensation, where the design, fabrication, and mechanism investigations over different types of active moieties are summarized. Interestingly, all the recipes creating two-dimensionality on the carbon products also give specific electrocatalytic functionality, where the special mechanisms favoring 2D growth and their consequences on materials functionality are analyzed. Particularly, the structure-activity relationship between specific heteroatoms/defects and catalytic performance within 2D metal-free electrocatalysts is highlighted. Further, major challenges and opportunities for the practical implementation of 2D carbonaceous materials in electrocatalysis are summarized with the purpose to give future material design guidelines for attaining desirable catalytic structures.

New construction strategies of carbon‐based composites for flexible electromagnetic interference shielding films

AbstractDue to the quick growth of portable/wearable devices and electronics, the development of high efficiency flexible electromagnetic interference shielding films is a hot research topic. This work discusses the latest advances in flexible carbon‐based electromagnetic interference shielding films, such as constructing desirable structures, combining with magnetic constituents, and filling with polymer matrices. The new construction strategies, preparation methods, performances, and associated mechanisms are summarized. Moreover, the synergism, multifunctionality, and potential application of outstanding carbon‐based electromagnetic interference shielding films including graphene‐based, CNT‐based, and carbon fiber‐based films are analyzed in detail. Additionally, some significant issues and prospective views on carbon‐based composites as flexible electromagnetic interference shielding films are also presented.Highlights The latest progress of flexible carbon‐based EMI shielding films Constructing desirable structure, synergizing with others, designing CPCs The relationship between preparation, structure, property, and mechanisms The synergism, multifunctionality, application of EMI shielding films Key challenges and future perspectives of carbon‐based EMI shielding films

Superfast Phase Transformation Driven by Dual Chemical Equilibrium Enabling Enhanced Electrochemical Energy Storage

AbstractPhase transformation engineering provides new synthetic opportunities and pathways toward functional materials with desirable phases and structures. However, current phase transformation processes are generally time‐consuming or low‐yielding due to the lack of favorable driving forces. Herein, a superfast and scalable phase transformation technique driven by dual chemical equilibrium is developed. Taking manganese hexacyanoferrate (MnHCF) as an example, precipitation–dissolution and oxidation‐reduction dual chemical equilibrium co‐drive the superfast phase transformation from cubic KMnFe(CN)6 (C‐MnHCF) to monoclinic K2MnFe(CN)6 (M‐MnHCF) and simultaneously oxidative polymerization of polypyrrole (PPy), enabling the formation of homogeneous M‐MnHCF/PPy hybrid materials. For electrochemical energy storage, the uniform hybridization of PPy improves the electrical conductivity, restrains the dissolution of Mn, and more importantly, promotes K+‐intercalation kinetics of the K‐intercalated MnHCF‐based cathodes with a K+/Na+ competing insertion/extraction mechanism. As a result, the M‐MnHCF/PPy hybrid cathode manifests enhanced structural integrity and charge‐transport capability and thus long‐term cyclic life (114.8 mAh g−1 after 200 cycles at 0.1 A g−1) and high rate performance (113.3 and 92.7 mAh g−1 at 0.5 and 1 A g−1, respectively).

Large area nanoscale patterning of functional materials using organosilicate ink based nanotransfer printing

This paper presents a versatile nanotransfer printing method for achieving large-area sub-micron patterns of functional materials. Organosilicate ink formulations combined with effective release layers have been shown to facilitate patterning of materials through the commonly used patterning approaches—lift off, physical etching and chemical etching. In this paper, we demonstrate that organosilicate ink formulations function as an effective resist owing to its superior physico-chemical stability whereas the release layers ensure clean removal of the resist post patterning. We successfully demonstrate patterning of sub-micron structures (800 nm feature sizes) of chromium metal through the lift off approach, silicon through reactive ion etching technique and silicon dioxide through wet chemical etching technique illustrating the versatility of the reported method. This patterning methodology represents a significant advancement in enabling nanostructure fabrication within resource-constrained laboratories. The approach requires nothing more than a master mold containing the desired structures, a spin coater, a low-temperature hotplate, and a desktop reactive ion etch tool.

Two conjectures on 3D Voronoi structures: a toolkit with biomedical case studies.

3D Voronoi scaffolds are widely applied in the field of additive manufacturing as they are known for their light weight structural resilience and share many topological similarities to various natural (bone, tumours, lymph node) and synthetic environments (foam, functionally gradient porous materials). Unfortunately, the structural design features that promote these topological similarities (such as the number of vertices) are often unpredictable and require the trial and error of varying design features to achieve the desired 3D Voronoi structure. This article provides a toolkit, consisting of equations, based on over 12 000 3D Voronoi structures. These equations allow design features, such as the number of generating points (G), to be efficiently and accurately predicted based on the desired structural parameters (within ±3G). Based on these equations we are proposing, to the best of our knowledge, two new mathematical conjectures that relate the number of vertices or edges, and the average edge length to G in Voronoi structures. These equations have been validated for a wide range of parameter values and Voronoi network sizes. A design code is provided allowing any of over 12 000 structures to be selected, easily adjusted based on user requirements, and 3D printed. Biomedical case studies relevant to T-cell culturing, bone scaffolds and kidney tumours are presented to illustrate the design code.

Structural characterization of solvent-based food preparation of jellyfish.

Jellyfish as a potential sustainable food material has recently gained increasing interest. However, with their soft gel-like texture and easy spoilage, it remains challenging to achieve desirable edible structures from jellyfish. The culinary preparation of jellyfish is a complex process and extends beyond conventional cooking methods. In this study, we investigate the transformation of jellyfish into crispy-like structures by manipulating their microstructural and mechanical properties through a solvent-based preparation. The study focuses on the use of "poor solvents", namely ethanol and acetone, and employs rheology measurements and quantitative microscopy techniques to analyze the effects of these solvents on the mechanical properties and microstructure of jellyfish. Our findings reveal that both ethanol and acetone lead to a significant increase in jellyfish hardness and deswelling. Notably, a micro-scale network is formed within the jellyfish matrix, and this network is then mechanically reinforced before a crispy-like texture can be obtained. Our study points to solvent polarity as also being a crucial factor for creating these effects and determines an upper polarity limit in the range of 12.2-12.9 MPa1/2 for added solvents, corresponding to approximately 60% of added ethanol or 70% of added acetone. Our study highlights that solvent-based preparation serves as a "reverse cooking" technique, where mechanical modification rather than traditional softening mechanisms are employed to stabilize and strengthen the microstructures and fibers of jellyfish. By elucidating the underlying mechanisms of solvent-induced stabilization, our findings may facilitate the development of innovative and sustainable culinary practices, paving the way for broader applications of jellyfish and other soft edible materials in the gastronomic landscape.

Recent progress in 2D and 3D metal–organic framework-based membranes for water sustainability

Metal–organic frameworks (MOFs) have emerged as promising candidates for high-performance separation processes due to their desirable porous structure and highly tunable properties.

Functionalizable poly-terthiophene/Cu2O heterojunction constructed in situ for sensitive photoelectrochemical detection of long non-coding RNA markers.

A photoelectrochemical (PEC) sensor based on the poly-2,2,5,2-terthiophene (pTTh)/Cu2O heterojunction was constructed and applied for the detection of long non-coding RNA (lncRNA) TROJAN, a biomarker of triple-negative breast cancer. Cu2O and pTTh were electrodeposited in situ and sequentially onto an indium tin oxide substrate. The bandgap of the resultant type II heterojunction was measured spectroscopically and the morphology was found to effectively separate photogenerated holes from electrons. A photocurrent density as high as 250 μA cm-2 was attained, which is about three times higher than those of only pTTh or Cu2O. Owing to the close contact between pTTh and Cu2O, this PEC sensor is highly stable. Oligonucleotide probes for lncRNA can be cross-linked to carboxyl moieties of mercaptopropionic acid molecules adsorbed on pTTh/Cu2O. The desirable band structure and the high density of probe molecules collectively yielded a linear range of 0.1-10 000 pM. Our PEC sensor has been demonstrated to be amenable for detection of lncRNA markers with excellent analytical performance.

Pursuing theranostics: a multimodal architecture approach.

Theranostics is a field of nuclear medicine which uses the same targeting vector and chelating system for both a diagnostic and therapeutic radionuclide, allowing for uniformity in imaging and treatment. This growing field requires the development of more flexible chelate systems that permit novel targeting strategies. Toward this end, a multimodal architecture has been realized, making use of a phosphazene-based core and click chemistry to achieve a flexible and customizable scaffold. The six arm phosphazene-based core can scaffold six DTPA chelating motifs or a mixed set of 3 : 3 DTPA : DFO chelates resulting in two multimodal compounds, pDbDt and pDbDtDf, respectively. Terbium complexes displayed strong luminescence, supporting that the structures act as an organic antenna for luminescence. Metal displacement titration studies confirmed the desired structures as well as the capability for heterometallic labeling of the structures. These structures were found to have high thermal and biological stability in vitro. Radiolabeling of each compound resulted in high molar activity labeling of each compound: 169 MBq nmol-1: [161Tb]Tb-pDbDt, 170 MBq nmol-1: [89Zr]Zr-pDbDtDf, and the mixed radiolabeling illustrated chelation of both radionuclides in a 1 : 1 ratio. This multimodal architecture is promising as a heterometallic structure for coupling of both a diagnostic and a therapeutic radionuclide with a highly customizable core structure.

Sandwich-type channeled chemical hydrogels manufactured by 3D ink-jet printing under freezing conditions using a photochemical process for human cell cultures

This work aims to present the technology of preparing chemical hydrogels for cell culture by printing. It consists in drop-on-drop 3D ink-jet printing under freezing conditions of a solution containing a diacrylic compound (poly(ethylene glycol) diacrylate (PEGDA)) with an initiator (hydrogen peroxide) of photochemically induced polymerization and cross-linking. 3D printing takes place at a low temperature, thanks to which droplets of the solution immediately freeze, allowing the desired structures of the frozen solution to be built. UVC radiation of frozen structures at room temperature and in the presence of oxygen induces simultaneous melting and radical polymerization and cross-linking of PEGDA, resulting in the formation of a firm chemical hydrogel with the same shape as the shape of the printed frozen solution. Discussed are: (i) technological parameters, (ii) reaction mechanism, (iii) sol–gel analysis, (iv) morphology of printed hydrogels and (v) biocompatibility studies with the applied human fibroblasts, human umbilical vein endothelial cells and human neuroblastoma cells. A method for printing sandwich-type channeled structures was developed and shown in application for cell growth. This work demonstrates the feasibility of 3D printing biocompatible chemical hydrogels for cell culture and opens new possibilities for printing hybrid structures for biomedical applications.

Enhancing Carbon Fiber Properties through Lignin-Cellulose Composites: A Comparative Study of Hardwood Vs. Softwood Lignin Sources

Carbon fibers are integral to a wide range of applications, including automotive, construction, packaging, textiles, and emerging fields such as energy storage electrodes like flexible supercapacitors. However, concerns related to limited availability and environmental impact associated with fossil-based carbon fiber production have sparked growing interest in sustainable alternatives, particularly those derived from lignin and cellulose composites. This conference work presents a comparative analysis of the mechanical properties of lignin-cellulose composite carbon fibers derived from hardwood and softwood lignin sources, elucidating the significant influence of lignin origin on fiber performance.Our study focuses on the advantages and disadvantages of utilizing a composite of hardwood lignin vs. softwood lignin with cellulose in carbon fiber production, comparing these materials to commercially available carbon fibers. We emphasize the mechanical performance of these composite fibers, specifically highlighting the tensile strength and tensile modulus as a key metric. Notably, our results demonstrate that carbon fibers derived from hardwood lignin/cellulose composites exhibit superior mechanical strength compared to those from softwood lignin/cellulose composites. To gain fundamental insights into the reasons behind this mechanical disparity, we employed Raman spectroscopy to analyze the carbon structures within the fibers. Our findings revealed that carbon fibers produced from hardwood lignin exhibited a higher degree of graphitization, helping in achieving of typically desirable pre-graphite turbostractic carbon structures. These structural enhancements significantly contributed to the improved mechanical characteristics observed. In summary, our research underscores the critical importance of lignin source selection in the production of lignin-cellulose composite carbon fibers. The mechanical performance of these fibers is closely linked to the carbon morphology influenced by the lignin source. Therefore, understanding and controlling the lignin source from hardwood or softwood is pivotal for tailoring carbon fiber properties to meet specific application requirements. This study not only advances the knowledge in sustainable carbon fiber production but also offers valuable insights into achieving desirable properties for a wide range of applications, including advanced energy storage systems and structural materials.

(Invited) Design of Specific Polymer Binders for Stabilization of Si Based Anode in Lib

In recent years, intense efforts have been focused on stabilization of silicon-based anode in Li ion secondary batteries due to their remarkably high theoretical capacity. At the same time, strategy has not yet been established on how to stabilize the silicon based anode sufficiently during long cycles so that it will be feasible for practical use. In this talk, several different approaches on stabilization of silicon-based anode will be introduced both in terms of polymer binders design and active materials design. Our group synthesized several self-healing polymer binder and polymer coating material which are efficient for the use in silicon-based anode. Poly(borosiloxane) (PBS)1 was prepared by dehydrocoupling polymerization between mesitylborane and diphenylsilanediol in the presence of transition metal catalyst. PBS was found to show self-healing property at 45oC when coated onto Si electrode. When PBS coated Si electrode was employed for anodic half cell (Si/EC:DEC (1/1=v/v)/Li), it showed much improved durability when compared with PVDF coated Si based cell or bare Si based cell. We also reported a design of BIAN (bis-imino-acenaphthene) based conjugated polymer (P-BIAN) /Poly(acrylic acid) (PAA) composite binder for Si based anode2,3. Due to combination of n-type imine-based conjugated polymer (H-bonding acceptor) and PAA (H-bonding donor), synergistic effect in stabilization of Si/C composite anode was observed due to both of desirable electronic structure of P-BIAN and H-bonding based self-healing properties. In this system, anodic half cell delivered specific discharging capacity of above 2000 mAhg-1 for 600 cycles. As alternative approaches, we are also working on preparation of specific Si based anodic active materials which showed extremely high durability. b-SiC/N-doped carbon4 was found to show excellent durability even in the presence of conventional binder materials due to restricted volumetric changes of b-SiC during lithiation/delithiation. We also report coating of mechanically highly robust silicon oxycarbide on micro silicon5, which was also found to be quite effective.References1) Patnaik, S. G.; Jayakumar, T. P.; Sawamura, Y. Matsumi, N. ACS Appl. Ener. Mater. 2021, 4, 2241.2) Gupta, A.; Badam, R.; Matsumi, N. ACS Appl. Ener. Mater. 2022, 5, 7977.3) Gupta, A.; Badam, R.; Nag, A.; Kaneko, T.; Matsumi, N. ACS Appl. Ener. Mater. 2021, 4, 22314) Nandan, R.; Takamori, N.; Higashimine, K.; Badam, R.; Matsumi, N. J. Mater. Chem. A. 2022, 10, 5230.5) Nandan, R.; Takamori, N.; Higashimine, K.; Badam, R.; Matsumi, N. J. Mater. Chem. A. 2022, 10, 15960.

(Invited) Direct Laser Induced Gold Wiring of 2D Materials with Sub-Μm Resolution

One of the most influential technologies of our modern world are integrated electronics. Almost all parts of our daily life include some bearing with any kind of electrical technologies. The fabrication methods itself, for integrated miniatured electrical devices have had not much innovation in terms of production. Several processing steps still mainly consist of different kinds of lithography. This situation may change with new challenges on the production of smaller quantities with specialized functions, or the use of temperature critical or atomically thin surfaces, where the thermal evaporation of metals damages the sample.For some decades now, printing of all types of electronics have gained great attraction. While lithography is a time-consuming multi-step process (including resist preparation, illuminating, developing, evaporation and lift-off) with expensive and harmful photoresists and harsh environmental conditions (high-vacuum and thermal treatments), ink printing allows for direct and simple application of the desired structures [1]. Two main types of inks are typically applied: colloidal solutions of metal nanoparticles [2, 3] or metal-organic precursor solutions [4]. In both cases, thermal curing after deposition is required to achieve metallic conduction. To this end, laser writing is often advantageous over thermal sintering due to the overall lower thermal stress applied to the material, particularly on flexible, thermally sensitive substrates [5] whereas metal nanoparticles suffer from a relatively high photothermal stability and the need for a large laser power to achieve sufficient sintering [3]. In contrast, metal-organic precursor solutions feature a relatively low metal content (≤34 wt-%)10, and undergo large volume contractions during laser writing. These challenges have so far prevented the definition of metallic gold contacts with diffraction-limited feature sizes by ink printing and laser writing.Here, we introduce atomically-precise, metalloid Au32(nBuP12Cl8) nanoclusters (Au32NCs) [6] as an ink for resistless, direct laser writing of metallic gold micro- and nanostructures. The unique advantages of this ink over Au nanoparticles or typical metal-organic Au precursors are their high photosensitivity in combination with a large gold content of 70 wt-%. This allows for writing gold structures with feature sizes of 250 nm and line spacings < 200 nm using 1.86 mW laser power at 488 nm with a scan speed of 0.1 mm/s. We apply this method on a wide range of substrates, including flexible polymer membranes, find metallic conductance with conductivities ~ 1 × 106 S/m and demonstrate that defining such Au contacts on two-dimensional semiconductors results in fully functional optical switches and field effect transistors made out from 2D materials.[1] Raut NC. et al., Jour. Mat. Chem. C 2018, 6(7): 1618-1641.[2] Ko E. et al., Nanotechnology 2007, 18(34): 345202.[3] Hong S. et al., ACS Nano 2013, 7(6): 5024-5031.[4] Schoner C et al., Thin Solid Films 2013, 531: 147-151.[5] Skylar-Scott MA et al., PNAS 2016, 113(22): 6137-6142.[6] Kenzler S et al., Angew. Chem. Int. Ed. 2019, 58(18): 5902-5905. Figure 1