arXiv subjects

Borja Rodriguez-Barea

Publications and source records attributed to Borja Rodriguez-Barea.

4 recordsLinked to original sources

arXiv2025

DNA mold-based fabrication of continuous silver nanostructures

Bottom-up fabrication of inorganic nanostructures is emerging as an alternative to classical top-down approaches, offering precise nanometer-scale control at relatively low cost and effort. In particular, DNA nanostructures provide versatile scaffolds for directly templating the growth of metal structures. Previously, a DNA mold-based method for metal nanostructure synthesis has been established that supports a modular structure design and a high control over the structure formation. So far, this method was limited to the growth of gold and palladium nanostructures. Here, we report the successful adaptation of the DNA mold-based fabrication method to produce continuous silver nanowires. By optimizing reagent concentrations and applying gentle thermal annealing, we obtain continuous wire structures of several hundred nanometer length, overcoming limitations in anisotropic growth. Despite the strong interaction of silver ions with DNA, we can control the growth without increasing the complexity of our approach. Our structures are not oxidized yet they did not exhibit conductivity. This work demonstrates the versatility of DNA-templated metallization and opens new opportunities for constructing self-assembled hybrid nanostructures with controlled shape and composition.

cond-mat.mtrl-sci↗

arXiv2025

Nanoscale Charge Transport in Au@PANI Assemblies: Bulk-like Films and Linear Assemblies

Hybrid nanostructures from metal nanoparticles equipped with conducting polymer shells are of great interest for use as functional materials in sensing and optoelectronics, as well as for ink-deposited conductors. Here, we investigate the charge transport mechanism of nanostructures composed of gold nanoparticles coated with a polyaniline shell (Au@PANI). In particular, we focus on how geometry influences the charge transport behavior. Highly ordered linear assemblies of Au@PANI nanoparticles were fabricated using template-assisted assembly, while bulk-like films were obtained via drop-casting. Temperature-dependent transport measurements were analyzed using established conductance models. Linear assemblies exhibit more localized transport, characterized by variable-range hopping (VRH) and thermally assisted tunneling (TAT), whereas bulk-like films show more delocalized transport, dominated by Arrhenius-type and thermionic conduction. These findings highlight the critical role of geometry, also due to its effect on electrical field strength in determining charge transport mechanisms in nanoparticle-based hybrid systems.

physics.app-ph↗

arXiv2025

Intrinsic Resistive Switching in Microtubule-Templated Gold Nanowires for Reconfigurable Nanoelectronics

The scaling limitations of conventional transistors demand alternative device concepts capable of dynamic reconfigurability at the atomic scale. Resistive switching (RS), a key mechanism for neuromorphic computing and non-volatile memory, has been widely demonstrated in oxides, semiconductors, and nanocomposites, but not in pure one-dimensional metallic systems. Here, we report the first electrical characterization of gold nanowires (AuNWs) synthesized within the lumen of functionalized microtubules. Structural analyses confirm continuous metallic wires with local compositional inhomogeneities. Electrical measurements reveal three distinct conduction behaviours and abrupt, reversible resistance transitions under applied bias, consistent with defect-driven electromigration. Voltage pulsing enables active and reproducible modulation of resistance states without loss of metallic conduction, establishing a new RS mechanism intrinsic to pure metallic nanowires. Owing to their high aspect ratio, lateral geometry, and CMOS-compatible processing, microtubule-templated AuNWs provide a versatile platform for reconfigurable interconnects and neuromorphic device architectures.

cond-mat.soft↗

arXiv2025

Molecular Cross-linking of MXenes: Tunable Interfaces and Chemiresistive Sensing

MXenes, a family of 2D transition metal compounds, have emerged as promising materials due to their unique electronic properties and tunable surface chemistry. However, the translation of these nanoscale properties into macroscopic devices is constrained by suitable cross-linking strategies that enable both processability and controlled inter-flake charge transport. Herein, we demonstrate the tunability of interfaces and the inter-layer spacing between Ti$_3$C$_2$T$_x$ MXene flakes through molecular cross-linking with homologous diamines. Oleylamine was first used to stabilize MXenes in chloroform, followed by diamine-mediated cross-linking to tune precisely the interlayer spacing. Grazing incidence X-ray scattering (GIXRD/GIWAXS) confirmed the correlation between ligand chain length and inter-layer spacing, which was further supported by Density Functional Theory (DFT) calculations. Furthermore, we investigated the charge transport properties of thin films consisting of these diamine-crosslinked Ti$_3$C$_2$T$_x$ MXenes and observed a strong dependence of the conductivity on the interlayer spacing. The dominating charge transport mechanism is variable range hopping (VRH) in accordance with the structure analysis of the films. Finally, we probed chemiresistive vapor sensing in MXene composites, observing pronounced water sensitivity and selectivity, highlighting their potential for use in humidity sensors. Insights into molecular cross-linking and its impact on charge transport open avenues for next-generation MXene-based electronic devices.

cond-mat.mtrl-sci↗