Nanomaterials

15 pages, 1551 KB

Open AccessArticle

Photogating Regimes in Graphene: Memory-Bearing and Reset-Free Operation

by Afshan Khaliq, Hongsheng Xu, Akeel Qadir, Ayesha Salman, Sichao Du, Munir Ali and Shihua Huang

Nanomaterials 2025, 15(21), 1667; https://doi.org/10.3390/nano15211667 (registering DOI) - 2 Nov 2025

Abstract

We demonstrate photogating in a graphene/Si–SiO₂ stack, where vertical motion of photogenerated charge is converted into a corresponding change in graphene channel conductance in real time. Under pulsed illumination, holes accumulate at the Si/SiO₂ interface, creating a surface photovoltage that shifts [...] Read more.

We demonstrate photogating in a graphene/Si–SiO₂ stack, where vertical motion of photogenerated charge is converted into a corresponding change in graphene channel conductance in real time. Under pulsed illumination, holes accumulate at the Si/SiO₂ interface, creating a surface photovoltage that shifts the flat-band condition and electrostatically suppresses graphene conductance. A dual-readout scheme—simultaneously tracking interfacial charging dynamics and the graphene channel—cleanly separates optical charge injection (cause) from electronic transduction (effect). This separation allows for the direct extraction of practical figures of merit without conventional transfer sweeps, including flat-band shift per pulse, retention time constants, and trap occupancy. Interface kinetics then define two operating regimes: a fast, resettable detector when traps are sparse or rapid, and a trap-assisted analog-memory state when slow traps retain charge between pulses. The mechanism is CMOS-compatible and needs no cryogenics or exotic materials. Together, these results outline a compact route to engineer integrating photodetectors, pixel-level memory for adaptive imaging, and neuromorphic optoelectronic elements that couple sensing with in situ computation. Full article

(This article belongs to the Special Issue 2D Materials for High-Performance Optoelectronics)

15 pages, 2467 KB

Open AccessArticle

Waste Oyster Shell/Graphene Oxide Composite as a Dual-Functional Soil Conditioner and SRF: Impacts on Soil pH and Nutrient Availability

by Hsuhui Cheng, Yuxing Xian, Yetong Lu, Ziying Zhang, Yishi He and Xiangying Hao

Nanomaterials 2025, 15(21), 1666; https://doi.org/10.3390/nano15211666 (registering DOI) - 1 Nov 2025

Abstract

Graphene oxide (GO) was prepared by a waterless synthesis route to generate GO sheets, which were then applied to coat calcined oyster shell with fertilizer (OSF) pellets, resulting in the creation of an OSF-GO particle. The GO sheets (ID/IG = 0.86) were characterized [...] Read more.

Graphene oxide (GO) was prepared by a waterless synthesis route to generate GO sheets, which were then applied to coat calcined oyster shell with fertilizer (OSF) pellets, resulting in the creation of an OSF-GO particle. The GO sheets (ID/IG = 0.86) were characterized by Raman spectroscopy, which showed that the GO-coated OSF pellet features a compact coating approximately 13.68 μm thick. SEM and AFM analyses revealed that the GO sheets displayed a monolayer configuration with a crinkled topography (about 0.91 nm). The EDS analysis confirmed that the core was primarily composed of Ca, K, P, O, N, and C elements. The hydroponic experiment results showed that a GO concentration of 80 mg/L significantly enhanced plant height, stem thickness, and root length in loose-leaf lettuce, while higher concentrations induced oxidative stress. In pot experiments, the OSF-GO composite effectively raised the soil pH from 5.38 to 6.41 and improved nutrient availability. OSF-GO composite functions effectively as both a soil conditioner and slow-release fertilizer (SRF), simultaneously remediating degraded soils and optimizing nutrient delivery. Full article

(This article belongs to the Special Issue Interplay between Nanomaterials and Plants)

33 pages, 4280 KB

Open AccessReview

Advances in Through-Hole Anodic Aluminum Oxide (AAO) Membrane and Its Applications: A Review

by Chin-An Ku and Chen-Kuei Chung

Nanomaterials 2025, 15(21), 1665; https://doi.org/10.3390/nano15211665 (registering DOI) - 1 Nov 2025

Abstract

Anodic aluminum oxide (AAO) is a well-known nanomaterial template formed under specific electrochemical conditions. By adjusting voltage, temperature, electrolyte type, and concentration, various microstructural modifications of AAO can be achieved within its hexagonally arranged pore array. To enable broader applications or enhance performance, [...] Read more.

Anodic aluminum oxide (AAO) is a well-known nanomaterial template formed under specific electrochemical conditions. By adjusting voltage, temperature, electrolyte type, and concentration, various microstructural modifications of AAO can be achieved within its hexagonally arranged pore array. To enable broader applications or enhance performance, post-treatment is often employed to further modify its nanostructure after anodization. Among these post-treatment techniques, AAO membrane detachment methods have been widely studied and can be categorized into traditional etching methods, voltage reduction methods, reverse bias voltage detachment methods, pulse voltage detachment methods, and further anodization techniques. Among various delamination processes, the mechanism is highly related to the selectivity of wet etching, as well as the Joule heating and stress generated during the process. Each of these detachment methods has its own advantages and drawbacks, including processing time, complexity, film integrity, and the toxicity of the solutions used. Consequently, researchers have devoted significant effort to optimizing and improving these techniques. Furthermore, through-hole AAO membranes have been applied in various fields, such as humidity sensors, nanomaterial synthesis, filtration, surface-enhanced Raman scattering (SERS), and tribo-electrical nano-generators (TENG). In particular, the rough and porous structures formed at the bottom of AAO films significantly enhance sensor performance. Depending on specific application requirements, selecting or refining the appropriate processing method is crucial to achieving optimal results. As a versatile nanomaterial template, AAO itself is expected to play a key role in future advancements in environmental safety, bio-applications, energy technologies, and food safety. Full article

(This article belongs to the Special Issue Research for Food Contact Materials and Sensors Based on Nanomaterials)

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13 pages, 6341 KB

Open AccessArticle

GaAs Nanowire Growth by MBE with Catalyst Forming Eutectic Points with Both Elements

by Nickolay V. Sibirev, Ilya P. Soshnikov, Igor V. Ilkiv, Evgenii V. Ubyivovk, George E. Cirlin and Igor V. Shtrom

Nanomaterials 2025, 15(21), 1664; https://doi.org/10.3390/nano15211664 (registering DOI) - 1 Nov 2025

Abstract

A3B5 nanowires are usually grown via the vapor-liquid-solid mechanism. Species from the vapor are incorporated into the nanowires using a catalyst droplet. Typically, the droplet is a low-melting-point eutectic alloy of catalyst and group III metal. This growth imposes a set of limitations [...] Read more.

A3B5 nanowires are usually grown via the vapor-liquid-solid mechanism. Species from the vapor are incorporated into the nanowires using a catalyst droplet. Typically, the droplet is a low-melting-point eutectic alloy of catalyst and group III metal. This growth imposes a set of limitations on the heterostructure formation and doping. Axial A3B5 heterostructure nanowires obtained via an interchange of group III metals suffer from blurring and kinking. Amphoteric dopants such as Si could act as donors and acceptors, leading to electron-to-hole ratio oscillations along the nanowire. To overcome these limits, the growth with a catalyst, which could dissolve both components of the nanowire, is studied. Tin has a eutectic with both components, As and Ga. This makes the growth of GaAs nanowires with a tin catalyst different from that with standard catalysts. Nanowire growth occurs with at least two types of catalysts, Ga-rich and Ga-poor (As-rich). This article aims to study the nanowire growth with an Sn catalyst. For the first time, the growth of GaAs nanowires using a tin catalyst by molecular beam epitaxy is shown. Tin can serve as a catalyst not only for the chemical growth of GaAs nanowires but also as a nucleation site for their growth. Both compositions of the catalyst are observed. The annealing of a thin film of tin on a Si and GaAs substrate has also been studied. At temperatures below 450 °C, small metal droplets form, while tin dissolves into the substrate at higher temperatures. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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19 pages, 3110 KB

Open AccessArticle

Low-Cost Versatile Microfluidic Platform for Bioorthogonal Click-Mediated Nanoassembly of Hybrid Nanosystems

by Javier González-Larre, María Amor García del Cid, Diana Benita-Donadios, Ángel Vela-Cruz, Sandra Jiménez-Falcao and Alejandro Baeza

Nanomaterials 2025, 15(21), 1663; https://doi.org/10.3390/nano15211663 (registering DOI) - 1 Nov 2025

Abstract

In recent years the global market of nanomedicine has experienced incredible growth owing to the advances in the field. This translation of the technique to the biomedical industry requires the development of production methods that deliver nanomedicines with a high degree of reproducibility [...] Read more.

In recent years the global market of nanomedicine has experienced incredible growth owing to the advances in the field. This translation of the technique to the biomedical industry requires the development of production methods that deliver nanomedicines with a high degree of reproducibility between batches, combined with cost and time efficiency. The use of nanoparticles in medicine usually requires their surface functionalization to improve biocompatibility in addition to providing targeting capacities and/or stimuli-responsive behavior, among other interesting skills. Microfluidic technology has revolutionized the field both in nanomedicine synthesis and in preclinical evaluation. However, microfluidic-assisted synthetic procedures commonly require high-cost methods and equipment to fabricate the microreactors. The aim of this work is to present an ultra-low-cost microfluidic platform that permits the versatile modification of nanomaterials. To prove this approach, two different model nanoparticles with different natures: soft nanoparticles (liposomes) and rigid nanoparticles (mesoporous silica) have been decorated both with small molecules and with other nanoparticles, respectively, in order to evaluate the scope of this approach. The anchoring of the covalently attached elements has been performed using click chemistry, in compliance with the principles for further transfer to the drug industry. Full article

(This article belongs to the Special Issue Latest Research on Nanomedicine and Drug Delivery Using Inorganic Nanoparticles)

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4 pages, 160 KB

Open AccessEditorial

Advanced Nanoscale Materials and (Flexible) Devices

by Kaiwen Lin, Chunhui Duan and Baoyang Lu

Nanomaterials 2025, 15(21), 1662; https://doi.org/10.3390/nano15211662 (registering DOI) - 1 Nov 2025

Abstract

The fusion of nanoscience and mechanically compliant systems is redefining the performance boundaries of electronics, photonics, energy, and sensing technologies [...] Full article

(This article belongs to the Special Issue Advanced Nanoscale Materials and (Flexible) Devices)

12 pages, 3149 KB

Open AccessArticle

Phase-Controlled Synthesis of Alloyed (CdS)_x(CuInS₂)_1−x Nanocrystals with Tunable Band Gap

by Bingqian Zu, Song Chen, Liping Bao, Yingjie Liu and Liang Wu

Nanomaterials 2025, 15(21), 1661; https://doi.org/10.3390/nano15211661 (registering DOI) - 1 Nov 2025

Abstract

Phase and band gap engineering of (CdS)_x(CuInS₂)_1−x nanomaterials is critical for their potential applications in photovoltaics and photocatalysis, yet it remains a challenge. Here, we report a precursor-mediated colloidal method for phase-control synthesis of alloyed (CdS)_x(CuInS [...] Read more.

Phase and band gap engineering of (CdS)_x(CuInS₂)_1−x nanomaterials is critical for their potential applications in photovoltaics and photocatalysis, yet it remains a challenge. Here, we report a precursor-mediated colloidal method for phase-control synthesis of alloyed (CdS)_x(CuInS₂)_1−x nanocrystals with tunable band gap. When CuCl, InCl₃, and Cd(AC)₂·2H₂O are used as the respective cation sources, wurtzite-structured alloyed (CdS)_x(CuInS₂)_1−x nanocrystals can be synthesized with a tunable optical band gap ranging from 1.56 to 2.45 eV by directly controlling the molar ratio of the Cd precursor. Moreover, using Cu(S₂CNEt₂)₂, In(S₂CNEt₂)₃, and Cd(S₂CNEt₂)₂ as cation sources results in alloyed (CdS)_x(CuInS₂)_1−x nanocrystals with a zinc-blende structure, demonstrating that the optical band gap of these nanocrystals can be compositionally tuned from 1.50 to 1.84 eV through precisely adjusting the molar ratio of Cd precursor. The results were validated through a comprehensive characterization approach employing XRD, TEM, HRTEM, STEM-EDS, XPS, UV-vis-NIR absorption spectroscopy, and Mott–Schottky analysis. Full article

(This article belongs to the Special Issue Preparation and Characterization of Nanomaterials)

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26 pages, 1953 KB

Open AccessReview

Machine Learning for Thermal Transport Prediction in Nanoporous Materials: Progress, Challenges, and Opportunities

by Amirehsan Ghasemi and Murat Barisik

Nanomaterials 2025, 15(21), 1660; https://doi.org/10.3390/nano15211660 (registering DOI) - 31 Oct 2025

Abstract

Predicting the thermal properties of nanoporous materials is a major challenge that affects their applications in efficient thermal insulation and energy storage. This narrative review discusses the application of machine learning models in nanoporous materials, including covalent organic frameworks, metal–organic frameworks, aerogels, and [...] Read more.

Predicting the thermal properties of nanoporous materials is a major challenge that affects their applications in efficient thermal insulation and energy storage. This narrative review discusses the application of machine learning models in nanoporous materials, including covalent organic frameworks, metal–organic frameworks, aerogels, and zeolites. It discusses model advancements, with a focus on predictive accuracy and computational efficiency. This includes models such as convolutional neural networks, graph neural networks, and physics-informed neural networks. This study also addresses the limitations of these data-driven models, including data availability, challenges in maintaining physical consistency, and difficulties in generalizing across various material families. Additionally, it covers emerging approaches such as multimodal and transfer learning, which are explored for their potential to reduce computational costs. Moreover, the benefits of interpretable machine learning methods for understanding underlying physical mechanisms are introduced and highlighted. This review provides comprehensive and practical guidelines for researchers using machine learning approaches in the study and design of nanoporous materials. Full article

(This article belongs to the Special Issue Advances of Machine Learning in Nanoscale Materials Science)

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21 pages, 1293 KB

Open AccessReview

Innovative Application of Nanomaterials in Vegetable Cultivation: Recent Advances in Growth Promotion and Stress Tolerance

by Wenxuan Lv, Yixue Bai, Dongyang Zhu, Changzheng He, Fengjiao Bu, Yusong Luo, Ping Zhao, Yanhong Qiu, Zunzheng Wei, Jie Zhang, Shaogui Guo, Yongtao Yu, Jingfang Wang, Yi Ren, Guoyi Gong, Haiying Zhang, Yong Xu, Guang Liu, Sihui Dai and Maoying Li

Nanomaterials 2025, 15(21), 1659; https://doi.org/10.3390/nano15211659 (registering DOI) - 31 Oct 2025

Abstract

Vegetables are crucial to human diet and health. To ensure sustainable vegetable production, regulatory measures are needed to enhance seed germination, plant growth, and resilience to extreme environmental conditions. Nanomaterials (NMs), owing to their high surface area, nanoscale dimensions, and unique photocatalytic properties, [...] Read more.

Vegetables are crucial to human diet and health. To ensure sustainable vegetable production, regulatory measures are needed to enhance seed germination, plant growth, and resilience to extreme environmental conditions. Nanomaterials (NMs), owing to their high surface area, nanoscale dimensions, and unique photocatalytic properties, exhibit remarkable biological effects, such as promoting germination and growth, as well as improving stress resistance in crops, offering novel solutions to key challenges in vegetable cultivation. This review summarizes the absorption pathways of NMs in plants, specifically through the leaves and roots of vegetables. Their uptake and translocation occur via passive diffusion, active transport, and endocytosis, with key influencing factors including particle size, chemical composition, surface charge, and surface modifications. We further evaluate the advantages of nanofertilizers and nanopesticides, in vegetable production over their traditional counterparts, focusing on improvements in seed germination rates, seedling vigor, biotic and abiotic stress tolerance, and overall yield and quality. Through this review, we aim to offer comprehensive insights into the application of NMs in vegetable crop production. Full article

(This article belongs to the Special Issue Applications and Research of Nanocarriers and Nanopesticides in Agriculture)

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19 pages, 4132 KB

Open AccessArticle

Robust and Multi-Functional Electrically Responsive Gold/Polydopamine-Coated Liquid Crystalline Elastomer Artificial Muscles

by Joshua C. Ince, Setareh Elyasi, Alan R. Duffy and Nisa V. Salim

Nanomaterials 2025, 15(21), 1658; https://doi.org/10.3390/nano15211658 (registering DOI) - 31 Oct 2025

Abstract

Applying thin electrically conductive coatings to Liquid Crystalline Elastomers (LCEs) is an effective way of functionalizing two-way shape memory polymers with the ability to respond to electrical currents. However, achieving robust adhesion between a given electrically conductive coating and the surface of LCEs [...] Read more.

Applying thin electrically conductive coatings to Liquid Crystalline Elastomers (LCEs) is an effective way of functionalizing two-way shape memory polymers with the ability to respond to electrical currents. However, achieving robust adhesion between a given electrically conductive coating and the surface of LCEs can be challenging. This can limit the functionality, performance, and potential applications of these materials. This work describes a facile method to develop electrically responsive Liquid Crystalline Elastomer polymeric artificial muscles with strain-sensing, self-actuation-sensing, and joule-heating features. In this work, the effect of treating LCEs with polydopamine (PDA) prior to functionalizing the LCE with an electrically conductive gold-sputtered coating was explored. The findings confirmed that the PDA treatment considerably improved the adhesion of the gold sputter coating to the LCEs, thereby leading to the fabrication of multi-functional strain-sensing, electrically conductive, and electro-responsive LCEs. Full article

(This article belongs to the Special Issue Functional Nanomaterials for Sensing Devices: Synthesis, Characterization and Applications (2nd Edition))

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26 pages, 5510 KB

Open AccessArticle

One-Step Synthesized Folic Acid-Based Carbon Dots: A Biocompatible Nanomaterial for the Treatment of Bacterial Infections in Lung Pathologies

by Gennaro Longobardo, Francesca Della Sala, Giuseppe Marino, Marco Barretta, Mario Forte, Rubina Paradiso, Giorgia Borriello and Assunta Borzacchiello

Nanomaterials 2025, 15(21), 1657; https://doi.org/10.3390/nano15211657 - 30 Oct 2025

Abstract

Bacterial infections are a major complication in chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS), where mucus accumulation and pH fluctuations further hinder treatment. Nanostructured systems such as carbon dots (CDs) are increasingly investigated as antimicrobial agents due to their [...] Read more.

Bacterial infections are a major complication in chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS), where mucus accumulation and pH fluctuations further hinder treatment. Nanostructured systems such as carbon dots (CDs) are increasingly investigated as antimicrobial agents due to their scalability, low cost, and biocompatibility, compared to conventional antibiotics. Here, CDs were synthesized by a one-step microwave-assisted method at three reaction temperatures (130 °C, 170 °C, and 185 °C, named LT-CDs, MT-CDs, HT-CDs, respectively) to explore the effect of carbonization on their structure and function. TEM, Raman, and FTIR analyses were employed to investigate the size and distribution of carbon groups. UV–vis confirmed distinct pH-dependent spectral responses, and mucoadhesion studies revealed stronger and more stable interactions for MT-CDs. Biological assays demonstrated high biocompatibility across all samples on lung fibroblasts, while antimicrobial tests highlighted a selective effect against Staphylococcus aureus, due to ROS generation. Overall, MT-CDs represented the best compromise in terms of size, functionalization, biocompatibility, mucoadhesion, and antimicrobial activity, emerging as promising nanoplatforms for respiratory infection management in COPD and ARDS. Full article

(This article belongs to the Section Biology and Medicines)

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37 pages, 5698 KB

Open AccessArticle

Design and Optimization of Self-Powered Photodetector Using Lead-Free Halide Perovskite Ba₃SbI₃: Insights from DFT and SCAPS-1D

by Salah Abdo, Ambali Alade Odebowale, Amer Abdulghani, Khalil As’ham, Yacine Djalab, Nicholas Kanizaj and Andrey E. Miroshnichenko

Nanomaterials 2025, 15(21), 1656; https://doi.org/10.3390/nano15211656 - 30 Oct 2025

Abstract

All-inorganic halide perovskites have attracted significant interest in photodetector applications due to their remarkable photoresponse properties. However, the toxicity and instability of lead-based perovskites hinder their commercialization. In this work, we propose cubic Ba₃SbI₃ as a promising, environmentally friendly, lead-free [...] Read more.

All-inorganic halide perovskites have attracted significant interest in photodetector applications due to their remarkable photoresponse properties. However, the toxicity and instability of lead-based perovskites hinder their commercialization. In this work, we propose cubic Ba₃SbI₃ as a promising, environmentally friendly, lead-free material for next-generation photodetector applications. Ba₃SbI₃ shows good light absorption, low effective masses, and favorable elemental abundance and cost, making it a promising candidate compound for device applications. Its structural, mechanical, electronic, and optical properties were systematically investigated using density functional theory (DFT) with the Perdew–Burke–Ernzerhof (PBE) and hybrid HSE06 functionals. The material was found to be dynamically and mechanically stable, with a direct bandgap of 0.78 eV (PBE) and 1.602 eV (HSE06). Photodetector performance was then simulated in an Al/FTO/In₂S₃/Ba₃SbI₃/Sb₂S₃/Ni configuration using SCAPS-1D. To optimize device efficiency, the width, dopant level, and bulk concentration for each layer of the gadgets were systematically modified, while the effects of interface defects, operating temperature, and series and shunt resistances were also evaluated. The optimized device achieved an open-circuit voltage (Voc) of 1.047 V, short-circuit current density (Jsc) of 31.65 mA/cm², responsivity of 0.605 A W⁻¹, and detectivity of 1.05 × 10¹⁷ Jones. In contrast, in the absence of the Sb₂S₃ layer, the performance was reduced to a Voc of 0.83 V, Jsc of 26.8 mA/cm², responsivity of 0.51 A W⁻¹, and detectivity of 1.5 × 10¹⁵ Jones. These results highlight Ba₃SbI₃ as a promising platform for high-performance, cost-effective, and environmentally benign photodetectors. Full article

(This article belongs to the Special Issue Advances in Nanostructured Metal Halide Perovskites for Optoelectronics: Materials, Devices and Commercialization)

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19 pages, 6189 KB

Open AccessArticle

Optimizing the Tribological Performance of Graphite–Resin Composites: The Role of High Crystallinity, Nano Morphology, and Hydrophobic Surface Modification

by So-jung Baek, Yeo-jin Tak, Da-hyun Yu, Seong-yeon Park, Do-hyun Um and Kwang-youn Cho

Nanomaterials 2025, 15(21), 1655; https://doi.org/10.3390/nano15211655 - 30 Oct 2025

Abstract

Graphite, with its layered structure and weak van der Waals bonding between graphene nano layers, exhibits excellent self-lubricating properties. Natural graphite, characterized by high crystallinity, and artificial graphite, with relatively low crystallinity, exhibit distinct friction behaviors and structural differences, which significantly influence the [...] Read more.

Graphite, with its layered structure and weak van der Waals bonding between graphene nano layers, exhibits excellent self-lubricating properties. Natural graphite, characterized by high crystallinity, and artificial graphite, with relatively low crystallinity, exhibit distinct friction behaviors and structural differences, which significantly influence the performance of graphite–resin composites as solid lubricants. This study investigates the effects of natural/artificial graphite ratios and hydrophobic silane coupling treatment on the oil impregnation behavior, friction coefficient, wear stability, and microstructural changes in graphite–resin composites. Under a vertical load of 88,260 N and surface pressure of 50 MPa, the impregnated graphite–resin composites demonstrated low friction coefficients and stable wear behavior. SEM analysis revealed well-preserved microstructures, and Raman spectroscopy confirmed the formation of stable lubrication films through the I_D/I_G ratio, indicating graphene exfoliation. The results indicate that natural graphite provides dense structures and stable friction, while artificial graphite enhances oil impregnation but leads to unstable friction behavior. Full article

(This article belongs to the Section 2D and Carbon Nanomaterials)

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12 pages, 2177 KB

Open AccessArticle

A Sweat Cortisol Sensor Based on Gold-Modified Molecularly Imprinted Polymer

by Ziyu Liu, Guangzhong Xie, Jing Li, Hong Yuan and Yuanjie Su

Nanomaterials 2025, 15(21), 1654; https://doi.org/10.3390/nano15211654 - 30 Oct 2025

Abstract

Approximately 3.8% of the global population suffers from depressive disorders, posing a substantial public health challenge exacerbated by the COVID-19 pandemic due to widespread unemployment and prolonged social isolation. The difficulty in objectively quantifying psychological states underscores the need for effective stress assessment [...] Read more.

Approximately 3.8% of the global population suffers from depressive disorders, posing a substantial public health challenge exacerbated by the COVID-19 pandemic due to widespread unemployment and prolonged social isolation. The difficulty in objectively quantifying psychological states underscores the need for effective stress assessment methods. Herein, we developed a portable electrochemical cortisol sensor (PECS) for accurate mental stress assessment. The PECS consists of a screen-printed carbon electrode decorated with gold nanoparticles and a molecularly imprinted polymer (MIP) synthesized via electropolymerization. The as-prepared PECS demonstrates a wide and linear detection range from 1 fM to 1 μM, an ultra-low detection limit of 0.4112 fM and a high sensitivity of 15.518 nA∙lg(nM⁻¹)∙cm⁻². This work provides new possibility of developing soft bioelectronics for non-invasive and real-time mental health monitoring. Full article

(This article belongs to the Special Issue Application of Nanoscale Smart Textiles in Wearable Sensors)

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19 pages, 10608 KB

Open AccessArticle

1T-ZrS₂ Monolayer Decorated with Sc, Ti, and V Single Atoms: A Potential Gas Scavenger for NO_x and SO₂

by Xiaoxuan Wang, Jiaqi Zhang, Jinjuan Zhang, Xiaoqing Liu, Yuanqi Lin, Fangfang Li, Guangwei Wang, Yan Xu and Peng Wang

Nanomaterials 2025, 15(21), 1653; https://doi.org/10.3390/nano15211653 - 29 Oct 2025

Abstract

The intensification of industrialization and increasing energy consumption have led to elevated emissions of hazardous gases such as NO, NO₂, and SO₂, making their efficient capture and removal crucial for environmental remediation. In this work, first-principles calculations were employed [...] Read more.

The intensification of industrialization and increasing energy consumption have led to elevated emissions of hazardous gases such as NO, NO₂, and SO₂, making their efficient capture and removal crucial for environmental remediation. In this work, first-principles calculations were employed to systematically investigate the adsorption behavior of these gases on single-atom-decorated (Sc, Ti, and V) 1T-ZrS₂ monolayers. The results indicate that the transition metal atoms preferentially occupy the hexagonal hollow sites of ZrS₂, forming an approximately octahedral coordination field and exhibiting characteristic d-orbital splitting. During gas adsorption, the decorated systems exhibit pronounced metal-to-adsorbate charge donation and strong d-p hybridization, indicative of strong chemisorption. Notably, Ti-ZrS₂ exhibits the strongest adsorption toward NO₂, inducing partial molecular dissociation and suggesting catalytic activity, whereas Sc- and V-decorated systems predominantly maintain molecular adsorption. Recovery time calculations indicate that the adsorption processes are comparatively stable, making these systems suitable for gas capture and pollution abatement. Overall, single-atom decoration provides an effective strategy to modulate the electronic structure and gas interactions of ZrS₂, highlighting its potential as an efficient gas scavenger for NO, NO₂, and SO₂. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

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12 pages, 1363 KB

Open AccessArticle

Physical Properties of New Silica-Based Denture Surface Coating

by Kazuhiro Akutsu-Suyama, Reiko Tokuyama-Toda, Chiaki Tsutsumi-Arai, Chika Terada-Ito, Yoko Iwamiya, Zenji Hiroi, Mitsuhiro Shibayama and Kazuhito Satomura

Nanomaterials 2025, 15(21), 1652; https://doi.org/10.3390/nano15211652 - 29 Oct 2025

Abstract

Denture stomatitis is a common issue among denture users, primarily caused by pathogenic microorganisms such as Candida albicans that adhere to and multiply on the denture surface. While previous approaches have focused on incorporating antimicrobial agents into denture base resins, this study introduces [...] Read more.

Denture stomatitis is a common issue among denture users, primarily caused by pathogenic microorganisms such as Candida albicans that adhere to and multiply on the denture surface. While previous approaches have focused on incorporating antimicrobial agents into denture base resins, this study introduces a novel surface coating strategy for polymethyl-methacrylate (PMMA) using hinokitiol—a natural antibacterial and antifungal compound derived from Hiba. This method enables the formation of a uniform silica–resin layer containing hinokitiol, achieved through a simple immersion process. Using X-ray and neutron reflectivity techniques, we discovered that a uniform silica–resin layer could form on PMMA with significant amounts of hinokitiol present. Time-dependent neutron reflectivity analysis revealed the presence of the following two types of hinokitiol molecules within the silica–resin layer: one type desorbs rapidly with weak capture near the surface, and the other desorbs slowly with strong capture near the PMMA interface, facilitated by hydrogen bonding in the silica–resin nanopores. These findings demonstrate a new mechanism for controlled release of antimicrobial agents from denture surfaces and highlight the potential of this coating technique as a practical and effective strategy for preventing denture-related infections. Full article

(This article belongs to the Special Issue Nanobiocomposite Materials: Synthesis, Properties and Applications)

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18 pages, 3719 KB

Open AccessArticle

Nanostructured Sr-Doped Hydroxyapatite: A Material with Antimicrobial Potential

by Miljana Mirković, Aleksandra Sknepnek, Ana Kalijadis, Aleksandar Krstić, Marija Šuljagić, Marko Perić and Ljubica Andjelković

Nanomaterials 2025, 15(21), 1651; https://doi.org/10.3390/nano15211651 - 29 Oct 2025

Abstract

This research investigated the feasibility of producing strontium-doped nanocrystalline hydroxyapatite (SrHAp) through an environmentally benign synthesis approach and evaluated the antimicrobial activity of the resulting material. The synthesized nanomaterial was subjected to comprehensive characterization. The antimicrobial efficacy of SrHAp was tested against Gram-positive [...] Read more.

This research investigated the feasibility of producing strontium-doped nanocrystalline hydroxyapatite (SrHAp) through an environmentally benign synthesis approach and evaluated the antimicrobial activity of the resulting material. The synthesized nanomaterial was subjected to comprehensive characterization. The antimicrobial efficacy of SrHAp was tested against Gram-positive and Gram-negative bacterial strains. X-ray diffraction (XRD) analysis in combination with Fourier-transform infrared (FT-IR) spectroscopy confirmed the successful formation of pure monocrystalline SrHAp. The scanning electron microscopy (SEM) examination revealed two predominant morphological structures: nanorods and prismatic configurations of the SrHAp. Transmission electron microscopy (TEM) demonstrated that the rod-like SrHAp nanocrystals aggregate into elongated grain structures with a size of about 25 nm × 10 nm. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis confirmed the presence and quantification of the concentrations of calcium, strontium, and phosphorus, while confirming the expected calcium–phosphorus ratio characteristic of hydroxyapatite. The study established that the positive surface charge of the material, with a point of zero charge near pH 10, is essential for its antimicrobial efficiency. These results suggest that SrHAp nanomaterials hold promise for biomedical applications, particularly as antimicrobial coatings for implants and scaffolds for bone tissue, where the prevention of infection is critical. Overall, despite its selective and material quantity-dependent antimicrobial efficacy, environmentally friendly synthesized SrHAp can be successfully applied as an effective controller of targeted microbial contamination, especially of Gram-positive bacterial species S. aureus, L. monocytogenes, S. Enteritidis, and A. baumanii. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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18 pages, 3124 KB

Open AccessArticle

Frequency-Mode Study of Piezoelectric Devices for Non-Invasive Optical Activation

by Armando Josué Piña-Díaz, Leonardo Castillo-Tobar, Donatila Milachay-Montero, Emigdio Chavez-Angel, Roberto Villarroel and José Antonio García-Merino

Nanomaterials 2025, 15(21), 1650; https://doi.org/10.3390/nano15211650 - 29 Oct 2025

Abstract

Piezoelectric materials are fundamental elements in modern science and technology due to their unique ability to convert mechanical and electrical energy bidirectionally. They are widely employed in sensors, actuators, and energy-harvesting systems. In this work, we investigate the behavior of commercial lead zirconate [...] Read more.

Piezoelectric materials are fundamental elements in modern science and technology due to their unique ability to convert mechanical and electrical energy bidirectionally. They are widely employed in sensors, actuators, and energy-harvesting systems. In this work, we investigate the behavior of commercial lead zirconate titanate (PZT) sensors under frequency-mode excitation using a combined approach of impedance spectroscopy and optical interferometry. The impedance spectra reveal distinct resonance–antiresonance features that strongly depend on geometry, while interferometric measurements capture dynamic strain fields through fringe displacement analysis. The strongest deformation occurs near the first kilohertz resonance, directly correlated with the impedance phase, enabling the extraction of an effective piezoelectric constant (~40 pC/N). Moving beyond the linear regime, laser-induced excitation demonstrates optically driven activation of piezoelectric modes, with a frequency-dependent response and nonlinear scaling with optical power, characteristic of coupled pyroelectric–piezoelectric effects. These findings introduce a frequency-mode approach that combines impedance spectroscopy and optical interferometry to simultaneously probe electrical and mechanical responses in a single setup, enabling non-contact, frequency-selective sensing without surface modification or complex optical alignment. Although focused on macroscale ceramic PZTs, the non-contact measurement and activation strategies presented here offer scalable tools for informing the design and analysis of piezoelectric behavior in micro- and nanoscale systems. Such frequency-resolved, optical-access approaches are particularly valuable in the development of next-generation nanosensors, MEMS/NEMS devices, and optoelectronic interfaces where direct electrical probing is challenging or invasive. Full article

(This article belongs to the Special Issue Thermal, Electrical and Thermoelectric Properties of Nanomaterials and Their Applications)

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28 pages, 3927 KB

Open AccessReview

Sustainable Carbon Dots from Cellulose Precursors for Environmental Sensing: Recent Trends and Outlook

by Viviana Bressi, Jihene Belhaj, Rayhane Zribi, Ramzi Khiari and Claudia Espro

Nanomaterials 2025, 15(21), 1649; https://doi.org/10.3390/nano15211649 - 29 Oct 2025

Abstract

Carbon dots (CDs) have emerged as promising nanomaterials for optical sensing due to their outstanding photoluminescence, chemical stability, and biocompatibility. In recent years, the development of sustainable CDs derived from biomass—particularly cellulose—has attracted increasing interest as a green alternative to conventional synthetic routes. [...] Read more.

Carbon dots (CDs) have emerged as promising nanomaterials for optical sensing due to their outstanding photoluminescence, chemical stability, and biocompatibility. In recent years, the development of sustainable CDs derived from biomass—particularly cellulose—has attracted increasing interest as a green alternative to conventional synthetic routes. This review offers a comprehensive overview of recent advances in synthesis, functionalization, and application of cellulose-based carbon dots for environmental sensing. We examine key synthetic approaches—including hydrothermal, microwave-assisted, and pyrolytic methods—and discuss how the structure and origin of cellulose influence the physicochemical properties of the resulting CDs. The mechanisms underlying their sensing performance are analyzed in detail, with a focus on the detection of heavy metals, organic pollutants, and other environmental contaminants. Challenges related to reproducibility, scalability, and long-term stability are critically addressed. Finally, we outline future directions involving hybrid nanomaterials, real-time sensing platforms, and strategies aligned with circular economy principles. This review aims to serve as a valuable resource for researchers in the fields of sustainable nanomaterials, green chemistry, and environmental sensor development. Full article

(This article belongs to the Special Issue Functional Nano-Optoelectronic Devices: From Fundamental Research to Industrial Applications)

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