As device miniaturization approaches its physical limits, the performance enhancement of silicon electronics has become increasingly difficult, shifting attention toward 2D semiconductors as potential alternatives. Among these, monolayer platinum diselenide (PtSe2) has garnered significant interest as a next-generation channel material for nanoelectronics. Distinguished by its exceptional theoretical carrier mobility-six times higher than that of MoS2-and remarkable air stability, monolayer PtSe2 emerges as a promising candidate for advanced semiconductor applications. However, achieving uniform growth of high-quality monolayer PtSe2 presents challenges. In this study, we report the first successful growth of high-quality monolayer PtSe2 films using an optimized metal-organic chemical vapor deposition (MOCVD) process. We confirmed the uniform growth of the monolayer films over an area of 1.5 cm × 1.5 cm through various optical analyses, proving superior controllability of precursor flow and growth rate. Oxygen was introduced during the growth process to effectively eliminate carbon impurities, resulting in a high-quality film. Finally, we demonstrated an array-level transistor employing the monolayer PtSe2 as the channel, achieving low off-current and a maximum ION/IOFF ratio of 8.31 × 104. We succeeded in growing an industrially applicable level of semiconducting PtSe2 film, thereby highlighting the advantages of our growth method for future electronic applications.

We present a broadband photodetector based on Bi2Se3 nanosheets, demonstrating stable room-temperature photodetection extending up to 4000 nm. Such MWIR response is enabled by the selenization of solution-processed Bi2S3 nanosheets into Bi2Se3 nanosheets. Furthermore, owing to the chemically stable Bi3+-chalcogen framework of Bi2S3, selective sulfur-to-selenium substitution proceeds via controlled anion exchange without disrupting the bismuth sublattice, resulting in a phase reconstruction that preserves the original morphology. This Bi2S3-based conversion effectively suppresses defect formation and mitigates reproducibility issues commonly associated with direct Bi2Se3 growth, while simultaneously alleviating the substrate-dependent limitations of conventional chemical vapor deposition (CVD). The converted Bi2Se3-based photodetectors exhibit a broadband photoresponse spanning from the visible to the MWIR region, with reliable operation confirmed by linear power-dependent photocurrent, repeatable switching behavior, and long-term durability. To facilitate practical applications, including device miniaturization, the unique optoelectronic properties of single Bi2Se3 nanosheets were further investigated. We fabricated a photodetector by depositing electrodes on the anodes of a single Bi2Se3 nanosheet using a maskless lithography process. This single nanosheet device exhibits remarkable photoresponse from the visible to the near-infrared, particularly achieving a responsivity (R) of 51.4 A/W, a detectivity (D*) of 2.41 × 1011 Jones, and an external quantum efficiency (EQE) of 6500% under near-infrared (NIR) excitation. These results demonstrate the effective preparation of Bi2Se3 materials with broadband and stable photodetection capabilities, demonstrating their strong potential for application in next-generation optoelectronic devices.

2D Ti3C2Tx MXene offers high electrical conductivity and a large surface area, making it attractive for electrocatalysis. However, its intrinsic hydrogen evolution reaction (HER) activity remains poor due to the lack of active catalytic sites. To activate the otherwise inert surface, platinum monosulfide (PtS) nanoparticles are synthesized directly on Ti3C2Tx nanosheets via thermal decomposition of a single‐source precursor, Pt(dmampS)2, in a solution‐based process. This direct growth strategy enables uniform dispersion of PtS nanoparticles and intimate interfacial contact with the MXene surface, without the need for binders or surfactants. The resulting PtS/Ti3C2Tx heterostructure exhibits significantly enhanced HER performance, achieving a low overpotential of −104 mV at a current density of −10 mA cm−2 and a Tafel slope of 48.3 mV dec−1.

The synthesis, characterization, and vapor-phase growth of volatile Cr-(III) complexes as single-source precursors for Cr2O3 thin films are reported. A series of Cr complexesCr-(mdpa)3 (mdpa = N-methoxy-2,2-dimethylpropanamide) (1), Cr-(edpa)3 (edpa = N-ethoxy-2,2-dimethylpropanamide) (2), Cr-(empa)3 (empa = N-ethoxy-2-methylpropanamide) (3), and Cr-(mpa)3 (mpa = N-methoxypropanamide) (4)were synthesized via salt elimination reactions between CrCl3·3THF and N-alkoxy carboxamidate salts. These complexes were characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis (TGA), single-crystal X-ray diffraction (SC-XRD), Hirshfeld surface analysis, powder X-ray diffraction (PXRD), and vapor pressure measurement. The crystal structure of complex 1 revealed a distorted octahedral geometry with a κ2 (O,O) binding mode. TGA demonstrated that complex 1 underwent weight loss at 132 °C and no residue remained at 500 °C. The enthalpy of vaporization of 1 was estimated to be 25.58 kJ/mol, making it an optimal precursor for Cr2O3 thin films. The XRD patterns of Cr2O3 films deposited on SiO2/Si substrates confirmed their crystalline nature, showing prominent peaks at 2θ = 33.5° and 41.5°. In addition, X-ray photoelectron spectroscopy validated the target Cr/O ratio, supporting the successful formation of Cr2O3 films.

In this study, we devised an innovative cartridge-type modular photodetector designed to boost the photoresponse of two-dimensional (2D) materials by utilizing up-conversion particles (UCPs) in selective infrared (IR) regions beyond the bandgap. The merit of this structure is that the incident near-infrared or short wave infrared (SWIR) light, after passing through the 2D SnSe channel layer, is converted into visible light via the up-conversion effect and then reabsorbed by SnSe. To further optimize the photoresponse improvement in the SWIR region, we fine-tuned the dopant material and its concentration for the UCPs, attaining a 3.28-fold enhancement in the up-conversion efficiency. Using these approaches, we accomplished a 9.74-fold enhancement in the selective photoresponse within the SWIR region of 2D SnSe. We extended this approach to a 2D MoS2/UCP system to demonstrate the broad applicability of a cartridge-type modular photodetector design using 2D materials and UCPs for broadband photodetection. Additionally, we demonstrated a method for reusing a cartridge-type modular photodetector by recovering the UCP and quartz framework and removing the device components for repeated use.

A sulfur-assisted one-pot strategy is developed to synthesize ultrathin bismuth sulfide (Bi2S3) nanosheets, enabling high-performance flexible photodetectors. By tuning the sulfur content, the resulting morphology can be controlled to yield either bulk structures or nanosheets. The synthesized Bi2S3 nanosheets exhibit a uniform thickness of ≈86 nm and a narrow bandgap of 1.24 eV, enabling broadband light absorption from the ultraviolet (UV) to the infrared (IR) regions. A flexible photodetector is fabricated by uniformly spray-coating the Bi2S3 dispersion onto a PDMS substrate. Under 980 nm Near-IR (NIR) illumination, the device demonstrates a photocurrent of 61.2 µA, a responsivity (R) of 0.95 A W-1, a detectivity (D*) of 1.4 × 1012 Jones, and an external quantum efficiency (EQE) of 120%. The device also exhibits excellent operational stability, maintaining its initial photocurrent over 650 illumination cycles. It maintains 92% of its photocurrent under bending radii of 12, 10, and 8 mm, and retains ≈90% of its original performance after 20 000 bending cycles at a radius of 8 mm. These results demonstrate that morphology-controlled Bi2S3 nanosheets effectively mitigate brittleness, providing both enhanced mechanical flexibility and reliable photodetection performance.

In this study, we developed a highly sensitive and selective gas sensor utilizing an In2O3/MXene-based nano-composite, which operates effectively at room temperature under UV irradiation. The incorporation of UV light enhances gas adsorption and desorption kinetics, resulting in a rapid and reversible resistance change upon NO2 exposure. Unlike conventional metal oxide-based gas sensors that require high-temperature operation (typically above 200 degrees C), our sensor demonstrates excellent photo-activated gas sensing capabilities at room temperature, significantly reducing power consumption and enhancing practical applicability. As a flexible sensor, it maintains mechanical robustness even after being bent more than 2000 times in application, and ensures long-term stability against external stress for more than 30 days. It has also been shown to maintain high selectivity for NO2 even in the presence of common interfering gases such as NH3, CO, SO2, and ethanol, which are commonly encountered in industrial and urban environments, and has been proven to maintain excellent gas detection performance even under harsh conditions such as high humidity (70 % RH) and direct water exposure. Excellent gas response with linearity was observed in the 5-100 ppb NO2 range, and the limit of detection (LOD) was calculated to be 0.79 ppb, indicating ultra-sensitive detection performance suitable for real-world air quality monitoring.

Nickel monosulfide (NiS) is a promising material in electrochemical energy conversion and storage owing to its high conductivity, chemical stability, and cost-effectiveness. However, achieving high-quality, phase-pure, and homogeneous NiS thin films remains challenging. In this study, we synthesized phase-pure beta-NiS films on silicon dioxide/silicon substrates using the single-source precursor bis(N,N-dimethylamino-2-methylpropane-2-thiolato) nickel(II) (Ni(dmampS)2) via metal organic chemical vapor deposition (MOCVD). The unique distorted squareplanar structure of Ni(dmampS)2 facilitates favorable interactions with the substrate surface, enhancing adsorption and enabling uniform film growth at relatively low temperatures. Consequently, we obtained highly crystalline films with minimal secondary phases or impurities. Electrochemical measurements further demonstrated that beta-NiS films exhibit excellent catalytic activity and stability for the hydrogen evolution reaction under acidic conditions. This study highlights the potential of single-source precursor MOCVD as a scalable method for producing high-quality beta-NiS thin films.

A topological crystalline insulator (TCI) constitutes a valid candidate for optoelectronic applications owing to its broad spectral absorption, ultrafast response, and excellent stability. Thus far, the upscaling of the synthetic approach for TCIs has not been accomplished. Here, we proposed the one-step upscaling of a 6 in. two-dimensional (2D) SnSe0.9Te0.1 TCI for highly robust broadband photodetection from visible to LWIR. The photoresponsivity and detectivity of the SnSe0.9Te0.1-based photodetector corresponded to 3.34 A W-1 and 3.1 × 1011 Jones for 532 nm, 11.17 A W-1 and 1.07 × 1012 Jones for 1064 nm, 0.01 A W-1 and 1.03 × 1010 Jones for 1550 nm, and 0.002 A W-1 and 5.36 × 108 Jones for 4000 nm, respectively. In addition, the evident photoresponse was perceived by the subtle thermal radiation of human fingers. We systematically evaluated the performance reliability and multienvironmental stability of the SnSe0.9Te0.1-based photodetector under various conditions, including prolonged air exposure, thermal stress, humidity, and water immersion. We proposed a topological electronic structure of SnSe0.9Te0.1 by the atomic substitution of Te into orthorhombic SnSe, permitting the rock-salt phase transition in a localized area, resulting in highly robust broadband photodetection.

Practical optoelectronic application of 2D Pt dichalcogenides faces two crucial challenges: establishing a reliable synthetic route and developing a pertinent patterning technique. A streamlined strategy is proposed for site-specific and size-tunable synthesis of Pt dichalcogenides, achieved by pre-defining of Pt templates via focused ion beam (FIB) combined with selenization or tellurization without requiring lithography processes. The synthetic conditions are optimized by altering reaction temperature, time, and thickness of Pt templates, as verified by comprehensive spectro-microscopic analysis. The universal applicability of streamlined site-specific synthesis for Pt dichalcogenides is ascertained, highlighting its potential for visible and NIR photodetection. The PtSe2-based photodetector exhibits maximized photocurrents of 134 mu A at 532 nm and 178 mu A at 980 nm, whereas the PtTe2-based device demonstrates enhanced values of 231 and 382 mu A at the respective wavelengths. This approach corroborates an innovative route to resolve prerequisites associated with establishing a reliable synthetic route and developing a pertinent patterning technique.

Molybdenum disulfide (MoS2) has recently emerged as a promising material for the development of triboelectric nanogenerators (TENGs) owing to its inherently negative triboelectric properties when paired with polymeric layers, along with its notable transparency and mechanical flexibility. However, MoS2-based TENGs operating in the contact-separation mode encounter critical limitations, including mechanical wear and limited triboelectric performance, particularly within the constraints of conventional 2D geometries. This paper reports the novel one-step laser-assisted synthesis of hemispherical MoS2 through the controlled nucleation and growth of MoS2 precursor seeds. The hemispherical structures synthesized at the optimized precursor concentration (0.32 m) exhibit a mean diameter of 234.4 nm with a standard deviation of 30.4 nm, uniformly distributed across a wafer-scale substrate. Hemispherical MoS2 significantly increases the electric-field concentration, making it well-suited for integration into noncontact-mode TENG (NC-TENG) devices. Compared with a flat MoS2-based NC-TENG, a hemispherical MoS2-based NC-TENG demonstrates a 22-fold increase in average capacitance (≈112 pF, Dvertical = 2 mm) and a 37-fold increase in open-circuit voltage (≈2.25 V, Dvertical = 2 mm), while extending the operational distance to 10 mm. Furthermore, this advanced hemispherical MoS2 architecture is employed to fabricate a self-powered image sensor array, underscoring its potential for broader applications.

This paper reports chemiresistive multiarray gas sensors through the synthesized ternary nanocomposites, using a one-pot method to integrate two-dimensional MXene (Ti3C2Tx) with Ti-doped WO3 (Ti-WO3/Ti3C2Tx) and Ti3C2Tx with Pd-doped SnO2 (Pd-SnO2/Ti3C2Tx). The gas sensors based on Ti-WO3/Ti3C2Tx and Pd-SnO2/Ti3C2Tx exhibit exceptional sensitivity, particularly in detecting 70% at 1 ppm acetone and 91.1% at 1 ppm of H2S. Notably, our sensors demonstrate a remarkable sensing performance in the low-ppb range for acetone and H2S. Specifically, the Ti-WO3/Ti3C2Tx sensor demonstrates a detection limit of 0.035 ppb for acetone, and the Pd-SnO2/Ti3C2Tx sensor shows 0.116 ppb for H2S. Simultaneous measurements with Ti-WO3/Ti3C2Tx- and Pd-SnO2/Ti3C2Tx-based sensors enable the evaluation of both the concentration and type of unknown target gases, such as acetone or H2S. Furthermore, density functional theory calculations are performed to clarify the role of Ti and Pd doping in enhancing the performance of Ti-WO3/Ti3C2Tx and Pd-SnO2/Ti3C2Tx nanocomposites. Theoretical simulations contribute to a deeper understanding of the doping effects, providing essential insights into the mechanisms underlying the enhanced gas response of the gas sensors. Overall, this work provides valuable insights into the gas-sensing mechanisms and introduces a novel approach for high-performance multiarray gas sensing.

In this study, we developed an H2S gas sensor based on a MXene/MoS2 heterostructure, using the Langmuir-Blodgett (LB) technique and chemical vapor deposition (CVD). Ti3C2T x MXene nanosheets were uniformly transferred onto SiO2/Si substrates via the LB technique, achieving near-complete coverage. Subsequently, flower-like MoS2 was grown on the MXene-coated substrate through CVD, with vertical growth observed on the MXene layers. Our hybrid sensors exhibited a significant enhancement in gas response, with the MXene/MoS2 heterostructure showing a response of 0.5 to H2S - approximately five times greater than that of pristine MXene. This improvement is attributed to the formation of a heterojunction, which increases electron mobility and reduces the depletion layer, enabling more efficient gas detection. Furthermore, the sensor demonstrated excellent selectivity for H2S over other gases, including H2, NO2, NH3, NO, and VOCs. The combination of the LB technique and CVD not only enhances gas sensor performance but also offers a promising strategy for synthesizing materials for various electrochemical applications.

AbstractA promising flexible photodetector based on hybrid nanocomposites of 2D MXene and In2O3 nanoparticles (NPs) has been developed, demonstrating excellent ultraviolet (UV) light responsivity. In this work, In2O3‐decorated MXene nanosheets (In2O3MX) are synthesized via a simple one‐step sonochemical method using ultrasonication, rapidly producing the composites in a short time. The synthesized material shows efficacy across broadband wavelengths (UV, Vis, NIR). Notably, the photodetector using In2O3MX exhibits a responsivity (R) of 121.6 A W−1 and a specific detectivity (D*) of 106.4 × 10¹⁰ Jones in the UV range, and confirming enhanced electrical properties and the feasibility of low‐voltage detection with tau plots. Additionally, the electrical and optical characteristics remain unchanged after bending the device up to 10,000 times with a bending radius of 6.0 mm, highlighting its suitability for flexible optoelectronic applications. Overall, this study introduces a novel approach to the simple synthesis of 2D MXene nanocomposites and provides valuable insights into the development of flexible photodetectors using these materials.

Despite the advancement of the Internet of Things (IoT) and portable devices, the development of zero-biased sensing systems for the dual detection of light and gases remains a challenge. As an emerging technology, direct energy conversion driven by intriguing physical properties of two-dimensional (2D) materials can be realized in nanodevices or a zero-biased integrated system. In this study, we unprecedentedly attempted to exploit the photostimulated pyrothermoelectric coupling of two-dimensional SnSe for use in zero-biased multimodal transducers for the dual detection of light and gases. We synthesized homogeneous, large-area 6 in SnSe multilayers via a rational synthetic route based on the thermal decomposition of a solution-processed single-source precursor. Zero-biased SnSe transducers for the dual monitoring of light and gases were realized by exploiting the synergistic coupling of the photostimulated pyroelectric and thermoelectric effects of SnSe. The extracted photoresponsivity at 532 nm and NO2 gas responsivity of the SnSe-based transducers corresponded to 1.07 x 10(-6) A/W and 13263.6% at 0 V, respectively. To bring universal applicability of the zero-biased SnSe transducers, the wide operation bandwidth photoelectrical properties (visible to NIR) and dynamic current responses toward two NO2/NH3 gases were systematically evaluated.

Thermoelectric materials play a crucial role in converting heat into electricity, offering significant potential for applications in waste heat recovery and cooling. Herein, an innovative approach that combines an organic–inorganic hybrid superlattice structure with nanocrystal‐amorphous composite nanolayers is introduced. The nanocrystal‐amorphous composite enhances the Seebeck coefficient resulting in a notable twofold improvement in the power factor. The superlattice, alternating self‐assembled organic monolayers and inorganic nanolayers, effectively reduces lattice thermal conductivity by creating multiple interfaces that scatter phonons effectively. The integration of the nanocrystal‐amorphous composite nanolayers into the superlattice provides a dual advantage, simultaneously boosting the power factor and suppressing thermal conductivity. This synergistic effect leads to exceptional thermoelectric performance in the 4‐mercaptophenol/Sb2Te3 superlattice, with achieved figure of merit (ZT) values of 3.48 at 300 K and reaching a peak ZT value exceeding 4.0 at 400 K while surpassing 2.5 over the temperature range from 300 to 500 K. These results suggest that this innovative approach paves the way for the development of highly efficient thermoelectric materials, propelling efforts toward more energy‐efficient and environmentally friendly solutions.

Portable and personalized artificial intelligence (AI)-driven sensors mimicking human olfactory and gustatory systems have immense potential for the large-scale deployment and autonomous monitoring systems of Internet of Things (IoT) devices. In this study, an artificial Q-grader comprising surface-engineered zinc oxide (ZnO) thin films is developed as the artificial nose, tongue, and AI-based statistical data analysis as the artificial brain for identifying both aroma and flavor chemicals in coffee beans. A poly(vinylidene fluoride-co-hexafluoropropylene)/ZnO thin film transistor (TFT)-based liquid sensor is the artificial tongue, and an Au, Ag, or Pd nanoparticles/ZnO nanohybrid gas sensor is the artificial nose. In order to classify the flavor of coffee beans (acetic acid (sourness), ethyl butyrate and 2-furanmethanol (sweetness), caffeine (bitterness)) and the origin of coffee beans (Papua New Guinea, Brazil, Ethiopia, and Colombia-decaffeine), rational combination of TFT transfer and dynamic response curves capture the liquids and gases-dependent electrical transport behavior and principal component analysis (PCA)-assisted machine learning (ML) is implemented. A PCA-assisted ML model distinguished the four target flavors with >92% prediction accuracy. ML-based regression model predicts the flavor chemical concentrations with >99% accuracy. Also, the classification model successfully distinguished four different types of coffee-bean with 100% accuracy.