High-performance UV Research Articles

High-performance Ga2O3-based solar-blind UV photodetectors developed with low fabricating and operating temperature

High-performance Ga2O3-based solar-blind UV photodetectors developed with low fabricating and operating temperature

Si-Implanted β-Ga2O3/CuGaO2 p-n Junction for High-Performance Self-Powered UV Photodetection

Si-Implanted β-Ga2O3/CuGaO2 p-n Junction for High-Performance Self-Powered UV Photodetection

Demonstration of UV-A stimulated emission from optical pumping with a nano-porous cladding layer

Abstract We report room-temperature ultraviolet-A (UV-A) stimulated emission from a multiple-quantum-well laser diode featuring a nano-porous bottom cladding layer on the GaN substrate. For a 1500×15 µm ridge-type edge-emitting laser, we achieved 372.8 nm emission under optical pumping, with a full-width-half-maximum (FWHM) of less than 2 nm and a threshold optical pumping power density less than 1.2 MW/cm2. The integration of a nano-porous cladding layer effectively minimizes lattice mismatch, enhances confinement factor and maintains electrical conductivity. This demonstration expands the potential for developing high-performance UV laser diodes on GaN substrates, overcoming limitations previously imposed by critical thickness contrasts.

Ultraviolet Photodetector Fabrication with Low-Power Dissipation Based on Organic Suboptimal Source-Gated Transistor Architecture and MoO3-Doped Pentacene.

Organic field-effect transistor (OFET)-based photodetectors have been extensively studied owing to their potential applications in various fields, such as imaging, communication, and environmental monitoring. However, the traditional OFET structure brings about high power consumption. Furthermore, their low electrical performance and light sensitivity must be improved to detect harmful UV rays that accelerate skin aging and cause vision degradation. One strategy to fabricate high-performance phototransistors involves the introduction of molybdenum trioxide (MoO3), which serves as a dopant for pentacene, aiming to enhance electrical performance by increasing mobility and decreasing threshold voltage. In addition, the photoreactivity of MoO3 in the UV spectrum is utilized to achieve enhanced light responsivity. In this work, a suboptimal source-gated transistor (sSGT) is introduced instead of a conventional OFET to exploit the work function difference between two electrodes and the active layer to achieve low-power consumption. The power of the sSGT is 1000 times lower than that of the OFET, demonstrating the low-power consumption. The findings indicate the potential fabrication method of high-performance UV phototransistors with low-power consumption induced by incorporating the MoO3 and sSGT structure.

Enhancing luminescence in bio-cellulose derived carbon microcoils through europium incorporation: A pathway to high-performance UV luminophores

Bio-cellulose derived carbon microcoils (BCMC) are renowned for their distinctive helical structure, sustainability, and renewability, making them highly versatile for applications such as microwave absorption, water purification, and energy storage. Despite extensive research on carbon microcoils or nanocoils, the luminescent properties of BCMC remain largely unexplored. This study delves into the luminescence characteristics of BCMC extracted from recycled tea leaves, revealing a broad spectrum of multicolor emissions including ultraviolet (355 nm, 396 nm), blue (467 nm), and near-infrared (764 nm). These emissions are attributed to BCMC's distinctive three-dimensional helical configuration and its rich array of oxygen-containing functional groups. Incorporating europium further tailors the photoluminescent properties of BCMC, significantly amplifying UV and blue light emissions. Additionally, annealing improves UV emission, showcasing the potential for enhanced luminescence performance. This research not only deepens our understanding of sustainable luminescent materials but also paves the way for developing advanced UV luminophores with diverse applications.

Freestanding ZnO Nanowire Films Derived from Carbon Nanotube Template: Implications for High-Performance UV Photodetectors

Freestanding ZnO Nanowire Films Derived from Carbon Nanotube Template: Implications for High-Performance UV Photodetectors

Modern quality control methods of flax seeds herbal drugs in Russia

Flax seeds are valuable medicinal and food raw materials because of their various complex of biologically active substances (BAS). They have a great potential for pharmaceutical practice and food industry. The purpose of the work is to study the possibilities for improvement of methods for standardization of flax seeds and drugs (infusion is the dietary supplement (DS), which contains fatty flax seeds extra virgin oil in gelatin capsule and fatty flax seeds oil containing in multicomponent drugs) on their basis. The following groups of BAS are studied by modern physicochemical methods: contents of polysaccharides (gravimetry), contents and composition of the fatty acids containing in fatty oils (gas flame photometric chromatography) and contents of vitamins B2, C, E, carotenoids (α- and β-carotenoids) (high-performance UV chromatography). The study establishes, that the whole flax seeds contain 8.23±0.38% of polysaccharides, 438±53 mg/g of fatty oils (the main fatty acids are α-linoleic acid (234±47 mg/g), oleic acid (60±12 mg/g), and linoleic acid (61±12 mg/g)), 31.00±4.65 mg/100g of vitamin B2, 330.00±49.50 mg/100g of vitamin C, 19.60±2.94 mg/100g of vitamin E, and 10.30±1.55 mg/100g of carotenoids. Contents of 0.62±0.04% of polysaccharides, 2.85±0.43 µg/100 ml of vitamin B2, and 45.00±6.75 µg/100 ml of vitamin C are peculiar to the infusion. We have determined that the DS “Flax seeds oil in capsules” contents three major fatty acids. They are α-linoleic acid (234±47 mg/g), oleic acid (60±12 mg/g), linoleic acid (61±1 2mg/g), 27.00±4.05 mg/100g of vitamin E (summarized tocopherols in terms of tocopherol acetate), and 14.90±2.24 mg/100g of carotenoids. Contents of fatty oil in the “Dicloran ® Plus” drug is of 277±33 mg/g (the main fatty acids are α-linoleic acid (20±4 mg/g), oleic acid (6±1 mg/g), and linoleic acid (4±1 mg/g)) and 1.10±0.17 µg/100 g of vitamin E. Ratio of major fatty acids containing in the subjects, which consist of fatty flax seeds oils, are: α-linoleic acid: oleic acid: linoleic acid is 4:1:1 is peculiar. The received data is used to update current regulatory documentation and to introduce the new one to regulate quality of flax seeds and flax drugs.

ZnO@NiO core-shell heterojunction photoanode modified with NiOOH co-catalyst for high-performance self-powered photoelectrochemical-type UV photodetector

ZnO, a promising photoanode material, faces significant challenges in achieving high-efficient photoelectrochemical (PEC) type UV photodetectors due to inadequate charge separation and sluggish surface reaction kinetics. Constructing heterojunction nanostructures by coupling of p-NiO to n-ZnO nanowire arrays with well-aligned energy band positions presents a feasible strategy for enhancing PEC-type photodetector performance. Herein, we demonstrate that the designed ZnO@NiO core–shell nanowire arrays form a spatial charge transfer channel, facilitating efficient generation and extraction of charge carriers. The exceptional catalytic properties of NiOOH, derived from the transformation of NiO in an aqueous alkaline environment, serve as a potent co-catalyst, effectively accelerating the kinetics of the surface oxygen evolution reaction. Benefiting from the synergistic effect of the heterojunction and cocatalyst, the optimized photoanode achieves a high responsivity of 438.36 mA/W, a large detectivity of 4.85 × 1012 Jones, and rapid response time of 150.05/150.26 ms, while simultaneously exhibiting long-time PEC stability. This work highlights the critical role of nanostructure design in developing high-performance self-powered UV photodetectors.

Enhanced enantioselective separation of racemic menthol via reverse-phase high-performance liquid chromatography: Method development and computational insights for pre-screening

A robust and efficient enantioselective separation of racemic menthol was achieved on a standard C18 column with reverse-phase high-performance liquid chromatography (RP-HPLC) and UV detector. (R)-α-hydroxy-4-methylbenzeneacetic acid was utilized as the pre-column derivatization reagent. The impact of mobile phase composition on diastereomer selectivity was thoroughly investigated, resulting in a high resolution of 2.11 under optimized conditions. The method was rigorously validated for linearity, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ). Notably, a separation pre-screening mechanism (SPM) and a prediction model was developed based on density functional theory (DFT) studies. This model elucidated the relationship between molecular polarity differences (△MPI) and chromatographic behavior, facilitating the interpretation and prediction of racemic menthol resolution with various chiral derivatization reagents. The present work not only presents an efficient and economical approach for menthol enantiomeric separation, but also offers valuable insights for the innovative design and advancement of chromatographic methodologies for a wide array of chiral enantiomers.

High-responsivity photoelectrochemical ultraviolet photodetector based on SnO2 nanosheets-Ga2O3

Abstract Tin oxide (SnO2) has garnered significant attention for its high spectral selectivity when used as an ultraviolet photodetector. In this study, SnO2 nanosheets (NSs) were synthesized via a hydrothermal method, followed by spin-coating a layer of Ga2O3 thin film to construct a heterojunction photoelectrochemical ultraviolet photodetector (PEC UV PD). Initially, we investigated the effect of precursor composition on the properties of the Ga2O3 thin films. It was observed that the thickness of the films increased with higher precursor concentrations, while the optical bandgap decreased. Based on these findings, we successfully fabricated the SnO2 NSs-Ga2O3 PEC UV PD. Electrochemical analysis revealed that as the precursor concentration used for spin-coating Ga2O3 increased, the device's responsivity and detectivity initially increased and then decreased. After optimization, the device prepared with a 0.2M Ga(NO3)3 solution spin-coated on SnO2 exhibited excellent spectral selectivity (R 265nm/R 420nm ~ 4472), a responsivity of 4.86 mA W-1, and a detectivity of 2.72×109 Jones. This study demonstrates that coating Ga2O3 is an effective approach to constructing high-performance SnO2-based UV PDs.

Enhanced UV photodetector using Mg-doped ZnO sub-micro tube films synthesized through laser-assisted chemical bath growth

This study presents the fabrication of MgxZn(100-X)O thin films (TFs) with Mg concentration levels (x) of 0.5 at%, 1.0 at%, 1.5 at%, and 2.0 at% on glass substrates using the novel laser-assisted chemical bath growth (LACBG) method, aimed at investigating their photo-response for potential UV photodetector applications. Utilizing a continuous wave semiconductor laser with a 444.5 nm wavelength, 1 W power, and 6 min of irradiation, the LACBG method successfully produced high-quality Mg-doped ZnO TFs. These films were deposited on glass substrates coated with silver (Ag) to serve as electrode contacts for constructing a metal-semiconductor-metal (MSM) UV photodetector. The structural, optical, and electrical properties of the TFs were thoroughly analyzed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to examine the crystal microstructures and surface morphologies, revealing vertically aligned hexagonal symmetrical sub-micro tubes. In contrast, energy dispersive X-ray (EDX) analysis confirmed successful Mg incorporation into the ZnO lattice. UV–visible absorbance spectra indicated a blue shift in the absorption edge and increased band gap energy from 3.24 eV to 3.67 eV with rising Mg content. The UV photodetectors, particularly those with 2.0 at% Mg-doped ZnO TFs, demonstrated significantly enhanced UV responsiveness attributed to optical confinement, high surface-to-volume ratio, and superior structural quality. Performance metrics for the 2.0 at% Mg-doped ZnO TFs included a responsivity of 10.60 A/W, external quantum efficiency of 34.10, specific detectivity of 2.25 × 107 Jones, noise equivalent power of 5.34 × 10−11 W, rise time of 86.9 ms, and decay time of 324.4 ms. These findings underscore the potential of Mg-doped ZnO TFs for high-performance UV photodetection applications. The novelty of this study lies in utilizing LACBG to achieve high-quality Mg-doped ZnO TFs, offering a cost-effective, low-temperature method that enhances UV photodetector performance.

Enantioselective Binding of Proton Pump Inhibitors to Alpha1-Acid Glycoprotein and Human Serum Albumin-A Chromatographic, Spectroscopic, and In Silico Study.

The enantioselective binding of three proton pump inhibitors (PPIs)-omeprazole, rabeprazole, and lansoprazole-to two key plasma proteins, α1-acid glycoprotein (AGP) and human serum albumin (HSA), was characterized. The interactions between PPI enantiomers and proteins were investigated using a multifaceted analytical approach, including high-performance liquid chromatography (HPLC), fluorescence and UV spectroscopy, as well as in silico molecular docking. HPLC analysis demonstrated that all three PPIs exhibited enantioseparation on an AGP-based chiral stationary phase, suggesting stereoselective binding to AGP, while only lansoprazole showed enantioselective binding on the HSA-based column. Quantitatively, the S-enantiomers of omeprazole and rabeprazole showed higher binding affinity to AGP, while the R-enantiomer of lansoprazole displayed greater affinity for AGP, with a reversal in the elution order observed between the two protein-based columns. Protein binding percentages, calculated via HPLC, were greater than 88% for each enantiomer across both transport proteins, with all enantiomers displaying higher affinity for AGP compared to HSA. Thermodynamic analysis indicated that on the HSA, the more common, enthalpy-controlled enantioseparation was found, while in contrast, on the AGP, entropy-controlled enantioseparation was observed. The study also identified limitations in using fluorescence titration due to the high native fluorescence of the compounds, whereas UV titration was effective for both proteins. The determined logK values were in the range of 4.47-4.83 for AGP and 4.02-4.66 for HSA. Molecular docking supported the experimental findings by revealing the atomic interactions driving the binding process, with the predicted enantiomer elution orders aligning with experimental data. The comprehensive use of these analytical methods provides detailed insights into the enantioselective binding properties of PPIs, contributing to the understanding of their pharmacokinetic differences and aiding in the development of more effective therapeutic strategies.

Self-powered high performance UV photodetectors based on spin coated n-ZnO/p-Si heterostructure

Self-powered photodetectors with high responsivity and external quantum efficiency (EQE) are in great demand for various practical applications. This paper reports the fabrication and evaluation of self-powered, high-performing ultraviolet photodetectors with fast switching action. A p-n junction was formed by spin coating n-type ZnO on p-silicon substrates. The photodetector showed a responsivity of 0.15 A/W and an EQE of 52 %. The switching speed of devices was as low as 250 ms, even under zero bias. XRD analysis revealed the hexagonal wurtzite structure and AFM images confirmed the good quality of the films with roughness values as low as 2 nm. Defect analysis was done by photoluminescence studies. The molarity of the precursor solution and the annealing temperature were varied to optimize the performance. Sample with molarity 0.5 M annealed at 500 °C showed the best results.

High-performance solar-blind UV bipolar junction phototransistor based on a vertical Pt/Ga2O3/p-Si Schottky emitter structure

Solar-blind UV photodetectors are extensively applied in both military and civilian domains. In this work, a high-performance Pt/Ga2O3/p-Si Schottky emitter solar-blind UV bipolar junction phototransistor is demonstrated. It exhibits a peak responsivity (@246 nm) of 1632.8 A/W under a bias of 5 V. This responsivity is significantly enhanced compared to the Al/Ga2O3/p-Si heterojunction photodetector, while its response speed remains largely unchanged. Additionally, the device demonstrates excellent solar-blind UV spectral selectivity, with a solar-blind UV to visible-blind UV rejection ratio (R246 nm/R365 nm) reaching 2.4×104. This work provides new insights into the design and fabrication of high-performance Ga2O3-based solar-blind UV photodetectors.

Boosting deep-ultraviolet photodetector performance via ferroelectric effect based on HfAlOx@PEI composite

In this study, hafnium-aluminum oxide (HfAlOx) was used as an effective active layer in a self-powered deep-ultraviolet (UV) photodetector. For the first time, we exploited the ferroelectric properties of crystalline HfAlOx to enhance device performance. The HfAlOx powder obtained at an annealing temperature of 850 °C exhibited the highest-intensity peak for the orthorhombic phase (o-phase), representing the ferroelectric property of the material. The HfAlOx particles were reduced to a small size using mechanical treatment to facilitate the preparation of a composite thin film with a polyethyleneimine (PEI) polymer matrix. First, the HfAlOx@PEI composite film-based photodetector demonstrated a remarkable on/off ratio of more than 103 and a rapid response (trise/tfall of 0.127/2.7 s) at zero bias under 254-nm UV illumination. Second, the photocurrent of the device was dramatically boosted under an external bias owing to the injection of carriers, supported by the ferroelectric effect of the o-phase HfAlOx. As a result, the external quantum efficiency and responsivity approached 2628 % and 5.37 A/W at −1 V bias, respectively. Furthermore, the device exhibited excellent photostability, demonstrating almost no change in the photocurrent after 1000 s of UVC irradiation. Our findings provide guidance for the preparation of optoelectronic devices, particularly self-powered high-performance UV photodetectors.

Nanoparticle-Mediated remediation of wastewater contaminants: An inclusive analysis of glyphosate, Congo red and methyl orange

New techniques in purification are called for because, currently pollutants found within the wastewater sources are known to have adverse effects of man health, agricultural productivity and industrial applications. The purpose of this research was to assess the efficiency of different synthesized NPs in the rteutal of glyphosate, Congo red and MO from aqueous solution using a glass column. To determine the concentration of these contaminants, two analytical techniques namely High-Performance Liquid Chromatography (HPLC) and UV–Visible spectrophotometry were used. The findings revealed that the community removal rates differed depending on nanoparticle type, treatment time and light intensity. Zinc oxide nanoparticles (ZONPs) were found to reduce the glyphosate concentration by 56.81 % under 100-watt light after 120 minutes. Iron oxide nanoparticles (IONPs) on the other hand were found to eliminate 62.63 % of glyphosate without the application of light for the same length of time, this figure rose to 87 % when 100-watt light was applied. ZONPs also decolourized 59 % Congo red after 4 h and the decolorization efficiency increased to 86 % when exposed to 30 watt light. Further, magnetic iron oxide nanoparticles (MIONPs) reduced MO by 23.81 % under 100-watt light for 120 minutes. This research demonstrates that NPs may have a future in regard to water treatment as agents which are efficient to high degree; and in part, the ZONPs are more effective in elimination of glyphosate while the IONPs may be better suited for the removal of Congo red. The evidence suggest that more attention should be paid to the characteristic of NPs, the treatment time, and the light intensity in case of employing the technology in water treatment.

Inorganic Semiconductor-Based Flexible UV Photodetector Arrays Achieved by Specific Flip-Chip Bonding.

In recent years, flexible UV photodetectors (PDs) with complex environmental adaptability and great wearability have attracted the attention of researchers worldwide. Wide bandgap inorganic semiconductor materials with excellent optoelectronic properties and mechanical stability are key functional materials for UV PD devices. However, the high temperature processing and inherent brittleness limit the further application of high-quality inorganic semiconductors in the field of flexible optoelectronics. In this work, we develop a specific flip-chip bonding fabrication technique that utilizes high-temperature treated inorganic semiconductor materials for high-performance flexible UV detection devices. Leveraging this technique, a 7 × 7 pixel flexible UV photodetector array (UV-FPDA) device based on a vertical architecture Mg-doped ZnO/NiO (Mg:ZnO/NiO) heterojunction transistor is built. The UV-FPDAs exhibit a high responsivity of 75.8 A/W and an outstanding detectivity of 8.5 × 1012 Jones. Besides, the UV-FPDAs also demonstrate excellent bending stability. Furthermore, the photoresponse characteristics of each pixel are trained and learned by an artificial neural network to achieve clear imaging of UV light information. Our results provide a new pathway for the application of inorganic semiconductors in the field of high-performance flexible UV photodetection.

One-Dimensional ZnO Nanorod Array Grown on Ag Nanowire Mesh/ZnO Composite Seed Layer for H2 Gas Sensing and UV Detection Applications.

Photodetectors and gas sensors are vital in modern technology, spanning from environmental monitoring to biomedical diagnostics. This paper explores the UV detection and gas sensing properties of a zinc oxide (ZnO) nanorod array (ZNA) grown on silver nanowire mesh (AgNM) using a hydrothermal method. We examined the impact of different zinc acetate precursor concentrations on their properties. Results show the AgNM forms a network with high transparency (79%) and low sheet resistance (7.23 Ω/□). A sol-gel ZnO thin film was coated on this mesh, providing a seed layer with a hexagonal wurtzite structure. Increasing the precursor concentration alters the diameter, length, and area density of ZNAs, affecting their performance. The ZNA-AgNM-based photodetector shows enhanced dark current and photocurrent with increasing precursor concentration, achieving a maximum photoresponsivity of 114 A/W at 374 nm and a detectivity of 6.37 × 1014 Jones at 0.05 M zinc acetate. For gas sensing, the resistance of ZNA-AgNM-based sensors decreases with temperature, with the best hydrogen response (2.71) at 300 °C and 0.04 M precursor concentration. These findings highlight the potential of ZNA-AgNM for high-performance UV photodetectors and hydrogen gas sensors, offering an alternative way for the development of future sensing devices with enhanced performance and functionality.

Enhanced ultraviolet photodetection with Ag nanoparticle-decorated ZnO nanowires and core-shell electrodes

Our study presents the synthesis and characterization of one-dimensional (1-D) zinc oxide (ZnO) nanorod (NR) arrays via low-temperature hydrothermal synthesis, followed by surface modification with silver nanoparticles (Ag NPs). Silver nanowires (AgNWs) are potential alternatives to indium-tin oxide, but their poor stability in atmospheric conditions poses a challenge. To address this, we developed ultrathin Ag/ZnO core-shell structured nanowire networks for ultraviolet-photodetectors (UV-PDs). This cost-effective solution process yielded high transmission (77 %) and low sheet resistance (8.3 Ω/sq). We comprehensively investigated surface morphology, crystalline nature, elemental composition, optical properties, and electrical performance of both synthesized nanorod arrays and NW networks. The UV photodetector exhibited a rise time of approximately 1.35 s and a decay time of 8.01 s, both faster than pristine AgNW electrodes. Additionally, the dark current decreased from 9 nA to 3.5 nA after incorporating Ag/ZnO, accompanied by a significant improvement in photocurrent. These results highlight a promising approach for high-performance UV photodetectors, leveraging the stability and conductivity of Ag/ZnO core-shell NW networks.

High-Performance UV–Visible Broad Spectral Phototransistors Based on CuPc/Cs3Bi2I9 Heterojunction

High-Performance UV–Visible Broad Spectral Phototransistors Based on CuPc/Cs3Bi2I9 Heterojunction