Eco-friendly Synthesis of N- Cholyl Mercapto Histidine Capped Silver Nanoparticles and its sensing of mercury (II) ions and photo catalytic degradation of Methyl orange.

In this report, we have developed highly water soluble and stable silver nanoparticles (Ag NPs) utilizing N-Cholyl Mercapto Histidine (NCMH) as a reducing and stabilizing agent with near the primary critical micellar concentration (CMC) under ambient sunlight irradiation. Moreover, The NCMH was firstly synthesized by demonstrating the reaction between cholic acid and 2- Mercapto Histidine through a simple acid amine coupling approach. The primary and secondary CMC of NCMH surfactant was measured by pyrene (1× 10-6 M) as a fluorescent probe, and values were found to be 3.2 and 13.1 mM respectively. The synthesised Ag NPs showed at neutral pH and highly stable for more than one year without any noticeable aggregation. The TEM analysis displays the synthesized Ag NPs having a spherical shape and average size of 9.6 ± 0.5 nm. The synthesis of stabilized Ag NPs was used for ultra-sensitive and selective detection of Hg2+ ions in aqueous medium were monitored by Uv-visible spectrometer and naked eyes with a lowest limit of detection (LOD) 7 nM. The photo-catalytic degradation of methyl orange (MO) by utilizing Ag NPs as nano-catalyst exhibits a potential degradation within a study period of 180 min. Concluding that, facile and cost effective green synthesis of NCMH capped Ag NPs possess excellent reducing ability towards the selective detection of Hg2+ ions along with photo-catalytic degradation of MO dye. These true findings detached an innovative pathway of Ag NPs towards the reactivity against the catalytic activity of dye degradation and selective sensing of Hg2+ ions. Thus it paves the way for extensive range of novel potential applications of Ag NPs in various environment friendly approaches of sensitive and analytical protocol in the future.

Correction: Structural, electronic, optical, elastic, thermodynamic and thermal transport properties of Cs2AgInCl6 and Cs2AgSbCl6 double perovskite semiconductors using a first-principles study.

Correction for 'Structural, electronic, optical, elastic, thermodynamic and thermal transport properties of Cs2AgInCl6 and Cs2AgSbCl6 double perovskite semiconductors using a first-principles study' by Keqing Zhang et al., Phys. Chem. Chem. Phys., 2023, 25, 31848-31868, https://doi.org/10.1039/d3cp03795a.

Real-time detection of acetone gas molecules at ppt levels in an air atmosphere using a partially suspended graphene surface acoustic wave skin gas sensor.

To improve the quality of modern life in the current society, low-power, highly sensitive, and reliable healthcare technology is necessary to monitor human health in real-time. In this study, we fabricated partially suspended monolayer graphene surface acoustic wave gas sensors (G-SAWs) with a love-mode wave to effectively detect ppt-level acetone gas molecules at room temperature. The sputtered SiO2 thin film on the surface of a black 36°YX-LiTaO3 (B-LT) substrate acted as a guiding layer, effectively reducing the noise and insertion loss. The G-SAWs exhibited enhanced gas response towards acetone gas molecules (800 ppt) in a real-time atmosphere. The high sensitivity of the G-SAW sensor can be attributed to the elasticity and surface roughness of the SiO2 film. In addition, the G-SAW sensor exhibited rapid response and recovery at room temperature. This study provides a potential strategy for diagnosing different stages of diabetes in the human body.

Structural, electronic, optical, elastic, thermodynamic and thermal transport properties of Cs2AgInCl6 and Cs2AgSbCl6 double perovskite semiconductors using a first-principles study.

In this study, we employ the framework of first-principles density functional theory (DFT) computations to investigate the physical, electrical, bandgap and thermal conductivity of Cs2AgInCl6-CAIC (type I) and Cs2AgSbCl6-CASC (type II) using the GGA-PBE method. CAIC possesses a direct band gap energy of 1.812 eV, while CASC demonstrates an indirect band gap energy of 0.926 eV. The CAIC and CASC exhibit intriguingly reduced thermal conductivity, which can be attributed to the notable reduction in their respective Debye temperatures, measuring 182 K and 135 K, respectively. The Raman active modes computed under ambient conditions have been compared with real-world data, showing excellent agreement. The thermal conductivity values of CAIC and CASC compounds exhibit quantum mechanical characteristics, with values of 0.075 and 0.25 W m-1 K-1, respectively, at 300 K. It is foreseen that these outcomes will generate investigations concerning phosphors and diodes that rely on single emitters, with the aim of advancing lighting and display technologies in the forthcoming generations.

Cost-effective dye-sensitized solar cells based on rutile-phase three-dimensional TiO2 hierarchical nanostructures.

Specifically engineered three-dimensional (3D) and 1D morphologies are expected to play significant roles in the development of next-generation dye-sensitized solar cells. In this study, using a hydrothermal approach without a surfactant or template, we attempted to synthesize a 3D hierarchical rutile titanium dioxide (TiO2 ) architecture by varying the growth temperature and time. X-ray diffraction patterns of the synthesized TiO2 correlated well with rutile TiO2 . Scanning electron microscopy images exhibited different nanostructures, such as nanorods, aggregated nanorods, and 3D TiO2 microflowers comprised of nanorods at 100°C, 130°C, and 160°C, respectively, after growth for 6 h. A significantly improved efficiency was observed for the TiO2 microflowers. The TiO2 microflowers exhibited an efficiency of 1.16%, short-circuit current density of 12.8 mA cm-2 , open-circuit voltage of 0.692 V, and fill factor of 0.67.

Reconfigurable magnon interference by on-chip dynamic wavelength conversion.

Spin waves (SWs), an ultra-low power magnetic excitation in ferro or antiferromagnetic media, have tremendous potential as transport less data carriers for post-CMOS technology using their wave interference properties. The concept of magnon interference originates from optical interference, resulting in a historical taboo of maintaining an identical wavevector for magnon interference-based devices. This makes the attainment of on-chip design reconfigurability challenging owing to the difficulty in phase tuning via external fields. Breaking the taboo, this study explores a novel technique to systematically control magnon interference using asymmetric wavevectors from two different SW modes (magnetostatic surface SWs and backward volume magnetostatic SWs) in a microstructured yttrium iron garnet crossbar. Using this system, we demonstrate phase reconfigurability in the interference pattern by modulating the thermal landscape, modifying the dispersion of the interfering SW modes. Thus, we manifest that such a tunable interference can be used to implement reconfigurable logic gates operating between the XNOR and XOR modes by using symmetric and asymmetric interference, respectively.

Development of Morphologically engineered Flower-like Hafnium-Doped ZnO with Experimental and DFT Validation for Low-Temperature and Ultrasensitive Detection of NOX Gas.

Substitutional doping and different nanostructures of ZnO have rendered it an effective sensor for the detection of volatile organic compounds in real-time atmosphere. However, the low selectivity of ZnO sensors limits their applications. Herein, hafnium (Hf)-doped ZnO (Hf-ZnO) nanostructures are developed by the hydrothermal method for high selectivity of hazardous NOX gas in the atmosphere, substantially portraying the role of doping concentration on the enhancement of structural, optical, and sensing behavior. ZnO microspheres with 5% Hf doping showed excellent sensing and detected 22 parts per billion (ppb) NOX gas in the atmosphere, within 24 s, which is much faster than ZnO (90 s), and rendered superior sensing ability (S = 67) at a low temperature (100 °C) compared to ZnO (S = 40). The sensor revealed exceptional stability under humid air (S = 55 at 70% RH), suggesting a potential of 5% Hf-ZnO as a new stable sensing material. Density functional theory (DFT) and other characterization analyses revealed that the high sensing activity of 5% Hf-ZnO is attributed to the accessibility of more adsorption sites arising due to charge distortion, increased oxygen vacancies concentration, Lewis acid base, porous morphology, small particle size (5 nm), and strong bond interaction amidst NO2 molecule with ZnO-Hf-Ovacancy sites, resulting from the substitution of the host cation (Zn2+) with doping cation (Hf4+).

RF Sputtered Nb-Doped MoS2 Thin Film for Effective Detection of NO2 Gas Molecules: Theoretical and Experimental Studies.

Doping plays a significant role in affecting the physical and chemical properties of two-dimensional (2D) dichalcogenide materials. Controllable doping is one of the major factors in the modification of the electronic and mechanical properties of 2D materials. MoS2 2D materials have gained significant attention in gas sensing owing to their high surface-to-volume ratio. However, low response and recovery time hinder their application in practical gas sensors. Herein, we report the enhanced gas response and recovery of Nb-doped MoS2 gas sensor synthesized through physical vapor deposition (PVD) toward NO2 at different temperatures. The electronic states of MoS2 and Nb-doped MOS2 monolayers grown by PVD were analyzed based on their work functions. Doping with Nb increases the work function of MoS2 and its electronic properties. The Nb-doped MoS2 showed an ultrafast response and recovery time of t rec = 30/85 s toward 5 ppm of NO2 at their optimal operating temperature (100 °C). The experimental results complement the electron difference density functional theory calculation, showing both physisorption and chemisorption of NO2 gas molecules on niobium substitution doping in MoS2.

Design of Graphene Phononic Crystals for Heat Phonon Engineering.

Controlling the heat transport and thermal conductivity through a material is of prime importance for thermoelectric applications. Phononic crystals, which are a nanostructured array of specially designed pores, can suppress heat transportation owing to the phonon wave interference, resulting in bandgap formation in their band structure. To control heat phonon propagation in thermoelectric devices, phononic crystals with a bandgap in the THz regime are desirable. In this study, we carried out simulation on snowflake shaped phononic crystal and obtained several phononic bandgaps in the THz regime, with the highest being at ≈2 THz. The phononic bandgap position and the width of the bandgap were found to be tunable by varying the neck-length of the snowflake structure. A unique bandgap map computed by varying the neck-length continuously provides enormous amounts of information as to the size and position of the phononic bandgap for various pore dimensions. We have also carried out transmission spectrum analysis and found good agreement with the band structure calculations. The pressure map visualized at various frequencies validates the effectiveness of snowflake shaped nano-pores in suppressing the phonons partially or completely, depending on the transmission probabilities.