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Background: It is imperative to enhance the quality of sprouts since they are a rich source of various primary and secondary metabolites. The objective of this work was to examine how multiwalled carbon nanotubes (MWCNTs) priming at various concentrations affected the nutritional qualities of four horticultural plants (T. foenum-graecum, L. grandiflorum, L. sativum and A. graveolens) and their sprouting processes., Results: Among the four applied concentrations (10-60 mgL -1 ), MWCNTs at 10 and 40 mg L⁻¹ induced the highest biomass accumulation in L. grandiflorum and T. foenum-graecum, respectively, while 60 mg L⁻¹ was most effective for L. sativum and A. graveolent. MWCNTs induced growth by enhancing photosynthesis, as shown by increased chlorophyll content and rubisco activity, which rose by 27%, 17%, 23% and 12% in T. foenum-graecum, L. grandiflorum, L. sativum, and A. graveolens, respectively. Enhanced photosynthesis by MWCNTs improved sugar metabolism as indicated by increased activity of sugar metabolic enzymes such as amylase, starch synthase and invertase. This also supplied the carbon necessary for the production of primary (amino acids, fatty acids and organic acids) and secondary (flavonoids and polyphenols) metabolites. There was consistently higher activity of antioxidant enzymes (catalase and peroxidase). Interestingly, species-specific reactions to MWCNT priming were observed, where L. sativum sprouts showed the highest antioxidant activity, followed by A. graveolens., Conclusion: MWCNT priming improves sprout growth and nutritional quality by boosting metabolic processes and antioxidant activity, presenting a promising approach for sustainable agriculture. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Harnessing solar energy for large-scale hydrogen fuel (H 2 ) production shows promise in addressing the energy crisis and ecological degradation. This study focuses on the development of GaN-based photoelectrodes for efficient photoelectrochemical (PEC) water splitting, enabling environmentally friendly H 2 production. Herein, a novel nanoflower Au/CuO/GaN hybrid structure was successfully synthesized using a combination of methods including successive ionic layer adsorption and reaction (SILAR), RF/DC sputtering, and metal-organic chemical vapour deposition (MOCVD) techniques. Structural, morphological, and optical characteristics and elemental composition of the prepared samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy, and energy-dispersive X-ray (EDX) spectroscopy, respectively. PEC and electrochemical impedance measurements were performed for all samples. The nanoflower Au/CuO/GaN hybrid structure exhibited the highest photocurrent density of ∼4 mA cm -2 at 1.5 V vs. RHE in a Na 2 SO 4 electrolyte with recorded moles of H 2 of about 3246 μmol h -1 cm -2 . By combining these three materials in a unique structure, we achieved improved performance in the conversion of solar energy into chemical energy. The nanoflower structure provides a large surface area and promotes light absorption while the Au, CuO, and GaN components contribute to efficient charge separation and transfer. This study presents a promising strategy for advancing sustainable H 2 production via efficient solar-driven water splitting., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The nonlinear optical properties of pure ZnO and Ni-doped ZnO thin films are explored using the Z-scan technique at different input laser intensities and an excitation wavelength of 750 nm by 100 fs laser pulses. The pure ZnO and Ni-doped ZnO thin films were prepared by radio frequency magnetron sputtering at room temperature. A scanning electron microscope equipped with energy-dispersive x-ray spectroscopy was used to measure the thickness and composition of the thin films, while a UV-visible spectrophotometer was used to measure the linear optical properties. The structure of the thin films was measured using x-ray diffraction. Saturable absorption (SA) was observed in the pure ZnO thin film, while Ni-doped ZnO illustrated a combination of SA and reverse SA (RSA). The nonlinear absorption coefficient ( β ) and nonlinear refractive index ( n 2 ) of both pure ZnO and Ni-doped ZnO thin films were found to be input laser intensity dependent. As the input laser intensity increased, the nonlinear absorption coefficient and the nonlinear refractive index of both samples increased. An enhancement of two times in the nonlinear refractive index was observed for the Ni-doped ZnO thin film compared to the pure ZnO thin film. The optical limiting behavior of pure ZnO and Ni-doped ZnO thin films was investigated, and the data demonstrated that Ni-doped ZnO thin film is a good candidate for optical limiter applications due to the presence of strong RSA.

The far ultraviolet C (UVC) light sources based on carbon nanotube (CNT) field emitters as excitation sources have become promising light sources for sterilization, disinfection, and water purification. However, the low light extraction efficiency of UVC-CNT light sources still hinders the practical application of these structures. Herein, we report an optimized aluminum (Al) reflector to enhance the light extraction efficiency of UVC-CNT light sources. Optical analysis of UVC-CNT light sources covered by the Al reflectors with various thicknesses ranging from 30 to 150 nm was performed to realize the optimized reflector. The UVC-CNT light sources exhibit the highest light extraction efficiency when the Al reflector layer has an optimized thickness of 100 nm. For comparison, the cathodoluminescence (CL) spectra were recorded for UVC-CNT light sources with and without the optimized Al reflector. The measured light output power and the estimated power efficiency of the UVC-CNT light-source-tube with Al reflector were enhanced by about 27 times over the reference. This enhancement is mainly attributed to the outstanding reflection effect of the Al reflector.

ZnS and their Cu-doped nanoclusters (NCs) were synthesized successfully using the wet chemical route with different Cu content. The crystalline structure was investigated using x-ray powder diffraction which assured the single-phase formation in cubic symmetry. High-resolution transmission electron microscope indicated the microstructure of NCs with a size ranging from 2-4 nm. A butterfly hysteresis (M-H) loop was observed at room temperature with large values of coercivity for the Cu content of x = 0.05. Photoluminescence emission spectra were recorded from 500-615 nm for pure and Cu-doped ZnS NCs at a 350 nm excitation wavelength. The sample exhibited green fluorescence bands peaking at 535, 544, 552.5, 558.2, and 560.6 nm, which confirmed the characteristic feature of Zn 2+ as luminescent centers in the lattice. The additional yellow and orange emissions are due to defect levels or/and impurity centers. The dielectric constant as well as the conductivity values increased with increasing Cu content.

The influence of temperature on the characteristics of a GaN-based 460-nm light-emitting diode (LED) prepared on sapphire substrate was simulated using the SiLENSe and SpeCLED software programs. High temperatures impose negative effects on the performance of GaN-based LEDs. As the temperature increases, electrons acquire higher thermal energies, and therefore LEDs may suffer more from high-current loss mechanisms, which in turn causes a reduction in the radiative recombination rate in the active region. The internal quantum efficiency was reduced by about 24% at a current density of 35 A/cm2, and the electroluminescence spectral peak wavelength was redshifted. The LED operated at 260 K and exhibited its highest light output power of ~317.5 mW at a maximum injection current of 350 mA, compared to 212.2 mW for an LED operated at 400 K. However, increasing temperature does not cause a droop in efficiency under high injection conditions. The peak efficiency at 1 mA of injection current decreases more rapidly by ~15% with increasing temperature from 260 to 400 K than the efficiency at high injection current of 350 mA by ~11%.

450 nm InGaN/GaN multi-quantum well (MQW) ligth-emitting diodes (LEDs) prepared on sapphire substrate with different thicknesses were fabricated and characterized. By thinning the sapphire substrate to 50 µm, it was found that the LED exhibited the highest light output power of ~48 mW under high injection current of 50 mA, improved by about 35% compared to that with 200 µm-thick sapphire without increasing the operating voltage. The electroluminescence intensity was increased and the spectral peak wavelength was blue-shifted, because the wafer bowing-induced mechanical stress alters the piezoelectric field in the InGaN/GaN MQW active region of the LED. The internal quantum efficiency was also improved by about 10% at an injection current of 50 mA. Moreover, the external quantum efficiency and light extraction efficiency were optimized because of enhanced light output intensity. The results confirmed that sapphire substrate thinning effectively alters the piezoelectric field in the InGaN/GaN active region, and hence increases both of the effective band gap and the probability of radiative recombination.

380 nm Ultraviolet (UV) light emitting diodes (LEDs) were grown on patterned n-type GaN substrate (PNS). Wet etched self-assembled indium tin oxide (ITO) nano clusters serves as dry etching mask for converting the SiO2 layer grown on n-GaN template into SiO2 nano dots by inductively coupled plasma etching. In the pre-experiment, crystal quality and optical properties of n-GaN were greatly improved by applying PNS process. In this work, etch-pits density (EPD) method confirmed that PNS with SiO2 nano dots have superior crystalline properties. Thus Reference LED without PNS, 1-step PNS LEDs with SiO2 nano dots size were 200 nm, 250 nm, 300 nm and 300 nm 2-step PNS LED were fabricated. LEDs show almost the same operating voltage of about 3.4 V at an injection current of 50 mA. Light intensity was enhanced by ~2.1 times and 3.2 times for 300 nm 1-step and 300 nm 2-step PNS, respectively. FDTD simulation results show a similar tendency. As a result, PNS promotes epitaxial lateral overgrowth (ELOG) for defect reduction as well as act as a light scattering point.

n-type GaN epitaxial layers were regrown on the patterned n-type GaN substrate (PNS) with different size of silicon dioxide (SiO2) nano dots to improve the crystal quality and optical properties. PNS with SiO2 nano dots promotes epitaxial lateral overgrowth (ELOG) for defect reduction and also acts as a light scattering point. Transmission electron microscopy (TEM) analysis suggested that PNS with SiO2 nano dots have superior crystalline properties. Hall measurements indicated that incrementing values in electron mobility were clear indication of reduction in threading dislocation and it was confirmed by TEM analysis. Photoluminescence (PL) intensity was enhanced by 2.0 times and 3.1 times for 1-step and 2-step PNS, respectively.