•In this paper, we designed, simulated and analyzed high efficiency of SnS-based solar cells.•Photovoltaic performance of tilted nanocolumns SnS-based solar cells was studied.•The best efficiency was ...found for the sample prepared at highest deposition angle.
In this paper, we designed, simulated and analyzed high efficiency of SnS-based solar cells. This work is related to the influence of a glancing angle deposition (GLAD) technique for deposition of SnS layer, on the photovoltaic performance of SnS-based solar cells. The photovoltaic parameters have been calculated for the samples prepared at different oblique incident flux angles (α = 0°, 45°, 55°, 65°, 75°, and 85°). The best efficiency was found for the sample prepared at α = 85°. We simulated the J-V characteristics and showed how the absorber layer that prepared by GLAD technique at different incident flux angles, influence the short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and efficiency (η) of solar cell.
In this study, we provide a systematic study on the origin of green and blue emission from luminescent silicon nanoparticles (Si-NPs) synthesized in water using a nanosecond pulsed laser ablation ...methodology. Here we report a direct one-step process to make ultra-small Si-NPs (∼3 nm mean size) by utilizing spiral beam scanning. In each ablation cycle, this scanning scheme collects generated nanoparticles towards the center and ablates them in subsequent cycles. Therefore, the resultant Si-NPs can reach very small sizes in a short time with high uniformity in their size distribution. Further, we investigate the effect of laser fluence on the emission properties of the obtained nanoparticles. For this aim, two different values of 60 mJ cm
−2
and 30 mJ cm
−2
laser fluences are employed to achieve green and blue emitting Si-NPs, respectively. Our results show that the emission spectrum for both blue and green Si-NPs has two main peaks at 426 nm and 520 nm, but their relative intensity ratios are different for these two cases. The findings of this study suggest that the blue emission originates from oxide related surface defects at the Si/SiO
x
interface, while the green emission stems from grain boundaries existing at the NP surface. We found that these two types of disorders can be controlled by tuning the laser power.
In this study, we provide a systematic study on the origin of green and blue emission from luminescent silicon nanoparticles (Si-NPs) synthesized in water using a nanosecond pulsed laser ablation methodology.
In this paper, we demonstrate the enhancement of photovoltaic (PV) solar cell efficiency using luminescent silicon nanoparticles (Si-NPs). Sub-10 nm Si-NPs are synthesized via pulsed laser ablation ...technique. These ultra-small Si nanoparticles exhibit photoluminescence (PL) character tics at 425 and 517 nm upon excitation by ultra-violet (UV) light. Therefore, they can act as secondary light sources that convert high energetic photons to ones at visible range. This down-shifting property can be a promising approach to enhance PV performance of the solar cell, regardless of its type. As proof-of-concept, polycrystalline commercial solar cells with an efficiency of ca 10% are coated with these luminescent Si-NPs. The nanoparticle-decorated solar cells exhibit up to 1.64% increase in the external quantum efficiency with respect to the uncoated reference cells. According to spectral photo-responsivity characterizations, the efficiency enhancement is stronger in wavelengths below 550 nm. As expected, this is attributed to down-shifting via Si-NPs, which is verified by their PL characteristics. The results presented here can serve as a beacon for future performance enhanced devices in a wide range of applications based on Si-NPs including PVs and LED applications.
Nowadays, the increase in population growth rate and followed by anthropogenic activities such as urbanization, industrialization, mining and agriculture practices continuously increase the amount of ...heavy metals in the environment especially groundwater resources. Therefore, qualitative assessment of groundwater resources is of great importance for maintaining public health and for this reason, this study was conducted to qualitative assessment of groundwater resources of Asadabad Plain using WQI, Cd, HPI, HEI, PoS and MI indices in 2018. Materials & Methods: In this descriptive cross-sectional study, 120 groundwater samples were collected from 20 stations in the spring and the summer seasons and their temperature, pH and EC values were measured on-site. In the laboratory, the values of physicochemical parameters were determined according to the standard methods. Also, the content of heavy metals was determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). All statistical analyses were performed using SPSS software. Results: The results showed that the average concentrations of Na, PO4-, Cl-, Ca, Mg and NO3- (mg/L) in samples of the spring season were 21.8, 0.230, 0.170, 69.0, 21.1 and 19.3, respectively; and in the summer season were 8.14, 0.190, 0.160, 75.3, 15.6 and 19.8, respectively. Also, the average concentrations of As, Fe, Zn, Pb, Cd, Cr, Cu, Mn and Ni (μg/L) in samples of the spring season were 5.10, 1.61, 0.970, 7.82, 0.230, 1.25, 3.58, 0.360, and 1.30; and in the summer season were 21.4, 1.62, 1.24, 7.63, 0.200, 1.00, 6.73, 0.430, and 1.01, respectively, and except for As in samples of the summer season, the average concentrations of all elements in groundwater samples of both seasons were lower than the maximum permissible concentration (MPC) established by WHO for drinking water. In addition, water quality index (WQI), pollution index (Cd), heavy metal pollution index (HPI), heavy metal evaluation index (HEI), quality index (PoS) and heavy metal index (MI) of samples of the spring season with values of 18.2, -7.53, 9.86, 1.64, 298 and 1.64, respectively, indicate the quality of groundwater were categorized in "excellent and very good", "low pollution", "low pollution", "low pollution", "low pollution" and " slightly affected" classes and in the summer season with values of 17.9, -5.94, 9.86, 3.05, 602, 3.05, respectively, were categorized in "excellent and very good", "low pollution", "low pollution", "low pollution", "high pollution" and "moderately affected" classes. Conclusion: Although only the average values of As in groundwater samples of the summer season were higher than the MPC, management of the use of agricultural inputs such as pesticides, chemical and organic fertilizers and municipal wastewater for irrigation to maintain the quality of groundwater resources of the study area is recommended.
In this letter, a novel planar monopole antenna with a variable frequency band-notch characteristic for ultrawideband (UWB) applications is presented. The UWB property is achieved by embedding two ...shorted rectangular quarter-wavelength resonators. Two other L-shaped quarter-wavelength resonators coupled to the radiating patch are also used in order to generate the frequency band-stop performance and control antenna characteristics such as band-notch frequency and its bandwidth. The designed antenna has a stopband of 5-5.9 GHz while maintaining wideband performance from 3.1 to 11 GHz with VSWR <; 2.
The underlying cause of asymmetric diffusion solidification which alters microstructure during transient liquid phase bonding under low temperature gradient was studied. A new solute-conserving ...asymmetric numerical model coupled with experimental verification showed that a transition from bi-directional to unidirectional solidification, under a constant temperature gradient, is controlled by competition between liquid and solid-state diffusion at one of the two liquid–solid interfaces. This mechanistic understanding would aid a more effective use of the process.
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