Insufficiencies of the Single Exponential Model and Efficiency of the Double Exponential Model in the Optimization of Solar Cells Efficiency

Single and double exponential models are confronted to determine the most adapted model for optimization of solar cells efficiency. It is shown that the single exponential model (SEM) presents some insufficiencies for efficiency optimization. The interest of the double exponential model to optimize the efficiency and to achieve an adequate simulation of the operation of solar cells is demonstrated by means of I-V characteristics plotting

New Coefficients of the Minority Carrier Lifetime and Bandgap Narrowing Models in the Transparent Emitter of Thin Film Silicon Solar Cells

In this study we have determined new coefficients for the physical model describing the band-gap narrowing and the minority carriers lifetime. This was accomplished according to the doping level of the thin emitter. This model allows us to take into account both the effects of the heavy doping and the majority carrier degeneration for the very high level of doping. The results we obtain by the corrected model are in good agreement with those reported in the literature and in different experiments. They show us the possibility of accurately evaluating the performances for the n+p silicon solar cell. This model is then used to introduce a new concept for the thin layer emitter, called transparent emitter

Lavender oil as an ecofrindly inhibitor for mild steel in 1 M HCl

Lavender oil is extracted from lavender herb, collected in the east region of Morocco (Tafoughalt) and tested as corrosion inhibitor for mild steel in 1 M HCl. The inhibiting effect was studied by weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Polarisation measurements show that lavender oil essentially acts as a cathodic inhibitor. The natural oil reduced the overall corrosion current density. The protection efficiency was found to increase with oil content to obtain ca. 90% at only 2 g L-1 and kept its inhibiting efficiency the same even at higher temperatures. The adsorption of lavender oil on mild steel followed the Langmuir's isotherm model. The thermodynamic parameters for inhibiting process were calculated and interpretation of the results was given

Synergistic Combination Effect of Salvia officinalis and Lavandula officinalis on the Corrosion Inhibition of Low-Carbon Steel in the Presence of SO42−- and Cl−-Containing Aqueous Environment

The corrosion inhibition of low-carbon steel in 1 M H2SO4 and HCl solutions by the admixture of Salvia officinalis and Lavandula officinalis essential oil extracts was studied through potentiodynamic polarization analysis, coupon measurement and optical microscopy. The carbon steel undergoes severe surface deterioration in H2SO4, while the morphology of the steel from HCl showed selective deterioration with numerous corrosion pits in the absence of the oil extracts. The extracts performed effectively in the acid media with optimal inhibition efficiency of 86.92 and 96.90% in H2SO4, and 84.68 and 97.59% in HCl from potentiodynamic polarization and coupon analysis. The oil extract displayed anodic inhibition properties in H2SO4 due to surface coverage of the steel and cathodic inhibition in HCl due to selective precipitation of extract molecules. Thermodynamic calculations show the extracts adsorbed onto the steel surface, effectively suppressing the corrosion reactions through chemisorption mechanism according to the Langmuir, Frumkin and Freundlich adsorption isotherms