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In this work, high quality titanium dioxide thin films were grown by an efficient, less expensive and rapid method of Atmospheric Pressure Chemical Vapor Deposition (APCVD) from TiCl4 precursor for application as antireflection coatings on monocrystalline silicon solar cells with the aim to reduce the front surface reflection losses. The microstructural, electrical and optical properties of the produced coatings were successfully characterized by Atomic Force Microscopy (AFM), Four Point Probe (FPP) and Spectroscopic Ellipsometry (SE). The produced coatings were uniform, homogenous and relatively smooth. The density of the deposited TiO2 films is found to be ρ ′ = 3.11 g/cm3. The porosity of these films is estimated to ϕ = 24%. A perfect agreement between the AFM results and the ellipsometric results was confirmed. The refractive index of our TiO2 thin films was found to be n = 2.25 at the wavelength λ = 550 nm, with a thickness of 56.2 nm. Our results show the possibility to fabricate TiO2 layers with the optimal optical qualities required for antireflection coating, using the APCVD technique. An excellent agreement is reached between our experimental results and calculated results for TiO2 single‐layer antireflection coating on monocrystalline silicon solar cells. The electrical resistivity of the deposited TiO2 films at 450°C annealed at 450°C for 1 hr, was found to be ρ = 1.7 × 10‐3 Ω.cm. The sheet resistance of our TiO2 films was equal to R□ = 303 Ω/□. The obtained results demonstrate the real opportunity of the APCVD technique to prepare high quality antireflection coatings for high efficiency silicon solar cells. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

In order to improve the photovoltaic (PV) production, the researchers are interested in developing new methods to reach the Maximum Power Point (MPP) produced by the photovoltaic field to be injected into the utility grid. This article describes a new method called the Optimized Steepest Gradient Method (OSGM), it is based on the first (gradient) and second order (hessian) derivatives of the power function in order to find the best variation of the voltage (Vpv) with the calculation of the optimal step allowing the convergence to the tension value (Vref) which ensures the MPP. The mathematical model has been developed and implemented under Matlab/Simulink environment. To analyze Maximum Power Point Tracking (MPPT) algorithm performances, time response, oscillation, overshoot and stability are taken into account. The OSGM is implemented and compared to three others algorithms (one of these algorithm is the ANFIS proposed in previous work). Performances obtained by the proposed algorithm offer faster response, less oscillations around MPP and a low energy loss. In addition, numerical computation of the gradient and the hessian of the power function allow bypassing modeling inaccuracies.