Philippe Thevenin

Optimization of parameters for deposition of ZnO films by sol gel using Taguchi method

Transparent conductive SnO2 films were deposited on glass substrates by sol-gel spin coating method. Taguchi method was used to find the optimal deposition parameters, three influential parameters were selected in this experiment, Concentration of Tin (II) ions, annealing temperature and pre-annealing temperature. By employing the analysis of variance, we found that the annealing temperature and the precursor are the most influencing parameters on the properties of SnO2 films. Under the optimized deposition conditions, the SnO2 films showed high crystal quality, and high transmittance of 80% in the visible region.

Optimization of the output parameters in kesterite-based solar cells by AMPS-1D

The presence of defects, grain boundaries and other impurities in Cu2ZnSnS4 (CZTS) thin film material is detrimental on output performances of fabricated solar cells. Moreover the formation of non stable and high resistance contacts to CZTS contribute also to lower the values of short circuit density (Jsc), open circuit voltage (Foc), fill factor (FF) and therefore the efficiency of thin film solar cells. This study evaluates the baseline ZnO/CdS/CZTS cell structure using AMPS-1D program and quantifies reasons for the efficiency limits predicted in such a device. The effect of back contact material, acceptor concentration as well as the absorber thickness on CZTS cell performance is also studied. The solar cell with a back contact work function of 5.6 eV, an acceptor concentration of 4×1015cm-3 and an absorber layers thickness of 2250 nm showed the best performance with a conversion efficiency of 15.68%. This presented work is essential because it can contribute to fully understand the performance of CZTS solar cell and to fabricate cells with a precise control of the process parameters with a reduced surface as well as bulk recombination and secondary phases.

Influence of silver doped indium sulfide on the structural and optical properties of spray pyrolyzed indium sulfide thin films

Silver doped indium sulfide thin films were deposited on ordinary glass substrates at 350°C, using chemical spray pyrolysis (CSP) technique. The samples have been prepared by varying the Ag/In ratio in solution from 0 % to 4 %. The effect of silver on structural and optical properties of In2S3:Ag thin films has been investigated in detail using various characterization tools. XRD patterns confirmed that all the films have a nanocrystalline nature. The Raman spectroscopy showed the main mode at 306 cm−1 and 327 cm−1 indicating the presence of the β-phase in all films. Optical transmittance of spray pyrolyzed films exceeds 80% in the visible region and band gaps are estimated varying from 2.60 eV to 2.73 eV.

Performance Analysis and Comparison of Different Photovoltaic Modules Technologies under Different Climatic Conditions in Casablanca

The main goal of this work is to study the performance of silicon-based photovoltaic modules of different technologies (Monocrystalline (c-si), Polycrystalline (p-si) and Amorphous (a-si)) installed on rooftop of the Ben m’sik faculty at Hassan II university, Casablanca, Morocco (Latitude 33°36”N, Longitude 7°36”W). This study is based on daily measurements under various climatic conditions (clear, cloudy and rainy). In order to improve the performance evaluation, the real-time measurements were taken for every five minutes of different climatic parameters (solar irradiation, ambient temperature, module temperature, wind speed and direction) and electrical parameters (power, current and voltage). In fact, we studied the PV array efficiency, the inverter efficiency and the system efficiency. In addition, we performed an evaluation to the PV array, reference and final yields and the performance ratio (PR). The results show maximum values for module efficiency, final efficiency and system efficiency on a clear day for all three technologies due to high irradiation. The maximum values of PR are 72.10%, 91.53% and 86.20%, are obtained on a cloudy day, this is due to the low temperature and the high wind speed. Minimum values of PR, module efficiency, reference efficiency and final efficiency on a rainy day are due to the low sun exposure and the rain which affect the generated energy and stability of PV systems.

NUMERICAL SIMULATION OF SOLAR CELLS BESED CZTS BUFFER LAYER (ZnO1-XSX) USING SCAPS-1D SOFTWARE

Although the CdS buffer layer has several advantages such as its wide bandgap, its relatively high carrier density, etc..., one of the major drawbacks of this latter is the presence of cadmium, a toxic element, even in small amounts. Research work, currently, are shifted on the possibility of replacing CdS by a buffer layer devoid of cadmium. Among non-toxic buffer layers studied in the literature, we cite In2S3, ZnS, ZnSe and SnS2. This manuscript presents the numerical study, using the SCAPS-1D program, the effects of the sulfur content in the buffer layer Zn (O,S) on the electrical parameters of the solar cell ZnO: Al / i-ZnO / Zn (O, S) / CZTS /. Material parameters used in this simulation were selected on the basis of literature values. Changes in the band gap and electron affinity of Zn (O, S) were calculated from the law of Vegard. The numerical results found, for a thickness of the absorbent layer CZTS equal to 2.5µm, show that from the sulfur content equals to 45% the efficiency varies only slightly, and is about 19%. The maximum relative error, over the efficiency of the same cell with CdS buffer layer does not exceed 1.5%, value that can be reduced by increasing the thickness of the absorbent layer CZTS.

Growth and characterization of CuO thin films prepared by spray pyrolysis with various precursors

in In this work, we study the effect or the different copper precursors on the structural optical and electrical properties of CuO thin films deposited on glass substrates using spray pyrolysis technique, the phase of tenorite (CuO) are identified using X-Ray diffraction. A single phase without impurities is observed for the three precursors. The band gap energy and others optical parameters are calculated using absorbance/transmittance data giving by spectrophotometry. The semiconductor aspect of our films are showed by four probes method.

Synthesis and characterisation of Cu 2 ZnSnS 4 thin films prepared by sol gel method for photovoltaic applications

This study reports the elaboration and characterisation of Cu2ZnSnS4 (CZTS) thin films prepared by low cost sol gel method associated to spin coating technique. The CZTS thin films were prepared on ordinary glass substrates and annealed at 350°C during 4 min, 8 min, 12 min and 16 min of the samples Z1, Z2, Z3 and Z4 respectively, in order to study the effect of annealing times on the structural, optical and electrical properties. The samples were characterized using X-ray diffractometer, Spectrophotometer UV-VIS and 4-points probe system. The optical parameters were measured and calculated from the transmittance and absorbance spectra in the wavelength between 350 and 1000 nm. The sheet resistance and the resistivity were determined by 4-points probe method. The CZTS films showed a kesterite structure of (112), (200), (220) and (312) plans, the preferential orientation along the (112) plan. The band gap energy of sample Z1 is 1.5 eV, the sheet resistance and resistivity of sample Z1 are 3.61 kΩ/square and 0.257 Ω.cm respectively.

Synthesis of doped and undoped TiO 2 thin films prepared by sol gel

The influence of doping level at 0%, 3%, 5% and 7% by tin dioxide on the optical and electrical properties of TiO2 thin film were deposited on glass substrates by sol gel technique dip coating method.

Effect of F-doping on structural, electrical, and optical properties of ZnO thin films for optoelectronic application

In this work, Fluorine doped Zinc oxide (FZO) thin films were deposited by the sol-gel spin coating method. Zinc acetate dihydrate, ethanol and mono-ethanolamine were used as precursor, solvent and stabilizer, respectively. The atomic percentages of dopant in solution were [F/Zn]=1%,2%, 4% and 6%. The effect of F doping on the structural, optical and electrical properties of ZnO films were investigated by X-ray diffraction (XRD), Four-Point probe technique and UV-visible spectrophotometery. The results from the X-ray diffraction show that the pure ZnO thin films have polycrystalline structure, hexagonal wurtzite type. All the films have a highly preferential c-axis orientation, and exhibited (002) plane as a preferential growth in all the dopant ratios. Grain sizes of the films were varied in range of 36.5 to 46.2 nm. The optical transmission is decreased with the increase of the dopant concentration. The band gap energy values were determined as 3.252 eV, 3.267 eV, 3.295 eV, 2.299 eV and 3.315 eV, respectively for undoped ZnO, 1, 2, 4 and 6% mole FZO thin films. A minimum resistivity of FZO (2.72 *10−3) was obtained for the film doped with 29% mol of F. These results make FZO thin films an attractive candidate for transparent and electric material applications.

Structural and optical properties of CuIn 1−x Ga x S 2 absorber layer for solar cells synthesized by spray pyrolysis

In this study, we investigated the effect of the chemical ratios (x=Ga/In+Ga) on the structural and optical properties of the chalcopyrite Cu(In<inf>x−1</inf>, Ga<inf>x</inf>)S<inf>2</inf> thin films made by spray pyrolysis. Structural analysis by X-ray diffraction revealed that the CIGS crystallizes in a polycrystalline structure with chalcopyrite phase and a preferential growth orientation [112]. The best crystallinity was observed for the film prepared with the chemical ratio x = 0.9. The grain size of the films of CIGS decreases with chemical ratio (Ga+In)/Ga increases. The Optical properties was calculate from the measured spectral transmittance T<inf>λ</inf> and reflectance R<inf>λ</inf> allow us to determine the direct band gap energy value which increases by increasing the x ratios and it is in the range 1.64–1.70 eV, indicating that Cu(In<inf>1−x</inf>Ga<inf>x</inf>)S<inf>2</inf> compound has an absorbing property favorable for photovoltaic applications.