Characterization of SnxSey / Sno2-ni prepared by spray pyrolysis for photovoltaic application

Abstract

Nickel doped tin oxide and tin monoselenide thin films were coated using spray pyrolysis. Nickel doped tin oxide Precursor solution was prepared using a 0.05M Tin (II) Chloride (SnCl4.2H2O) and 0.05M Nickel chloride 6-hydrate (NiCl2.6H2O) in de-ionized water and then being added in ethanol in the ratio 1:1 to get equal proportions, followed by about 2-3 drops of hydrochloric acid. Doping tin oxide was done using uniform concentration of (NiCl2.6H2O) of 0-10 %. Precursor solution of tin selenide SxSey was prepared using alcoholic solution consisting of tin chloride Sncl2.2H2O and 1,1-dimethl-2-selenourea (C3H8N2Se) and then heated while stirring and left for about a week. Samples of (SnxSey) were made in ratios of 1:0.4 to 1:1.4. Thin films of SnO2, SnO2: Ni, SnxSey and SnxSey- SnO2: Ni were deposited on glass substrate using Spray pyrolysis at deposition temperature of 375oC. The samples of tin selenide were characterized by measuring their optical properties using UV-VIS-NIR spectrophotometer 3700 DUV in the range 280nm to 1200nm and were used to calculate solid state and optical properties namely band gap (Eg), refractive index (n) and absorbance (α). The optical band gap of deposited tin selenide ranged between 1.39-2.23ev. The sample of Sn:Se1.0 had the highest absorbance of over 46.26% and lowest transmittance of about 44.3% in the VIS-NIR region. The optical band gap of deposited Nickel doped tin oxide ranged between 3.65-3.75ev. The sample of Nickel doped tin oxide of 2% concentration had the highest transmittance of 86.2% and lowest absorbance of about 5.05% in the VIS-NIR region. These properties are suitable for window and absorber layers for application in photovoltaic cell. The diode characteristics such as short circuit current (Isc) = 1.118mA, open circuit voltage (Voc) = 0.607V, fill factor (FF) = 0.6792 and conversion coefficient (η) = 0.4609 % was obtained for Tin selenide (SnxSey) and nickel doped tin oxide (SnO2: Ni) solar cell.