The Effect of Defects on the Overall Performance of CuInSe2/Cds/ZnO Thin Film Solar Cells

Ternary CuInSe2 (CIS) polycrystalline thin films were successfully deposited on fluorine-doped tin oxide (FTO) substrate by using electrochemical deposition techniques. The influence of film deposition parameters such as bath composition, pH and deposition time on film properties were studied. The structural, morphological, composition and optical properties of the electrodeposited films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectroscopy, respectively. The current voltage (I-V) characteristics of CIS/CdS/ZnO solar cells were also obtained. Measured photoconversion efficiencies (PEC) were in the range of 2-2.5% with open circuit voltage (Voc) about 34.65mV, short circuit current (Jsc) 1.68 mA/cm(2) and fill factor (FF) 38.18% under 100 mW/cm(2) tungsten halogen illumination for an active area 1.2 cm(2) devices. The CuInSe2 overall performance of thin film solar cells were also studied by one dimension simulation software SCAPS. The main photovoltaic parameters were obtained as a function of the defects density (Nt) that was changed from 9.0.10(12) to 9.0.10(16) cm(-3). For the lowest defect concentration used the PCE is abouyt 21.43 % and Voc 61.09 mV, while when the density increased to 9.0.10(16) cm(-3) both efficiency and Voc decrease dramatically to 2.39% and 20.43 mV, respectively.