Electrodeposited (Cu-In-Se)/polypyrrole PV structures

Hybrid PV structures based on polycrystalline photoabsorber Cu-In-Se (CISe) and electrically conductive polymer polypyrrole (PPy) were prepared using the electrodeposition technique. The PPy is considered as p-type barrier layer on n-CISe in the cell structure. Photoactive CISe thin films of various compositions were deposited electrochemically onto glass/ITO substrates from aqueous solutions containing CuSO4, In2(SO4)3 and SeO2. All the obtained polycrystalline CISe films were annealed in vacuum to improve the crystalline structure and etched in 10% KCN to remove the additional phases. In order to prepare the PV structures, thin PPy films doped with β-naphthalene sodium sulfonate were galvanostatically electrodeposited onto the CISe films. Appropriate parameters of electrodeposition were selected experimentally. The morphology and thickness of the prepared film layers were determined using the SEM technique. The chemical composition of the CISe films was determined by energy dispersive X-ray spectroscopy (EDS). To investigate the electrical properties of the obtained structures, current-voltage and impedance characteristics were measured. The best structure showed an open-circuit voltage of 138 mV and a short-circuit current density of 2.55 mA/cm2 under white light illumination with an intensity of 100 mW/cm2.