Efficient Cu(In,Ga)Se2 based solar cells prepared by electrodeposition

CuInSe2 and Cu(In,Ga)Se-2 precursor layers have been prepared by electrodeposition, with morphologies suitable for device completion. These precursor films were transformed into photovoltaic quality films after thermal annealing without any post-additional vacuum deposition process. Depending on the preparation parameters annealed films with different band gaps between 1 eV and 1.5 eV have been prepared. The dependence of resulting solar cell parameters has been investigated. The best efficiency achieved is about 10,2% for a band gap of 1.45 eV. This device presents an open circuit voltage value of 740 mV, in agreement with the higher band gap value. Device characterisations (current-voltage, capacitance-voltage and spectral response analysis) have been performed. Admittance spectroscopy at room temperature indicates the presence of two acceptor traps at 0.3 and 0.43 eV from the valance band with density of the order of 2.10(17) cm(-3) eV.