Electrical performance of organic/inorganic hybrid solar cell devices based on n-type GaAs substrate orientations and a conjugated polymer (PANI)

摘要

This article presents the electrical performance of hybrid organic/inorganic solar cell devices. Hybrid polyaniline (PANI)/n-GaAs photovoltaic devices were fabricated by spin coating of PANI thin films on conventional (100) and high index (311) A and (311)B n-GaAs substrates. The solar cell parameters of these devices, as obtained by current density-voltage (J-V) under illumination conditions, were found to be dependent on the substrate orientation. The PANI/(311)A n-GaAs devices revealed the best performance, with an open-circuit voltage (V_(oc)) of 207 mV, a short-circuit current density (J_(sc)) of 0.267 mA/ cm~2, a fill factor (FF) of 25% and an efficiency (η) of 1.4 x 10~(-2)% which is higher than that of PANI/(100) and (311 )B hybrid samples. Additionally, the electrical properties of these junction diodes have been studied utilizing dark current density-voltage (J-V), capacitance-voltage (C-V), deep level transient spectroscopy (DLTS) and Laplace DLTS techniques. The dark J-V measurements showed that the rectification ratio (I_F/I_R), turn-on voltage (V_(on)) and barrier height (Φ_b) of PANI/(311) A n-GaAs heterostructure are higher than those of PANI thin films deposited on (100) and (311 )B n-GaAs substrates. The DLTS and Laplace DLTS measurements illustrated that the number of traps in PANI/(311 )A n-GaAs devices is lower than that in PANI/(100) n-GaAs and PANI/(311)B n-GaAs devices, corroborating with J-V results.