Effects of substrate type and orientation on the photovoltaic and diode performance of PANI-Based organic/inorganic hybrid devices

This article reports the influence of substrate type and orientation on the photovoltaic and electrical performance of organic/inorganic hybrid devices. Polyaniline (PANI) was spin-coated at 2000 rpm onto (111)B n-type GaAs, (100) n-Si, and (111) n-Si substrates to create hybrid solar cell devices. The current–voltage (I-V) characteristics under illuminated (60 mW/cm2) and dark conditions at room temperature were carried out to determine solar cell and diode parameters. In the presence of illumination, the current density–voltage (J-V) characteristics exhibited that the PANI/(111)B n-GaAs heterostructure was superior to the PANI/Si devices in terms of photovoltaic performance. The PANI/(111)B n-GaAs hybrid device has an open-circuit voltage (Voc) of 129 mV, a short-circuit current density (Jsc) of 10.8 mA/cm2, and the highest conversion efficiency ( $$\eta$$ ) of 0.83 × 10–3%. On the other hand, dark current–voltage (I-V) measurements revealed that the PANI/(111) n-Si device has better diode parameters, such as a rectification ratio (RF) of 50.20, a high barrier height ( $${\upphi }_{\text{b}}$$ ) of 0.69 eV, and the lowest ideality factor (n) of 3.07. Interestingly, the results show that the GaAs-based device is better at solar cell performance, while the Si-based device, especially on the (111) plane, presents better electrical performance as a diode junction. This clearly confirms that the operational mechanisms of PANI-based hybrid solar cells are significantly affected by the semiconductor material substrate and crystallographic orientation-selection.