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In this work, polyaniline (PANI) base-single wall carbon nanotubes (SWCNTs) composite counter electrode (CE) and N3 ruthenium dye sensitized TiO2, prepared using hydrothermal method, photoelectrode were assembled to form a dye sensitized solar cell (DSSC). Three different compositions (ITO/PANI, ITO/PANI-SWCNTs and ITO/PANI-SWCNTs-graphite) of counter electrodes were fabricated and used for constructing different DSSCs. The morphologies of PANI-SWCNTs counter electrode and TiO2 mesoporous film surfaces were investigated using scanning electron microscope (SEM). The electrical properties of the resultant solar cells were investigated by measuring the current density–voltage (J-V) under illumination condition and impedance measurements. The photovoltaic cell characteristics, i.e., open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and energy conversion efficiency (η) were evaluated under illumination and were found to be 530 mV, 12 mA/cm2, 0.3 and 1.8%, respectively for ITO/PANI-SWCNTs/graphite/electrolyte/ TiO2-N3 dye/ITO heterostructure. The depositing of a graphite layer on the PANI/SWCNTs nanocomposite creates a novel structure for the counter electrode and enhances the photovoltaic cell efficiency by 80%.

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Organic–inorganic perovskite solar cells (PSCs) have been emerging as one of the most promising photovoltaic technologies. Surface morphology is considered as a key-parameter in energy alignment and plays a dominant role in specifying the device performance. The large grains and low roughness enhance the transport of charge carriers from perovskite layers to the transport layers, and this reflects on the delivered power conversion efficiency (PCE). Therefore, in this study, we investigated the influence of the fabrication parameters on the grain size and the morphology of perovskite layers, thereby the PCE of PSCs. These parameters included the anti-solvent nature (chlorobenzene or toluene), annealing temperature, and annealing ramp rate (slow or flash annealing). The scanning electron microscope confirmed that flash annealing results in a better morphology than slow annealing whether by employing an anti-solvent dripping or not. Furthermore, the dripping of chlorobenzene as an anti-solvent produced better morphology and large grains compared with toluene. Therefore, combining chlorobenzene with flash annealing induced the formation of large grains, full cover, and a uniform perovskite layer, which reflects on the performance of the fabricated PSCs. Finally, employing the aforementioned optimum preparation parameters to fabricate carbon-based PSCs resulted in decent PCE, current density short circuit (Jsc), open circuit voltage (Voc), and fill factor (FF) of 7%, 11.3 mA/cm2, 0.74 V, and 34%, respectively.

In this work, a novel dye sensitized solar cell (DSSC) structure -ITO/(TiO2/WO3)/N3dye/electrolyte/graphite/PANI/SWCNTs/ITO- was fabricated with different ratios of WO3 nanoparticles. It was observed that the depositing of a layer of WO3 nanoparticles- 3% wt. ratio- on TiO2 photoelectrode, enhances the DSSC efficiency from 0.28 % to 1.2%. This is due to reduction in charge injection resistance at the electrolyte/photoelectrode interface.