Counter Electrodes Based on Polyaniline/carbon Nanotube/CuxS Nanocomposites for CdS Quantum Dots‐Sensitized Solar Cells

Quantum dot‐sensitized solar cells (QDSSCs) are promising for sustainable energy generation but face efficiency and cost barriers. In this configuration, counter electrodes (CEs) play a crucial role in overcoming these barriers. In this study, the novel CEs are investigated based on nanocomposites of polyaniline (PANI/Cu x S) and polyaniline‐multi‐walled carbon nanotubes/copper sulfide (PANI‐MWCNT/Cu x S) electrodeposited on a fluorine‐doped tin oxide (FTO) substrate to overcome these challenges. The CEs are characterized by Infrared and Raman spectroscopy, X‐ray diffraction, scanning electron microscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy. These nanocomposites based on polyaniline (PANI) are applied as CE in cadmium sulfide (CdS) QDSSCs, which presented energy conversion efficiencies of 1.99% and 2.39%, respectively, under standard irradiation, representing an increase of more than 50% compared to the Cu x S CE. These PANI‐based CEs presented lower charge‐transfer resistance (32 Ω) and better photovoltaic performance than conventionally used Cu and Cu x S CEs, and they are promising for application in QDSSCs because they have been prepared with materials that are widely used in electronic devices and can be an option for large‐scale production.