Reassessing the role of ITO thickness to optimise the device performance in perovskite solar cells

Perovskite solar cells (PvSCs) are promising next-generation photovoltaic devices due to their high efficiency and low fabrication cost. Indium tin oxide (ITO), used as a transparent electrode in solar cells, significantly impacts device performance, however, its thickness is unaccounted for due to standardised commercial availability. This study systematically investigates the role of ITO thickness in planarn-i-pperovskite solar cells using a combined opto-electrical simulation. Different ITO thicknesses (70, 100, 150, and 190 nm) were analysed to understand and explore thickness dependent optical interference and dissipative absorptions, and their resultant effect on carrier generation, charge transport, and overall device performance. Optical simulations using the transfer-matrix method show that constructive interference builds up at intermediate ITO thicknesses (100-150 nm), which in turn enhances the visible-light transmission and increases light absorption within the perovskite layer. Electrical simulations confirm the results of optical simulations, which yield higher short-circuit current density, improved fill factor, and reduced resistive losses. Devices with 150 nm ITO exhibit the highest short circuit current density of 21.42 mA cm^-2and power conversion efficiency (PCE) of 22.67%, while those with 70 and 100 nm show short-circuit current density of 21.21 mA cm^-2and 21.25 mA cm^-2withPCEof 22.90% and 23.23% respectively, presenting a promising cost-efficient guidance to researchers without much compromise in the performance. This study exemplifies that ITO thickness is a critical, still underexplored design parameter, and its optimisation provides a guiding route for achieving high efficiency of photovoltaic devices, while reducing material costs for next-generation photovoltaics.