Influence of the Transparent Conductive Oxide Type on the Performance of Inverted Perovskite Solar Cells

In inverted perovskite solar cells (PSCs), indium tin oxide (ITO) is the most commonly used transparent conductive oxide (TCO) layer for coating glass substrates. However, the preference for the ITO has never been clearly stated. Although the ITO layers are generally more conductive than the fluorine-doped tin oxide (FTO) layers, indium is a rare and expensive metal. In this work, the possibility of using FTO instead of ITO is explored. The electrical performance and surface morphology of the two TCO substrates are investigated, as well as the performance of PSCs fabricated with them. Although there is a large difference between the surface roughness of the two TCO substrates, this morphological feature was found to have no effect on the performance of the corresponding cells. The champion device was fabricated with an FTO-coated glass substrate, and the improved efficiency was attributed to the higher short-circuit current density. The results obtained during the development of this work indicate that FTO can indeed be used as a TCO substrate for inverted perovskite solar cells without sacrificing efficiency and stability, with the important feature of being cheaper and more environmentally friendly than ITO.