Researchers from the Indian Institute of Technology Bombay have demonstrated a room-temperature, non-destructive method for depositing amorphous indium zinc oxide (a-IZO) transparent electrodes in perovskite solar cells, providing a step forward in device durability and performance compared to conventional indium tin oxide (ITO) electrodes.
Their study specifically compared amorphous IZO (a-IZO) with polycrystalline ITO (c-ITO) as rear transparent electrodes in superstrate-architecture perovskite solar cells. The transparent perovskite solar cells (T-PSCs) were fabricated using a n–i–p device stack, composed of c-ITO or a-IZO rear transparent electrode, a molybdenum(VI) oxide (MoO₃) buffer layer, Spiro-MeOTAD hole transport layer, a perovskite absorber, a tin(IV) oxide (SnO₂) electron transport layer, and a fluorine-doped tin oxide (FTO) front electrode. This device architecture enabled a direct comparison of the performance and interface characteristics associated with each electrode material.
The study showed that a-IZO-based cells achieved superior efficiency - 18.22% compared to 15.84% for c-ITO - while avoiding common issues like delamination. Crucially, the researchers found that the lower efficiency of c-ITO devices was due to interfacial defects at the MoOx/transparent-electrode interface, which limited performance. In contrast, a-IZO minimized these defects and resulted in higher device stability.
Enhanced mobility in the a-IZO films contributed to greater near-infrared transmittance, along with low sheet resistance, high carrier mobility, and low surface roughness. These combined properties offer better electrical and optical characteristics for transparent and tandem perovskite solar cells.
Overall, the shift from c-ITO to a-IZO is supported by these advantages, pointing to the broader use of a-IZO electrodes in advanced optoelectronic and photovoltaic applications.
