Strategic TCO selection: Insights from MTO/TCO bilayer coupling analysis

Doped metal oxides are versatile materials with diverse applications, particularly as transparent conducting oxides (TCOs) and window layers in solar cells. While TCOs exhibit electronic conduction, window layers act as semiconductors. Despite significant advancements in the study of metal-semiconductor junctions, the interplay between homologous doped metal oxides fulfilling these dual roles remains largely unexplored. Magnesium-doped tin oxide (MTO), recognized for its wide bandgap, has emerged as a promising window layer material. However, the optoelectronic coupling between MTO and various TCOs remains insufficiently understood. This study investigates three MTO/TCO bilayer configurations: MTO/FTO (fluorine-doped tin oxide), MTO/AZO (aluminum-doped zinc oxide), and MTO/ITO (indium tin oxide). Through comprehensive structural, chemical, morphological, optical, and electrical characterizations, the influence of coupling MTO with different TCOs was evaluated. The results provide valuable insights into the mutual interactions between these materials, guiding the selection of optimal TCO. These findings hold promise for improving the efficiency and stability of next-generation photovoltaic devices.