Bulk and Surface modifications for Wide Bandgap Perovskite Solar Cells

The accelerating impact of climate change and global pollution has led to a rapidly increasing demand for renewable energy sources. Among these, photovoltaic energy has emerged as a leading candidate for achieving sustainability and energy efficiency. However, the development of efficient and stable wide bandgap perovskite materials for use in silicon-perovskite tandem solar cells for even higher power output remains a significant challenge. These materials are critical because defects in the perovskite bulk and at interfaces can increase charge carrier recombination, thereby limiting device performance. This research addresses this challenge by optimizing the wide bandgap perovskite optoelectrical properties via bulk and interfacial modulation. The wide bandgap halide perovskites were fabricated via a vapor-solution hybrid approach. Bulk additives and surface passivating materials are investigated to enhance the perovskite quality and eventually device performance. Additionally, a morphology study was conducted on silicon cells to better understand deposition conditions of perovskite layer stack on textured silicon substrates, with the goal of applying these insights to develop more efficient perovskite/silicon two-terminal tandem solar cells. For characterization, scanning electron microscopy was employed to analyze sample morphology, while a solar simulator provided figures of merit for the solar cells. Photoluminescence measurements further elucidated the bandgap properties of the materials. 19\% efficiency was obtained for inverted p-i-n 1.67 eV perovskite solar cells based on a fully scalable cell architecture. The incorporation of additive materials and interlayers showed considerable potential in enhancing device efficiency and overall performance. However, further research is necessary to fully understand the underlying mechanisms and optimize these additives for broader application. Future work will focus on refining these techniques, determining optimal additive concentrations, and conducting additional characterization to achieve reproducible enhancement in device performance.