Used in the fabrication of perovskite-based optoelectronic devices, particularly light-emitting diodes (LEDs) and solar cells. It helps stabilize the perovskite structure and improves film quality by passivating defects at grain boundaries. The hexylammonium cation contributes to better moisture resistance and enhanced phase stability, which increases device efficiency and operational lifetime. It is also employed in solution-processed thin films for tunable green to blue emission in LEDs.