Used as a hole-transporting material in organic light-emitting diodes (OLEDs), particularly in blue-emitting devices due to its high triplet energy and thermal stability. Its spirobifluorene core provides a rigid structure that enhances morphological stability and prevents crystallization in thin films. Commonly employed in phosphorescent and thermally activated delayed fluorescence (TADF) OLEDs to improve device efficiency and lifetime. Also utilized in perovskite solar cells as a hole-transport layer, contributing to high open-circuit voltage and power conversion efficiency.