Abstract
Organic light-emitting diodes (OLEDs) represent a rapidly developing class of optoelectronic devices widely employed in display and lighting technologies. The continuous improvement of OLED performance critically depends on the development of organic materials capable of efficient charge transport, effective exciton utilisation, and long-term operational stability. Among nitrogen-containing heterocyclic compounds, triazoles have emerged as versatile scaffolds in materials science due to their exceptional electron-transporting properties. Structurally, triazoles are classified as 1,2,3-triazoles and 1,2,4-triazoles, both of which can accommodate diverse substituents around the core, enabling fine-tuning of their electronic and photophysical characteristics. These features make triazole derivatives and their derivatives highly suitable as electron-transporting materials, hosts and emitters in optoelectronic applications, including OLEDs, photovoltaics and sensors. The incorporation of triazole units allows for efficient charge transfer, enhanced thermal and chemical stability, and improved device performance. This review highlights the structural aspects and functional roles of triazole-based compounds in electron-transporting systems. The application of triazole-based compounds as hosts and emitters provides a comprehensive perspective on their potential for next-generation optoelectronic devices.