Understanding Charge Transport in Endohedral Fullerene Single-Crystal Field-Effect Transistors

The encapsulation of nitrogen within C 60 forms nonmetallic endohedral fullerene [email protected] 60 . Previous calculations show that the encapsulated nitrogen may favor more efficient charge injection and transport under external electric fields when compared to C 60, suggesting that [email protected] 60 may be a promising candidate for applications in organic electronic devices. However, owing to difficulties in both synthesis and purification, the potential application of [email protected] 60 under external electric field has not been previously studied experimentally and its intrinsic charge-transport mechanism remains unknown, which hinders more wide applications of endohedral fullerenes in organic electronic devices. Here, we demonstrate the field-effect study and photodetection applications of solution-grown [email protected] 60 single crystals. Organic field-effect transistors (OFETs) based on them exhibit electron mobilities up to 2.23 cm 2 V –1 s –1 . Furthermore, the electrical properties show a favorable bandlike charge-transport mechanism from 180 to 300 K, and photodetectors based on them yield a highly sensitive photoconductive property under near-infrared illumination with a responsivity of 177.3 A W –1 . This study, which outlined the intrinsic charge-transport properties of [email protected] 60, should not only enable significant advancements for the high-mobility n-type OFETs and highly sensitive photosensing applications but also provide a reference for studying the fundamental physics of endohedral fullerenes.