Passivation of trap states in unpurified and purified C_(60) and the influence on organic field-effect transistor performance

摘要

We investigate trap-state passivation by addition of ultra-low amounts of n-dopants in organic field-effect transistors (OFET) made of as-received and purified fullerene C_(60). We find a strong dependence of the OFET threshold voltage (V_T) on the density of traps present in the layer. In the case of the unpurified material, V_T is reduced from 17.9 V to 4.7 V upon trap passivation by a dopant:C_(60) ratio of ～10~(-3), while the I_(on/off) current ratio remains high. This suggests that ultra-low doping can be used to effectively compensate impurity and defect-related traps.