The Hole Transport Characteristics of 1, 4, 5, 8, 9 and ll-Hexaazatriphenylene-Hexacarbonitrile by Blending

The hole transport characteristics of molecule blends of 1, 4, 5, 8, 9 and 11-hexaazatriphenylene-hexacarbonitrile （HAT-CN）： N,N＇-di（naphthalene-l-yl）-N,N＇-diphenyl-benzidine （NPB） and HAT-CN： 4,4＇-cyclohexylidenebis[N,N- bis（4-methylphenyl）benzenamine] （TAPC） with various NPB and TAPC mixing concentrations （5 90wt%） are studied. When the concentration is in the range of 5-80wt%, it is found that the hole conductions in the two blends are space-charge-limited current （SCLC） with free trap distributions. The current-voltage characteristics of the two blends show SCLC with exponentiM trap distributions at the concentration of 90wt%. The hole mo- bilities of the two blends are very close （10^-4-10^-3 cm2 V^-1 s-X ）, the dependence of electric field and temperature can be described by the modified Poole-Frenkel model. The hole mobility and activation energy of the two blends depending on concentration are similar.