The application of Langmuir-Blodgett films of a new asymmetrically substituted phthalocyanine, amino-tri-tert-butyl-phthalocyanine, in diodes and in all organic field-effect-transistors

Amino-tri-tert-butyl-phthalocyanine (AmBuPc) was used as the semiconductor thin layers in model Schottky diode and all organic field-effect transistor (OFET). The diode cell showed a rectifying effect with a rectification rat io of 60 at +/-3.2 V. The ideality factors were 1.38 in the low voltage reg ion and 3.09 in the high voltage region, respectively. The results of OFET proved that AmBuPc Langmuir-Blodgett (LB) films could be used as the semico nducting layer of OFET, and the OFET could function as a p-channel accumula tion device. From the OFET electrical characteristics, the channel carrier mobility is calculated to be about 5.2 X 10(-6) cm(2) V-1 s(-1), which is h igher than that of vacuum-deposited film OFET (7.8 X 10(-7) cm(2) V-1 s(-1) ) utilizing the same polymer. This phenomenon can be explained as the highl y ordered structure of AmBuPc molecules in the LB films. This suggests that a wide conduction channel is able to form in this all organic device, whic h provides a new method to simplify the fabrication process of OFET and imp rove their properties. (C) 1999 Elsevier Science S.A. All rights reserved.