ELECTRICAL AND PHOTOELECTRICAL PROPERTIES OF POLY(PHENYL AZOMETHINE FURANE) THIN-FILMS DEVICES

Poly(phenyl azomethine furane) (PPAF), a conjugated system of poly-Sch iff base was synthesised by condensation of p-aminobenzene with furane -2-aldehyde. Oxidative polymerization was conducted at 0-5 degrees C t emperature, and the polymer formed was found to be soluble in common o rganic solvent. Optical properties were studied in the UV-visible-IR r egion. Electrical and photo electrical properties of Al/PPAF/ITO and A g/PPAF/ITO sandwich devices were investigated by measuring the steady state photocurrent resulting from illumination. The device Al/PPAF/ITO shows a Schottky barrier at the Al-PPAF interface and ohmic contact a t ITO-PPAF interface. The device Ag/PPAF/ITO shows ohmic contact at bo th interfaces. This behaviour has been explained in terms of P-type co nductivity of the PPAF and the formation of a Schottky barrier with th e low work function electrode and ohmic contact with the higher work f unction electrode. Under low forward bias voltage (ITO positive) ohmic conduction is observed while at higher voltage there is space charge- limited conduction (SCLC). The dependence of the photo short-circuit c urrent on illumination intensity was discussed in detail. The C-V char acteristics of both devices have also been analysed.