Ms. Roy et Gd. Saxena, D",manmeeta,"sharma, Doping effect of viologen on rectification, charge transport processes andphotovoltaic properties of furazano (3,4-b)piperazine thin film device, J MAT S-M E, 12(1), 2001, pp. 45-50
The electrical and photoelectrical properties of a sandwich junction device
based on allyl viologen (AV)-doped furazano (3,4-b)piperazine (FP) having
structure ln/AV : FP/ITO have been reported. A significant enhancement in t
he rectification, dark conductivity and photovoltaic response has been obse
rved in AV-doped FP devices compared with undoped FP devices. The present c
ommunication deals with the charge transport mechanism and photogeneration
process in ITO/AV doped FP/ln Schottky devices. The J-V characteristics rec
orded in the dark show a rectification effect due to the formation of a bar
rier at the AV-doped FP/ln interface. Impedance spectroscopy has been used
to study the charge transport mechanism for AV-doped FP and its interface w
ith ln. The bulk and junction resistance along with capacitance were determ
ined by analyzing their contribution at an individual level. Doping imparts
an improvement in photoresponse of FP as well as an abundance of photoexci
ted species at the interface. (C) 2001 Kluwer Academic Publishers.