Phase transitions in the organic semiconductor dipropylamine tetracyanoquinodimethane: DPA TCNQ2

Abstract

Dipropylamine tetracyanoquinodimethane, DPA TCNQ2, is by stoichiometry a 1:2 organic salt giving rise to a [Formula: see text] filled band quasi one dimensional electronic system. Conductivity measurements indicate the presence of at least three phase transitions. A dominant transition at 215 K shows simultaneous large discontinuities in both electric and magnetic properties. Infrared measurements suggest a structural change at 215 K related to conduction electron–molecular vibration interactions in view of the appearance of Ag TCNQ modes in the infrared spectrum. Deuteration of the donor [Formula: see text]bond lowers the main transition temperature by 5 K but maintains the same physical properties as in the nondeuterated compound.