Tuning the Electrical and Thermoelectric Properties of Phthalocyanine and Metallo-Phthalocyanine Molecular Junction

Abstract

In this work, a comparative study is presented that analyses the electrical and thermoelectrical properties of free base-Phthalocyanine (Bare-Pc) and Metallo-Phthalocyanine (MPc) molecule sandwiched between gold electrodes. The study investigates the transmission and conductance characteristics of Bare-Pc without central metal ion and with different transition metal ions at the centre of (Pc) such as (Mn, Co, Ni, and Zn) in two different molecular configurations, cis and trans. The results reveal that the conductance changed by varying the transition metal-centre in the order of Co > Ni > Zn in trans, and closely similar pattern Co > Ni > Mn in cis with higher values in trans configuration. This reflects the correlation between the spin-dependent transport properties with the transition metal-centre type and the molecular structure. Further, thermoelectrical properties such as thermal conductance (k), Seebeck coefficient (S) and figure of merit (ZT) are investigated. It was found that (k), (S) and (ZT) have higher values in case of trans configuration for Co-Pc, Ni-Pc and Zn-Pc structures. Thus, by varying the transition metal-centre type and the molecular configuration of (Pc) molecule, transport properties can be tuned to produce a good value of the transmission and electrical conductance, thermal conductance, Seebeck coefficient, and figure of merit of the (Pc) molecular junction for potential high conductance and efficient thermoelectric applications.