Comparative Study of Conduction Mechanisms in Disodium Phthalocyanine-Based Organic Diodes for Flexible Electronics

Abstract

In the current work, flexible diodes with flat heterojunction and dispersed heterojunction architecture were manufactured with to study the behavior of thin films of disodium phthalocyanine (Na2Pc). The thin film devices, using the electronic acceptor tetracyano-π-quinodimethane (TCNQ), were fabricated by high-vacuum thermal evaporation with annealing post-treatment in order to optimize their behavior. Theoretical calculations based on density functional theory (DFT) with dispersion force analysis were carried out in order to simulate molecular interactions and to establish the nature of the weak interactions between the Na2Pc and TCNQ fragments. In the optimized structure of the coupled Na2Pc-TCNQ, the electronic relationship between phthalocyanine and TCNQ was observed to be through hydrogen bonds with bond lengths of 2.94 and 3.13 Å. Dispersed heterojunction device current density values were considerably larger than those of the flat heterojunction device. Barrier heights of 1.024 and 0.909 eV and charge mobilities of 10−10 and 10−9 m2/Vs for the flat heterojunction device and the dispersed heterojunction device, respectively, were observed. A small effect was observed on the electrical properties by thermal annealing on the flat heterojunction device. The threshold voltage decreased from 1.203 to 1.147 V and φb decreased by 0.001 eV.

A Comparative Study of the Semiconductor Behavior of Organic Thin Films: TCNQ-Doped Cobalt Phthalocyanine and Cobalt Octaethylporphyrin

“…The objective of this work is to compare the effect of CoPc and CoOEP (cobalt(II) octaethylporphyrine) as dopants, when using the electronic acceptor tetracyano-π-quinodimethane (TCNQ) as host/matrix. TCNQ, as previously reported by some of the authors of this work [40,41] has interesting electrical properties, due to its low dimensionality and energy-band formation, as well as its ability to yield or accept electrons at a low energy cost, which results in a partially occupied higher energy band [40,41]. By means of DFT (density-functional theory) calculations, the possible interaction between the cobalt macrocycles and the TCNQ was obtained, as well as the HOMO-LUMO orbitals and the theoretical bandgap of each system.…”

Electrical conduction mechanism and dielectric relaxation of bulk disodium phthalocyanine

“…At room temperature, the value of W m has been obtained from the slope of the linear part in the graph 1 s [ ] versus T illustrated in figure 5. The W m value was found to be equal to 0.43 eV, this value is approximately equal to the quarter optical energy gap of Na 2 Pc [32]. This indicates that the predominating conduction mechanism in the Na 2 Pc compound is a single polaron hopping mechanism.…”

Electrochemically Deposited Zinc (Tetraamino)phthalocyanine as a Light-activated Antimicrobial Coating Effective against S. aureus

“…For many years, phthalocyanines (Pcs) have been mainly investigated as promising candidates for application in (opto)electronics. Until recently, Pcs in a free-base form or with a central metal have been used in organic photovoltaic devices (OPVs) [ 15 , 16 , 17 ], organic light-emitting diodes (OLEDs) [ 18 , 19 ], or gas sensors [ 20 , 21 , 22 ]. Their effectiveness as photoinitiating systems [ 23 , 24 ] and photosensitizers [ 25 , 26 ] has also been reported.…”