Growth and Structural Characterization of Doped Polymorphic Crystalline MgPc as an Organic Semiconductor

Leon Hamui,Cecilio Álvarez-Toledano,Arturo Ponce,Jose Luis Reyes-Rodriguez,María Elena Sánchez-Vergara,Rocio Sánchez-Ruiz

doi:10.3390/cryst10060495

Abstract

The doping and crystallization of the molecular semiconductor formed from the magnesium phthalocyanine (MgPc) and 1-(4-Methoxyphenyl)-2,2,6,6-tetramethyl-5-phenylhepta-3,4-dienedioic (MTPDA) acid was carried out in this work. The crystals obtained were characterized by using transmission electronic microscopy (TEM), Raman spectroscopy, and X-Ray diffraction (XRD), to later evaluate their optical behavior. Raman, IR, and UV–Vis results indicate that the MgPc has been doped with the MTPDA. A uniform material layer with particles is observed as a result of a two-stage process, nucleation and growth. The polycrystalline films are constituted by a mixture of α and β phases with crystalline sizes of ~7 nm, 14 nm, and 20 nm average sizes. The films exhibit a preferred orientation along the [001]. The MTPDA doping does not have an important effect on the molecule planar distances indicating that the MTPDA molecule is among the equivalent MgPc plane direction. A transparent region with a minimum at 483 nm is observed, also a B-band at 337 nm and a Q-band transition with a high-energy peak around 639 nm, and a low energy peak around 691 nm.

Highlights

IntroductionNew alternatives have been developed for conventional electronic devices made up mainly by inorganic semiconductors, i.e., those devices fabricated based on silicon and germanium technologies
New alternatives have been developed for conventional electronic devices made up mainly by inorganic semiconductors, i.e., those devices fabricated based on silicon and germanium technologies.The need of new materials comes from the high costs that represent the production, either bottom-up and top-down processing, of standard electronic devices in nanotechnology due to the complexity of conventional fabrication methods
Crystals of magnesium phthalocyanine doped with 1-(4-methoxyphenyl)-2,2,6,6-tetramethyl-5phenylhepta-3,4-dienedioic acid were deposited

Summary

Introduction

New alternatives have been developed for conventional electronic devices made up mainly by inorganic semiconductors, i.e., those devices fabricated based on silicon and germanium technologies. The attractive forces between aromatic rings are mainly π-π interactions and hydrogen bonds These interactions facilitate the formation of different crystalline phases, which are highly dependent on the substituents in the macrocycle and the molecules orientation and spacing [9,14]. Each of the crystalline arrangements has its characteristic opto-electronic behavior, since the orientation of molecules modify the π transitions and, the Q and Soret (B) bands [19] It has been identified five transition bands for the MPcs, labeled as Q, B, N, L, and C bands [20]. To generate a probable improvement on the optoelectronic properties of the MgPc, the 1-(4-Methoxyphenyl)-2,2,6,6-tetramethyl-5-phenylhepta-3,4-dienedioic acid was used dope the compound within the thin films.

Materials and Methods

Results

Conclusions