New Development of Membrane Base Optoelectronic Devices

Abstract

It is known that one factor that affects the operation of optoelectronic devices is the effective protection of the semiconductor materials against environmental conditions. The permeation of atmospheric oxygen and water molecules into the device structure induces degradation of the electrodes and the semiconductor. As a result, in this communication we report the fabrication of semiconductor membranes consisting of Magnesium Phthalocyanine-allene (MgPc-allene) particles dispersed in Nylon 11 films. These membranes combine polymer properties with organic semiconductors properties and also provide a barrier effect for the atmospheric gas molecules. They were prepared by high vacuum evaporation and followed by thermal relaxation technique. For the characterization of the obtained membranes, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were used to determine the chemical and microstructural properties. UV-ViS, null ellipsometry, and visible photoluminescence (PL) at room temperature were used to characterize the optoelectronic properties. These results were compared with those obtained for the organic semiconductors: MgPc-allene thin films. Additionally, semiconductor membranes devices have been prepared, and a study of the device electronic transport properties was conducted by measuring electrical current density-voltage (J-V) characteristics by four point probes with different wavelengths. The resistance properties against different environmental molecules are enhanced, maintaining their semiconductor functionality that makes them candidates for optoelectronic applications.

Fabrication of Hybrid Membranes Containing Nylon-11 and Organic Semiconductor Particles with Potential Applications in Molecular Electronics

“…All the signals that corresponding to the particles were observed, and the signals of Nylon-11 were also observed. From this last observation, the bands at 3306 and 3083 ± 2 cm −1 correspond to the stretching vibrations for N-H, and the band around 1654 ± 3 cm −1 is assigned to the C=O vibrations in the polymeric matrix [9]. The results obtained suggest that, during the manufacture of the membranes, there was no degradation of their components and no signals corresponding to impurities were generated during the fabrication of the membranes, which indicates that the high-vacuum evaporation method generates a high-purity membrane.…”

“…Additionally, due to the lower free energy per unit volume of the sphere, the nuclei of the membrane deposited on the substrate resembles a geometry (see Figure 3c,d) that, when it grows, is maintained as the deposit advances and the membrane is formed. The growth and nucleation process generated by ONs particles depends directly on the structure of the molecular semiconductor (ONs-1 and ONs-2) and the thermic gradient between the substrate and the system ONs/Nylon-11 [9]. Thermal relaxation is also worthy of discussion, as during heating Nylon-11, fibers undergo an elongation that allows ONs to penetrate the matrix of the membrane.…”

“…The peak of around 1.8 eV (~680 nm), which is associated with the π*-π relaxation transitions of the molecular semiconductor, is red-shifted for the membrane. This is related to the π-π* stacking of the conjugated Pc as the semiconductor particles are introduced in the Nylon-11, which infers molecule aggregation [9].…”

“…Polyundecanolactam (Nylon-11: [-NH(CH 2 ) 10 CO-]n), Zinc phthalocyanine (ZnPc: C 32 H 16 N 8 Zn), Zinc 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,hexadecafluoro-29H,31H-phthalocyanine (F 16 ZnPc: C 32 F 16 N 8 Zn) and dibenzotetrathiafulvalene (DBTTF: C 14 H 8 S 4 ) were acquired from the commercial supplier (Sigma-Aldrich, Saint Louis, MO, USA). Due to their purity certificate, no additional purification was needed.…”

“…Unfortunately, the performance of electronic devices is compromised under environmental conditions, so protection against degradation is necessary. Polymeric membranes are an exceptional option for isolating MPcs without affecting their charge transport properties [9]. Nylon-12 is known to be a polymeric biomaterial, and is commonly used as a cartilage replacement.…”