Extended Conjugation in Polyaniline Like Structure Prepared by Plasma Polymerization Suitable for Optoelectronic Applications

Abstract

Plasma polymerization of aniline is carried out in a radiofrequency plasma reactor and the effect of polymerization time is examined in the structural, optical and optoelectronic properties of deposited films. Conjugated structures of polyaniline like films are obtained with unique and broad optical absorption band in the ultraviolet and entire visible region. The width of the absorption band increases and hence the optical band gap decreases with polymerization time. The optical constants are extracted by Swanepoel method and the optical dispersion parameters are determined by employing the WempleDiDomenico single oscillator model. The films exhibit similar thermal stability in air and argon atmosphere in the region of interest for optoelectronic applications. The photoluminescence study suggests, like the chemically synthesized polyaniline, the benzenoid units to be responsible for fluorescence. The fluorescence peaks due to defect states confirm the formation of spectroscopic units in the plasma polyaniline films.

Controlling the flux of reactive species: a case study on thin film deposition in an aniline/argon plasma

“…The band around 3362 cm −1 can be associated to N–H vibrations 8 , 25 , 31 , 36 , 48 . The next two bands around 3020 cm −1 and 2930 cm −1 can be referred to C–H stretching modes in aromatic structures 48 − 50 or to C–H stretching modes related to aliphatic compounds 8 , 31 , 49 , 50 . The peak around 2217 cm −1 can be attributed to C≡N bonds 49 − 51 .…”

“…The next two bands around 3020 cm −1 and 2930 cm −1 can be referred to C–H stretching modes in aromatic structures 48 − 50 or to C–H stretching modes related to aliphatic compounds 8 , 31 , 49 , 50 . The peak around 2217 cm −1 can be attributed to C≡N bonds 49 − 51 . At 1496 and 1600 cm −1 the typical absorption peaks for C=C stretching of benzenoid and quinoid rings are observed 8 , 25 , 49 , 52 , 53 .…”

Controlled deposition of plasma‐polyaniline thin film by PECVD: Understanding the influence of aniline to argon ratio

“…In Table 1, the spectra of all positively ionized aniline fragments; that is, the energy-integrated spectra of positive ions with a mass to charge ratio of 26,27,28,50 Here again, the measurement starts 15 min after plasma ignition, when the plasma has reached a steady state. As displayed in Table 1, the ratio of ionized fragments to C 6 H 7 N + ions drops drastically, from 21.5 to 0.25 when the aniline vapor flow is increased from 0.2 to 3 sccm.…”

“…[42] For instance, it was shown to cite a few examples over many, that composite materials such as CNTs coated with a conformal polyaniline coating are promising for Li-ion batteries cathodes [43] or for the electrodes of supercapacitors. [44,45] Although many studies have been conducted on the production of various conductive polymers by PECVD, such as polyaniline [46][47][48][49][50][51][52][53][54][55] or polypyrrole, [56][57][58][59][60][61][62] most of these studies have mainly focused on the material characterization rather than on the analysis of the discharge. Plasmas containing organic molecules, such as aniline or pyrrole, are characterized by a large variety of reactive/ ionized species, leading to discharges with tremendous complexity.…”

Poly(allylamine) plasma polymer coatings for an efficient retention of Ni(II) ions by ultrafiltration membranes

“…Plasma polymerization has also received great attention since it is an environmentally clean technique (solvent‐free) which can provide pinhole‐free, ultra‐thin films with different functional groups on various substrates . The produced films can further be used for many applications including anticorrosion, sensors, optoelectronics, fuel cells, textiles, or biomedical applications …”