Applications of PANI Thin Films

Polypyrrole, polythiophene, and PANI are inherently conducting polymers (ICPs), which show electrical properties just like metals and semiconductors. Aniline has low cost, so it makes PANI the least expensive and thermally stable from all ICPs. PANI is conducting in nature, but due to its less solubility and melting processability, it has not much attention for commercial purposes. PANI might be used for commercial purposes following by some additional improvements. It can be synthesized by electrochemical and chemical oxidative polymerization. PANI thin films can be used in the detection of gases as gas sensors, chemical and biological sensors, optical pH sensors, etc. These films can also be used in supercapacitors, electrochromic devices, solar cells, dye-sensitized solar cells, rechargeable batteries, electrochemical filter, protection of metal surface from corrosion, etc. PANI thin films can also be used in biological applications such as antimicrobial properties, and the various researchers across the globe have the most widely studied tissue engineering applications.

Physiochemical Properties of PANI Thin Films

Good environmental stability, a high degree of processability, and interesting redox properties associated with its chain heteroatom due to this polyaniline (PANI) have been one of the most extensively studied conducting polymers from the last few years. The chemical and electrochemical processes can be used to synthesize PANI. This chapter mainly focused on physiochemical properties of PANI thin films such as conducting properties, optical properties, magnetic properties, electrical and dielectric properties, mechanical properties, crystalline nature, capacitive properties, sensing properties, charge-discharge properties, thermoelectric properties, redox properties, antioxidant properties, anticorrosion properties, etc.

High-Throughput Synthesis, Deposition and Characterization Techniques

Polyaniline (PANI) has an exclusive representation probably owing to the fact that it has new applications in several fields of nano-technology. It is known for its straightforward synthesis process, high environmental stability and it can be easily doped by different acids. This chapter deals with the synthesis of PANI by several methods in which oxidative polymerization is the simplest and the most highly studied process. The synthesized PANI thin films can be deposited on different substances by a number of chemical and physical-based methods. These PANI thin films have been characterized by different techniques. FTIR and Raman spectroscopy used for structural analysis of synthesized PANI thin films while the crystalline nature determined by X-ray diffraction (XRD). Similarly, SEM, TEM, and AFM have been used for surface analysis of PANI thin films. The thermal and optical characteristics of PANI thin films studied by TGA and optical absorbance spectroscopy, respectively. The cyclic voltammetry (CV) curve gives information about the electrochemical reaction rate and the redox potential of PANI thin films.

Effects of Doping and Post-Treatments on PANI Films

It is well known that the sample preparation, experimental measurement, and technique have played a vital role in empirical research work. In this chapter, the detailed discussions on the doping and various post-treatments on the PANI thin films have been made. The in-depth studies on gold, silver, aluminum, lithium, HCl, and camphor sulfonic acid (CSA) doped PANI nanocomposites and thin films have been undertaken in this chapter, followed by discussing the effect of post-annealing treatment and ion reaction medium. The impact of different doping and post-treatment on the properties of PANI films viz. microstructural, optical-electrical, thermal, etc., have been analyzed herein. The structural and optoelectrical properties of PANI films and its nanocomposites have also been discussed in which metal-nanoparticles inserted PANI films achieve particular consideration due to its relatively thought-provoking non-linear optical properties.

Theoretical Aspects of Thin Film Solar Cells

The theoretical background is an essential part of any experimental work, and unless the understanding of proper theory associated with any experiment, the explanation of results not considered as accomplished. This chapter highlights the related approaches for calculating and explaining the effects of different parameters of the proposed studies. The concepts applied to investigate the microstructural and optoelectrical properties of semiconducting polymer films, Schottky, and heterojunction junctions are discussed and explained.

Conclusions and Future Aspects

Polyaniline (PANI) is one of the common and extensively explored conducting polymers due to its excellent electrochemical and electrical properties. PANI thin film is an emerging area of research owing to its various applications in the field of solar cell technologies, drug delivery, organic light emitting diodes, field-effect transistors, sensors, electrochromic displays, etc. This chapter is devoted to the conclusions and future aspects of the undertaken studies in this book. This book has eight chapters that comprise the discussion of synthesis, deposition and characterization techniques, physiochemical properties, and applications of PANI thin films.

PANI Thin Films for Solar Cells

After the breakthrough of conducting polymers, an incredible interest has been paid to integrate them in electronic component fabrication as an alternative to metals. Polyaniline is the most extensively studied material due to the ease of synthesis, better environmental stability, and enormous scope to modify its properties for solar cell applications. The electrical conductivity of PANI can be altered according to the need for the application where electronic devices made of conducting polymer composites are significantly dependent on the dielectric properties of the materials. Therefore, this chapter has been dedicated to the low-frequency AC conduction and dielectric studies of conducting PANI followed by having PANI thin films as efficient donor or acceptor bulk heterojunction layer to the hybrid solar cells.

Introduction of PANI Thin Films

In all conducting polymers (CPs), polyaniline (PANI) is one of the most thoroughly studied CPs. An essential feature of PANI is that its repeating units have two different moieties in different weights: oxidized and reduced state. In light of this element, PANI might be doped to get new molecular structures with various properties. It is considered as a (p-type) material, since it has excellent mechanical flexibility and environmental stability, and its conductivity could be controlled with acid/base (doping/undoping), it has potential applications in numerous fields, for example, lightweight battery electrodes, electromagnetic shielding devices, anti-corrosion coatings, and sensors. This chapter is focused on PANI as a leading polymer and brief synthesis of PANI thin films by the diverse strategies pursued by various applications in different fields.