Polyaniline nanoparticles: A study on its structural, optical, electrochemical properties along with some possible device applications

• Published in: Synthetic metals Vol. 290; p. 117152
• Main Authors: Rather, Mudasir Hussain, Mir, Feroz A., Ullah, Faheem, Bhat, Mohd Asif, Najar, Fayaz A., Shakeel, Gowher, Shah, Ashiq H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2022
• Subjects: Diode; Electrochemical; Optical; Photocatalyst; Polyaniline; Sensor; Diode; Polyaniline; Photocatalyst; Optical; Electrochemical; Sensor
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2022.117152

In this report, the Polyaniline (PANi) nanoparticles (NPs) were synthesized by in-situ polymersation method. These PANi NPs were characterized by various standard techniques. The crystal structure study were done by Powder X-Ray diffraction (XRD) technique and confirms its amorphous structure. Scanning Electron Microscopy (SEM) images showed that this material shows micron size microfibers made up of NPs with less porosity. The Fourier Transform Infrared (FT-IR) spectroscopy confirms PANi NPs formation and dominant vibrations corresponding to its Quinone and benzene rings were very much visible in the data. From the UV-Visible spectroscopy data, the absorption data confirms the transitions related to its Quinone ring and pyran rings. The optical band gap was estimated to be around 2.47 eV and this material follows indirect allowed transition. From the Photoluminescence (PL) data, it showed various emission line in visible region after exciting it by various UV photons. PL data also confirms defects and bipolaron formation in it. The Cyclic Voltammetry (CV) of PANi was also studied and the parameters like specific capacitance (CP), energy density (ED),and power density (PD) were estimated. For the current material, the value of CP, ED, PD were calculated to be around 72F/g, 144 J/cm3, and 0.9 W/m3 respectively. Further the energy bands like highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of this material was determined by employing CV and the value obtained goes well as calculated by optical absorption techniques. The Electrochemical Impedance Spectroscopy (EIS) carried on PANi NPs (under different studied conditions) also reveals the formation of defects or the play of existing defects with the incident light photons. From practical application point of view, a diode like structure of this material was also fabricated. To this diode, current-voltage (I-V) and dielectrics spectroscopy measurements was carried out in dark and with photons of various wavelengths. Under different measured conditions, the I-V characteristics showed non-linear behavior. Under above experimental situations, the various parameters related with I-V characteristics were also calculated. Also this material show self-powered phenomenon, one of the essential conditions for photo detector/sensor applications. Further this device was also subjected to transient measurements. The reverse recovery time for this diode was calculated to be around 3.04 μs. The capacitance and loss studied on this device shows well dispersion with applied frequency. The observed capacitance and loss also show some changes in presence of different color of photons. The experimental data and overall properties shown by this material correlate with each other. The various properties shown by this material projects it a good candidate for future flexible optoelectronics applications. [Display omitted] •Polyaniline (PANi) nanoparticles (NPs) are prepared by chemical oxidative polymerization method.•The successful synthesis of PANi NPs was confirmed by XRD, FT-IR, Uv-Vis spectroscopy data.•For this material, optical band gap was found to be 2.47 eV with indirect allowed transition.•A diode of this material was also designed and characterized under different photo exposure conditions.•The designed device show self generation phenomenon and which can be well exploited for light sensing applications.