Thermogravimetric, Photoluminescence and Atomic Force Microscopy Characterization of Metal-Loaded Polyaniline and Metal Sulfide Nanostructures
Author : Nidhi V Nalkande, RP Pawar and Gopalkrushna H Murhekar
Abstract :
In this work, the thermal, optical, and nanoscale surface properties of pristine polyaniline (PANI), metal-loaded PANI nanocomposites (PANI–Cd, PANI–Cu, PANI–Ni), and metal sulfide nanostructures (CdS, CuS, NiS) synthesized at different precursor concentrations are systematically investigated using Thermogravimetric Analysis (TGA), Atomic Force Microscopy (AFM), and Photoluminescence (PL) spectroscopy. TGA reveals multi-step degradation behavior in PANI and enhanced thermal stability upon metal incorporation, with PANI–Ni and NiS demonstrating the highest half-decomposition temperatures and activation energies. Metal sulfides exhibit single-step high-temperature decomposition, with NiS being the most thermally stable. AFM studies show a clear evolution from amorphous granular morphology in pristine PANI to compact, highly organized nanoscale domains in metal-loaded PANI and crystalline clusters in CdS and CuS, accompanied by increased surface roughness. PL spectra of CdS and NiS nanostructures at various concentrations display broad, asymmetric emission bands in the 1.4–2.5 eV range, dominated by defect-mediated transitions involving shallow and deep trap states (E1, E2, E3). The combined results demonstrate that metal incorporation and precursor concentration significantly tune the thermal, morphological and optical behavior of the nanostructures, making them promising for applications in optoelectronics, catalysis, sensing, energy storage, and antimicrobial systems.
Keywords :
Polyaniline, CdS, NiS, CuS, Thermogravimetric Analysis, Atomic Force Microscopy, Photoluminescence, Nanocomposites, Defect states.
