Synthesis, characterization, photophysical, thermal and electrical properties of composite of polyaniline with zinc bis(8-hydroxyquinolate): a potent composite for electronic and optoelectronic use

Abstract

A composite of polyaniline (PANI) with the metal complex zinc bis(8-hydroxyquinolate) [Zn(8HQ)₂] is synthesized by an in situ polymerization technique. The metal complex and the synthesized PANI–[Zn(8HQ)₂] composite are characterized by EDX, FTIR, XRD and TG analysis. FESEM analysis shows distinct morphological features of PANI and the PANI–[Zn(8HQ)₂] composite. XRD shows the crystalline nature of the metal complex, which is retained in the PANI–[Zn(8HQ)₂] composite. TG reveals the higher thermal stability of the PANI–[Zn(8HQ)₂] composite as compared to pure PANI. DSC shows an increase in the glass transition temperature of the PANI–[Zn(8HQ)₂] composite, which indicates its rigid nature. UV-visible spectral characterization confirms the red shift of polyaniline upon doping with the zinc complex. The metal complex exhibits excellent photophysical properties, good thermal stability and conducting behavior. The fluorescence intensity of the PANI–[Zn(8HQ)₂] composite is found to be much higher than that of pure PANI. The relative fluorescence quantum yield of the PANI–[Zn(8HQ)₂] composite is a few orders of magnitude higher than that of pure PANI. The conductivity of the PANI–[Zn(8HQ)₂] composite is greater than that of the pure PANI, as detected by a four probe method, and IV characteristics suggest semiconducting and conducting behavior of the pure PANI and PANI–[Zn(8HQ)₂] composite, respectively. The aforementioned results suggest that the synthesized polymer composite is a potent material for electronic and optoelectronic applications such as light emitting diodes, solar cells and other semiconductor devices.