Impact of hydrochloric acid doping on polyaniline conductivity and piezoelectric performance in polyaniline/bismuth oxyiodide nanocomposites

This study investigates the impact of hydrochloric acid (HCl) doping, ranging from 0.2 M to 1.25 M, on the conductivity of polyaniline (PANI) and the piezoelectric performance of polyaniline/bismuth oxyiodide (PANI/ BiOI) nanocomposites (NCs). Two distinct methods for fabricating NCs based on PANI and bismuth oxyiodide (BiOI) are proposed. Two distinct methods for fabricating PANI/BiOI NCs are proposed, and their optical and electrical properties are systematically examined. The direct allowed energy bandgap of the NCs is found to be approximately 1.9 eV. The piezoelectric performance, attributed to the 2D Janus structure of BiOI, is explored in detail, with the bulk piezoelectric coefficient measured at 1.43 (65) pm/V. Sensitivity to pressure interaction reached 21.1 (92) mV/bar, and the generated power was 5.09 nW for air pressure excitation in a composite consisting of 37.5 wt% BiOI and 62.5 wt% PANI doped with 0.2 M HCl, fabricated in-situ. The results demonstrate precise control over key parameters, including the fabrication method, sample thickness, HCl doping concentration, and BiOI content, highlighting the significant potential for enhancing nanogenerator functionality. These findings provide valuable insights into improving the performance of piezoelectric materials for energy harvesting technologies.