Highly crystalline hexagonal PbI₂ sheets on polyaniline/antimony tin oxide surface as a novel and highly efficient photodetector in UV, Vis, and near IR regions

The work reports on the preparation of polyaniline/lead iodide optoelectronic photodetector on antimony tin oxide (ATO) glass (PANI/PbI₂/ATO) for providing a low-cost light sensor in the UV, Vis, and near IR regions (wide optical range photodetector). The deposition of PbI₂ nanoparticles was carried out on the surface of PANI using the ionic adsorption deposition method. Four ATO/PANI/PbI₂ composites (I, II, III, and IV) were produced by varying the Pb²⁺ concentrations (0.01, 0.03, 0.05, and 0.07 M, respectively). The chemical structure, morphology, optical, and electrical properties were assessed using different analytical tools. Scanning electron microscopy (SEM) imaging revealed the formation of a nanoporous PANI network. After PbI₂ incorporation within the PANI network, white nanoparticles formed on the surface. The average size of the PbI₂ nanoparticles was 220, 270, 280, and 320 nm for Pb²⁺ concentration of 0.01, 0.03, 0.05, and 0.07 M, respectively. Moreover, x-ray diffraction analysis confirmed PANI/PbI₂ composite formation, as witnessed by the appearance of new peaks at 12.77°, 34.31°, and 38.8 ° characteristic of PbI₂. Through the optical analyses, the band gap values of the PANI/PbI₂ composites I, II, III, and IV were 2.63, 2.51, 2.46, and 2.48 eV, respectively. ATO/composite III was applied as an optoelectronic device for detection the light under different intensities or wavelengths, in which the current density (J_ph) increase from 2.5 to 3.42 mA cm⁻² upon increasing of the light intensity from 25 to 100 mW.cm⁻², respectively. Moreover, the J_ph recorded an optimum value of 3.33 mA cm⁻² at 390 nm, which decreased to 2.09 mA cm⁻² at 490 nm and increased again to 3.13 mA cm⁻² at 636 nm. The optoelectronic photodetector exhibited an optimum incident photon to electron conversion efficiency (IPCE) of 10.7% at 390 nm. The photoresponsivity (R) and detectivity (D) were determined to be 107 mA cm⁻² and 3.38 × 10¹⁰ Jones, respectively. Finally, a simple mechanism was proposed to account for the response of the prepared optoelectronic devices to the photon flux. Soon, our team will work on design an optoelectronic device that can be applied in the industrial field through the high technology device such as cameras and aircrafts for light detection.