Nanospherical arsenic(iii) oxoiodide/iodide-intercalated poly( <i>N</i> -methylpyrrole) composite synthesis for broad-spectrum optical detection

Abstract This study presents the successful synthesis of an innovative nanospherical As( iii ) oxoiodide/iodide-intercalated poly( N -methylpyrrole) composite (As( iii )OI/I-PNMP NS composite), which serves as an n-type active layer in a high-performance photodetector. The composite is coated onto a polypyrrole (PPy) base, creating a novel As( iii )OI/I-PNMP/PPy heterojunction device that efficiently senses photons. Structural analysis of the synthesized composite shows uniformly distributed spherical nanoparticles, averaging around 100 nm in diameter, on a rough, highly textured surface that improves light–matter interaction. It exhibits a promising crystallite size of 21 nm and an optimal bandgap of 2.35 eV, facilitating effective absorption across a broad spectral range. The optoelectronic performance of the photodetector was systematically tested under varying illumination conditions, employing photons from both UV and visible (Vis) regions. During illumination, the photoresponse was analyzed using current density measurements ( J ph ), highlighting the composite’s essential role in charge carrier generation and transport. The device’s photoresponsivity ( R ) was notably improved, achieving values between 0.23 and 0.28 mA/W, reflecting the material’s high sensitivity to incoming light. Furthermore, the detectivity ( D ), an important performance metric for photodetectors, was calculated to be between 0.52 × 10 8 and 0.63 × 10 8 Jones, indicating excellent proficiency in detecting low-intensity optical signals. In summary, incorporating As( iii )OI with I-doped PNMP into a PPy-based structure signifies a promising strategy for developing broadband, high-efficiency photodetectors, with significant potential for future use in optoelectronic sensing and imaging technologies.