Experimental and computational investigation of CH3NH3PbI3 material for next-generation fiber optic applications

A CH 3 NH 3 PbI 3 film was fabricated using a two-step spin-coating technique, following the successful synthesis of methylammonium iodide. X-ray Diffraction analysis confirmed the film's high crystallinity, with prominent peaks at 14.04° and 28.29° corresponding to the (110) and (220) planes, respectively. It exhibits sharp peaks, indicating the absence of impurities, and has an average crystallite size of 40 nm, calculated using the Scherrer equation. Optical and morphological characterization revealed a direct band gap of 1.66 eV, strong visible-light absorption, and a dense, crystalline morphology. Computational studies further highlighted the material's potential for fiber optic applications. The optical behavior of CH 3 NH 3 PbI 3 is marked by a pronounced light–matter interaction in the visible region. Its refractive index reaches a maximum around 3 eV, while the absorption coefficient attains its highest value near 10 eV. The material reflects strongly below 5 eV but becomes increasingly transparent at higher photon energies. The dielectric function reveals energy storage at low energies and significant energy dissipation, with a peaking near 4 eV. Together, these optical characteristics and the pronounced variation in refractive index point to the potential for nonlinear optical effects. Highly crystalline CH 3 NH 3 PbI 3 film prepared by spin-coating exhibits a direct band gap of 1.66 eV with strong light absorption. Experimental and computational studies validate their suitability for fiber optic applications. • CH 3 NH 3 PbI 3 films fabricated by spin coating are highly crystalline, pure, and show a direct band gap with strong visible light absorption. • Their optical properties, including a high refractive index at 3 eV, strong absorption near 10 eV, and efficient energy storage and dissipation, highlight their potential for fiber optic and nonlinear photonic applications.