Enhancement in photodetection properties of PbI₂ with graphene oxide doping for visible-light photodetectors

Herein, lead iodide (PbI₂) nanorods/graphene oxide (GO) nanocomposites have been successfully achieved at low temperature via microwave-assisted syntheses route. The X-ray diffraction (XRD) analysis confirm good crystallinity and absence of any impurity in the prepared hybrid nanostructures which further confirmed through Raman analysis. The XRD and Raman study also confirm the doping of GO in 2H polytypic PbI₂ structure. The average crystallite size of PbI₂ is calculated to be 20 nm which found to be increased to 53 nm in the case of GO-PbI₂ for high intensity peak. Scanning electron microscope (SEM) images reveal that the GO sheets are decorated with PbI₂ nanoparticles and nanorods. The absorption spectra of PbI₂ was found to broaden whereas energy bandgap of GO-PbI₂ decreases to 2.83 eV in compare to 3.24 eV for PbI₂. The effect of graphene oxide doping on photodetector performance of PbI₂ was elucidated by measuring the I-V characteristics under 532 nm laser light illumination. The pure PbI₂ exhibits a stable and reversible photodetector performance with responsivity of 0.060 AW⁻¹, detectivity of 6.38 × 10¹⁰ Jones, EQE of ∼14 % and response time of 224 ms. For GO-doped PbI₂, these parameters were found to be improved to 0.182 AW⁻¹, 1.79 × 10¹¹ Jones, ∼42 %, and 128 ms, respectively.