Flexible copper iodide photodetector with Schottky contacts and surface plasmon resonance effect induced by silver nanoparticles

In this work, a low-cost aqueous automatic Successive Ionic Layer Adsorption and Reaction (SILAR) method used to deposit a nanostructured sulfur-doped copper iodide (CuI) film with a single-phase γ-CuI nanoflake structure on a polyethylene terephthalate (PET) substrate. The idea of one-step vacuum evaporation of silver was implemented to simultaneously obtain two back-to-back connected Schottky contacts CuI/Ag and hemispherical silver nanoparticles (AgNPs) with a diameter of ∼40 nm, capable of creating the effect of localized surface plasmon resonance (LSPR) with the fabrication of a flexible CuI@Ag/PET UV–Vis photodetector. Its photoelectric parameters show a linear dynamic range value of more than 19 dB, responsivity of 27 mA/W, specific detectivity of 5.3‧10¹⁰ Jones and external quantum efficiency of 9.1 %. Under UV, blue, green and red light illumination and bias voltage from 20 mV to 2 V, the CuI@Ag/PET UV–Vis photodetector exhibits excellent flexibility and high stability of characteristics even after 500 bending cycles.