ZnO-PEDOT: PSS nanocomposites as high-performance inorganic/organic hybrid UV photodetectors

<p>Three-dimensional (3D) ultraporous ZnO nanofilms have been the subject of intensive research as UV photodetectors driven by their large specific surface area, quantum confinement effect, and exceptional morphological connectivity. However, a poor interfacial connection between ZnO nanoparticles in these ultraporous nanostructures prevents the effective transfer of charge carriers across the interface, resulting in a drastic reduction in device sensitivity and electrical conductivity. To tackle this issue, we developed inorganic/organic hybrid nanocomposites made of highly porous ZnO nanofilms and poly (3,4-ethylenedioxythiophene)- polystyrene sulfonate (PEDOT: PSS) as highly robust, conductive UV photodetectors with fast response dynamics. A solid-state flame spray pyrolysis (FSP) method was employed to fabricate 3D ultraporous networks of ZnO nanoparticles on glass substrates having interdigitated electrodes with an average film porosity of >90%. The conductive PEDOT: PSS solution (with different polymer wt.%) was then drop-casted on the top of the ZnO nanostructure to fabricate the hybrid UV photodetectors. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and ultraviolet-visible (UV-Vis) spectroscopy were employed to study morphology, phase and crystal structure, chemical bonding and the optical performance of the fabricated structures. The optimised hybrid nanocomposite, with 0.025 wt.% polymer, featured a record-high UV photogenerated current of 617 μA under a low applied voltage of 1V and a wavelength of 375 nm. These results provide a high-performance hybrid for the low-cost production and implementation of UV photodetectors in complementary metal-oxide-semiconductor (CMOS) portable devices.</p>