In this work, we present flexible broadband photodetectors (PDs) fabricated by a deposition of nanostructured zinc oxide (ZnO) films on polyimide (PI) substrates by using cheap and scalable aqueous method Successive Ionic Layer Adsorption and Reaction (SILAR). In order to increase the long-wavelength absorption of the nanostructured ZnO layer, we created its intrinsic defects, including oxygen vacancies by post-treatment at 300 °C in vacuum and thus the light-sensitive material ZnO/PI was obtained. Then we applied silver nanoparticles (Ag NPs) from a silver sol onto a nanostructured ZnO film, which were visualized using SEM in the form of spheres up to 100 nm in size that increased the photocurrent and figures of merit of thus obtained light-sensitive material ZnO_Ag/PI due to localized surface plasmon resonance and double Schottky barriers at the Ag-ZnO interface. To fabricate photodetectors based on a photoconductive effect, these ZnO/PI and ZnO_Ag/PI materials were equipped with ohmic aluminum contacts. The spectral responsivity (Rλ up to 275 A/W to UV light) of solution-processed flexible broadband photodetector based on ZnO_Ag/PI material at different wavelengths of light and light power densities is better than Rλ of the ZnO/PI photodetector, and at least an order of magnitude higher than Rλ of photodetectors based on nanostructured zinc oxide described in recent articles. The external quantum efficiency (EQE) of both PDs in this study in UV–Vis-NIR spectra is very high in the range from 1∙102 to 9∙104 % and is better or of the same order of magnitude as the EQE data of modern flexible broadband high-sensitivity PDs based on nanostructured heterostructures containing ZnO. The specific detectivity in UV–Vis-NIR spectra is large for ZnO/PI (from 3.5∙1010 to 1∙1012 Jones) and especially for ZnO_Ag/PI (from 1.6∙1011 to 8.6∙1013 Jones), which indicates the ability of the PDs based on light-sensitive materials ZnO/PI and ZnO_Ag/PI to recognize a very weak light signal.
Zinc oxide nanostructured layer, Flexible broadband photodetector, Silver nanoparticle, External quantum efficiency, Specific detectivity
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N. P. Klochko, K. S. Klepikova, I. V. Khrypunova, V. R. Kopach, I. I. Tyukhov, S. I. Petrushenko, S. V. Dukarov, V. M. Sukhov, M. V. Kirichenko, and A. L. Khrypunova. "Solution-processed flexible broadband ZnO photodetector modified by Ag nanoparticles" Solar Energy (2021): 1-11. https://doi.org/10.1016/j.solener.2021.12.051