High-Performance Flexible Ultraviolet Photodetectors Based on AZO/ZnO/PVK/PEDOT:PSS Heterostructures Integrated on Human Hair

Abstract

Flexible optoelectronics is an emerging research field that has attracted a great deal of interest in recent years due to the special functions and potential applications of these devices in flexible image sensors, optical computing, energy conversion devices, the Internet of Things, and other technologies. Here, we examine the high-performance ultraviolet (UV) photodetectors using AZO/ZnO nanorods/PVK/PEDOT:PSS heterostructures integrated on human hair. Due to the precise interfacial energy-level alignment among all layers and superior mechanical characteristics of human hair, the as-obtained photodetector shows a fast response time, high photoresponsivity, and excellent flexibility. According to integrate 7 heterostructures as 7 display pixels, the flexible UV-image sensor has superior device performance and outstanding flexibility and can produce vivid and accurate images of Arabic numerals from 0 to 9. Different combinations of the two heterostructures can also be used to achieve flexible photon-triggered logic functions, including AND, OR, and NAND gates. Our findings indicate the possibility of using human hair as a fiber-shaped flexible substrate and will allow the use of hair-based hierarchical heterostructures as building blocks to create exciting opportunities for next-generation high-performance, multifunctional, low-cost, and flexible optoelectronic devices.

Recent Progress of Heterojunction Ultraviolet Photodetectors: Materials, Integrations, and Applications

“…The hybrid PDs based on p‐type organic molecules with tunable functionality and n‐type inorganic semiconductors with superior intrinsic carrier mobility, usually present high photodetecting performance, thanks to the efficient separation and transfer of photoinduced charge carriers resulting from the p‐n heterojunctions. Various kinds of organic materials, such as polyaniline (PANI),90 poly(vinyl alcohol) (PVA),91 poly(arcylonitrile) (PAN),27 poly(vinyl carbazole) (PVK),92 polypyrrole (PPy),93 and even pyrene‐tricyanofuran derivatives,94,95 are also adopted to modify the photoelectric properties of semiconductor‐based PDs 96…”

“…Due to the small volume of a fiber, it seems easier for fiber PDs to achieve large‐scale integration. Human hair can act as the core for supporting a fiber PD 96. As seen from Figure a, simple sputtering and hydrothermal strategies are in turn applied to form the Al‐doped ZnO/ZnO nanorods layer on a hair substrate.…”

“…a) Schematic diagram, photocurrent before and after bending, and applications of Al:ZnO/ZnO/PVK/PEDOT:PSS PD. Reproduced with permission 96. Copyright 2019, American Chemical Society.…”

High‐Performance Ultraviolet‐Visible Light‐Sensitive 2D‐MoS2/1D‐ZnO Heterostructure Photodetectors

“…The enlarged portions of one test cycle are presented in Figure c and d to estimate the photoresponse speed. The rise time (t rise , defined as time required to increase the peak photocurrent from 10 % to 90 %) is found to be 0.9 s and 0.14 s under 365 nm and 532 nm light irradiation, respectively . The decay time (t decay , defined as time required to drop the peak photocurrent from 90 % to 10 %) is around 1.04 s and 8.32 s under 365 nm and 532 nm light irradiation, respectively.…”

Self‐Powered Flexible TiO2 Fibrous Photodetectors: Heterojunction with P3HT and Boosted Responsivity and Selectivity by Au Nanoparticles

“…Inorganic‐organic hybrid heterojunctions afford a promising way by combining the excellent intrinsic carrier mobility of inorganic materials and the abundant merits of organic components with tunable functionality, easy of fabrication, low cost and high flexibility. [ 23,24,32–35 ] P3HT is a typical π‐electron conjugated polymer with a high hole‐transport rate and strong visible light absorption, which has been widely applied in photovoltaic devices owing to the semiconductivity and high stability. [ 32,33,36 ] Among the inorganic semiconductors, anodic TiO 2 nanotubes (TiO 2 NTs) array standing vertically on the surface of Ti metal is a promising candidate to construct high‐performance self‐powered PDs in the viewpoint of high surface‐to‐volume ratio, well‐defined charge transfer pathway and good adhesion to Ti metal substrate, leading to good photosensitivity, high responsivity and excellent stability.…”