Single‐Step Selective Laser Writing of Flexible Photodetectors for Wearable Optoelectronics

Abstract

The increasing demand for wearable optoelectronics in biomedicine, prosthetics, and soft robotics calls for innovative and transformative technologies that permit facile fabrication of compact and flexible photodetectors with high performance. Herein, by developing a single‐step selective laser writing strategy that can finely tailor material properties through incident photon density control and lead to the formation of hierarchical hybrid nanocomposites, e.g., reduced graphene oxide (rGO)–zinc oxide (ZnO), a highly flexible and all rGO–ZnO hybrid‐based photodetector is successfully constructed. The device features 3D ultraporous hybrid films with high photoresponsivity as the active detection layer, and hybrid nanoflakes with superior electrical conductivity as interdigitated electrodes. Benefitting from enhanced photocarrier generation because of the ultraporous film morphology, efficient separation of electron–hole pairs at rGO–ZnO heterojunctions, and fast electron transport by highly conductive rGO nanosheets, the photodetector exhibits high, linear, and reproducible responsivities to a wide range of ultraviolet (UV) intensities. Furthermore, the excellent mechanical flexibility and robustness enable the photodetector to be conformally attached to skin, thus intimately monitoring the exposure dosage of human body to UV light for skin disease prevention. This study advances the fabrication of flexible optoelectronic devices with reduced complexity, facilitating the integration of wearable optoelectronics and epidermal systems.

Materials and Designs for Wearable Photodetectors

“…c,g) Mica substrate based PD using single‐step selective laser writing. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

“…Bendable mica substrate was combined with one‐step selective laser writing strategy for the fabrication of wearable PDs as shown in Figure c . The mixture of graphene oxide nanosheets and zinc acetate solution was coated on the mica substrate and femtosecond laser direct writing was conducted to reduce graphene oxide and synthesize ZnO, which served as the photoactive material.…”

Improved Photoresponse of UV Photodetectors by the Incorporation of Plasmonic Nanoparticles on GaN Through the Resonant Coupling of Localized Surface Plasmon Resonance

“…In recent years, ultraviolet (UV) detection has gained tremendous research attentions inspired by a wide range of applications in optoelectronics, environmental and biological monitoring, industrial automation, flame sensing, military communication, and space exploration [1][2][3][4][5][6][7][8][9][10]. The UV photodetectors feature the high sensitivity, fast response, low power consumption, and stable operation and thus can be utilized in the various aforementioned applications [11][12][13].…”

Low dimensional freestanding semiconductors for flexible optoelectronics: materials, synthesis, process, and applications

“…As another example, MoS 2 nanosheets have also been combined with graphene to create hybrid photodetectors as shown in [92,93]. In addition, a reduced graphene oxide (rGO) was used to realize UV photodetector with an excellent mechanical performance on a flexible substrate [94]. Other than employing rGO, TiO 2 particles or SWNTs have been employed to modify graphenebased photodetectors as shown in Figure 13(f).…”