Near (NIR) to shortwave (SWIR) infrared optical imaging, in particular, is used to assess the oxygen arterial saturation by quantifying the ratio of oxyhemoglobin to deoxyhemoglobin. The benefit of reduced tissue absorption in this spectral range (biological window: 700-1400 nm) [4] enables non-invasive direct probing. [1,5] First, flexible but flat detector concepts reveal the potential of an improved adaption to the skin and are based on organic [6] or hybrid graphene-colloidal PbS quantum dots (QDs) [7] materials. E-textiles based on smart fibers further improve interfacing the skin by reducing the structure dimension (from 2D flat substrate to 1D fibers) [8] and demonstrate their potential for energy harvesting and storage, light emission, as well as sensing applications. [9][10][11][12][13][14] Optimally, an e-textile allows for the integration of a diverse set of functionalities to, for instance, assess different vital signs as predictors of the overall health status of an individual. This requires the integration of multiple functions to a single fiber and poses a distinct need for new technological approaches. Methods to integrate IR detectors locally and on curved surfaces are, thus, highly desired. The combination of low-dimensional nanomaterials, such as Hybrid graphene-colloidal PbS quantum dots (QDs) phototransistors are promising to overcome the geometrical restrictions of photodetectors to flat substrates. While compatible with conformal manufacturing, the experimental demonstration of their application to curved surfaces remains elusive. This work demonstrates the seamless integration of an infrared (IR) photodetector to a polymer optical fiber (POF) by wrapping graphene around the POF of 1 mm in diameter and, subsequently, inkjet printing of PbS QDs onto the curved surface. The device acts as a functional coating and detects infrared light propagating through the POF without interrupting the waveguide. The formulated α-terpineol and hexane co-solvent ink supports drop-on-demand placement with a resolution of 50 µm and is colloidally stable over 7 months. A responsivity map over gate voltage and temperature (300 to 80 K) of a device, fabricated on a common flat substrate, reveals a responsivity of R ≈ 1 × 10 3 AW −1 (irradiance ≈1 µW cm −2 ) and a detectivity of D* ≈ 1 × 10 10 Jones at 1.6 µm wavelength. This work brings the integration of this cost-effective and adaptable hybrid detector approach closer to multifunctional e-textiles and will, notably, help to improve the interfacing of the skin as desired for wearable and non-invasive healthcare applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.