An In-Memory Personal Dosimeter based on Ultraviolet Radiation-Programmed Nonvolatile Memory

The monitoring of ultraviolet (UV) radiation, especially UVC and UVB, is critical for personal health and occupational health and safety monitoring. However, existing UV dosimetry technologies face challenges in balancing cost, portability, accuracy, and power efficiency. To address these challenges, we develop a UV-programmed non-volatile memory device based on polyvinylpyrrolidone (PVP)-functionalized carbon nanotube (CNT) network films. This memory device functions as a dosimeter utilizing UV-induced bond scission in PVP and the subsequent chemisorption of the resulting radicals to modulate CNT network conductance, exhibiting precise cumulative UV dose tracking ability with a high resolution of 36 μJ/cm². The cumulative UVC dose can be directly read using a low-cost circuit based on the linear relationship between conductance and UV dose. With a high dynamic range of 90 mJ/cm², the device is sufficient for monitoring typical UV exposure within a few days, ensuring practical usability. Additionally, it demonstrates excellent reproducibility, stability under mechanical deformation, and a scalable, solution-processable fabrication process at a cost of ~1 cent per unit. By integrating sensing and memory functionality into a disposable, ultra-low-cost platform, this personal UV dosimeter offers an accessible solution for health and occupational safety monitoring in resource-limited areas as frugal innovation.