Spirulina-Based Self-Powered Biological UV Photodetectors

Abstract

Overexposure to ultraviolet (UV) radiation can be monitored by a portable UV photodetector that provides reminders to humans. However, the traditional UV photodetector falls short of practical demands due to the power supply problem, impeding further development. This study describes an exceptionally sensitive self-powered biological ultraviolet photodetector leveraging a photosynthetic organism sandwiched between two electrodes. By the introduction of a cyanobacteria Spirulina sp. as a photoactive material, the device achieves exceptional sensitivity and stability in UV light detection under self-powered operation. Notably, upon illumination with 372 nm at zero bias, the device demonstrates impressive responsivity and detectivity values of 65 mA/W and 9 × 10¹⁰ Jones for the intensity of 0.4 mW/cm², respectively. Additionally, the optimized device showed rapid rise and decay times, clocking in approximately 0.078 and 0.20 s, respectively, even at low intensity. There are many inorganic self-powered UV photodetectors widely used, but biological materials are underexplored. Now, here, we fabricated the device with nontoxic, renewable live cyanobacterial cells to mitigate environmental harm. In summary, the self-powered Spirulina-based UV photodetector demonstrates exceptional sensitivity, stability, and quick response and recovery times, making it a promising and environmentally friendly solution to the current challenges in UV detection applications.