Organic photodetectors for use in medical sensors, blood oxygen recognition, and temperature measurement

In this work was carried out the electrical and optical characterization of sensitives in near infrared spectrum of PET/ITO/PEDOT:PSS/P3HT:PCBM/Al and PET/ITO/PEDOT:PSS/P3HT:PCBM/Ag/AgCl photodiodes for its application as blood oxygenation and temperature sensors, covering large areas and detecting wavelengths from 600–940 nm with an incident power of 25–30 mW under − 3 V reverse bias. The photodiodes exhibit responsivities around 10⁻³A/W, specific detectivity around 10⁶Hz^1/2/W and dark current around 10⁻⁴A. In blood oxygenation monitoring, the device exploits the differential absorption of blood at 600–700 nm (deoxygenated) and 940 nm (oxygenated), blocking light transmission within this range. The percentage of photoinduced current is derived from the characteristics I–V curves and the temperature measurement relies on changes in I–V curves and the disparity in total photoinduced current.