Flexible Photodetectors: Flexible Light‐to‐Frequency Conversion Circuits Built with Si‐Based Frequency‐to‐Digital Converters via Complementary Photosensitive Ring Oscillators with p‐Type SWNT and n‐Type a‐IGZO Thin Film Transistors (Small 26/2021)

As a system-level photodetector, flexible light-to-frequency conversion circuits (LFCs) are implemented using a-IGZO and SWNT thin-film transistors. Combined with LFC, CMOS-based frequency-to-digital converter is integrated for digitization of analog signal from LFCs. With the better noise immunity on LFCs, the proposed system by Junyoung Song, Sung Hun Jin, and co-workers (article number 2008131) will significantly contribute to the newly conceived Internet-of-Things (IoT) or smart flexible sensor systems.