An Ultrafast Organic Photodetector with Low Dark Current for Optical Communication Systems

Photodetectors are widely applied in imaging, communication, medical detection, and many other fields. Organic photodetectors (OPDs) have attracted extensive attention due to their inherent mechanical flexibility, low cost, good light absorption, and ease of processing. However, the low response speed of OPDs has always been a major problem, which hinders their application in the field of fast optical communication. In addition, fabricating high-speed OPDs again has the problems of large dark current and complex structure. Here, a high-speed OPD based on a simple planar heterojunction with a bandwidth of 107 MHz is achieved. More significantly, the dark current of the device is effectively suppressed by electrode injection control. Moreover, this nanosecond OPD is successfully applied to optical communication with a transmission rate up to 40 Mbit/s.