Multiple Narrowband Bidirectional Self-Powered Organic Photodetector with Fast Response

Benefiting from the discovery of novel organic semiconductor materials bearing tunable absorption characteristics, narrowband organic photodetectors (OPDs) with improved performance are reported. Alongside new photoactive materials synthesis, several device engineering strategies are introduced to achieve narrowband OPDs, allowing less dependence of the device performance on the synthetic variation control, such as batch-to-batch differences in molecular weight. However, fabrication of multiband OPDs remains a challenge. Current solutions are usually based on vertical multi-stacking of photosensitive layers with different absorption spectra and voltage-modulated charge collection/injection, which renders the device fabrication too complex, while their response speed and band selectivity is limited. In this work, the concept of optical cavity is adopted to demonstrate self-powered and fast response speed single-junction bidirectional organic photodetectors with dual narrowband detection in the ultraviolet (UV) and visible part of the spectrum. Application of these devices in encrypted UV communication is successfully demonstrated. A third band in the near infrared (NIR) is possible to be isolated, rendering these high-performing and simple to manufacture multiband OPD devices attractive for high-resolution imaging and optical wireless communication.