Proceedings of International online conference on Hybrid materials and optoelectronic devices (HYBRIDOE)
DOI: https://doi.org/10.29363/nanoge.hybridoe.2020.016
Publication date: 4th December 2020
The solution-processable dual-mode organic photodetectors (OPDs) comprise a tri-layer configuration of visible light absorber/optical spacer/near-infrared (NIR) light absorber. In the presence of NIR light, photocurrent is produced in the NIR light absorbing layer, due to the trap-assisted charge injection at the organic/cathode interface at a reverse bias. In the presence of visible light, photocurrent is produced in the visible light absorbing layer, enabled by the trap-assisted charge injection at the anode/organic interface at a forward bias, as shown in TOC. A high responsivity of >10 A/W is obtained in both short and long wavelengths. The dual-mode OPDs exhibit an NIR light response operated at a reverse bias and a visible light response operated at a forward bias, with a high specific detectivity of ~1013 Jones in both NIR and visible light ranges.[1,2]
The NIR and visible light dual-mode OPDs are an attractive alternative optical detecting technology to the conventional single-mode photodetectors. The solution-processable fabrication processes also lead to significant cost benefits, thereby creating next-generation large-area and flexible OPDs. The unique dual-mode light response properties discussed in this talk offer an attractive option for new photodetector concept. The dual-mode OPDs offer additional advantages such as having a bias-switchable spectral response for applications in environmental pollution detection, health and security monitoring in two distinct bands.
This work was financially supported by the Research Grants Council of Hong Kong Special Administrative Region, China, General Research Fund (12302817, 12303920), NSFC/RGC Joint Research Scheme (N_HKBU201/19).