Dresden 2017 – wissenschaftliches Programm
CPP 33.1: Vortrag
Mittwoch, 22. März 2017, 09:30–09:45, POT 81
Controlling Tamm-plasmons for organic narrowband NIR photodetectors based on intermolecular charge transfer — •Andreas Mischok, Bernhard Siegmund, Dhriti Ghosh, Johannes Benduhn, Donato Spoltore, Hartmut Fröb, Christian Körner, Koen Vandewal, and Karl Leo — Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Dresden
Combining a periodic distributed Bragg reflector (DBR) with a thin metal film leads to the formation of Tamm-plasmon-polaritons (TP) as sharp resonances at the DBR-metal interface. Here, we utilize such TP states to realize cavity-enhanced near infrared photodetection using an organic donor-acceptor bulk heterojunction. In such blend films, intermolecular charge transfer states play an important role during the separation of excitons. Furthermore, they can also be directly optically excited, albeit exhibiting only weak absorption coefficients and a broad linewidth. The weak extinction typically makes these states uninteresting for direct photocurrent generation, however they provide an ideal base for cavity-enhanced devices. Controlling the formation of TP resonances in a DBR-solar cell stack, we create a high-Q microcavity in the near-infrared, targeting the CT state energy. These tunable Tamm-plasmon-charge-transfer (TPCT) resonances enable direct photodetection of light well below the bandgap of the organic absorbers at zero bias and facilitate detector external quantum efficiencies of 17 % as well as a linewidth below 25 nm for spectroscopic applications.