Localized Surface-Plasmon Enhanced Near-Infrared Organic Photodetector

摘要

Near infrared (NIR) organic photodetector (OPD) has exhibited tremendous potential in research due to mechanical flexibility, optoelectronic tunability, and low cost. However, the limited NIR light absorption, low carrier mobility, and relatively low photon-to-electron conversion efficiency in organic photoactive layer have restricted further development of OPD. To address these challenges, localized surface-plasmon resonance (LSPR) enhanced D18:Y6 OPD is systematically designed and fabricated with uniform Ag nanocubes (AgNCs) of 60 nm deposited right on D18:Y6 organic photoactive layers, realizing a 25-fold enhancement in responsivity and detectivity which reach 2200 mA W~(?1) and 2.8 × 10~(12) Jones, respectively, upon 850 nm laser excitation compared with pristine device without AgNCs. The detailed COMSOL Physics simulation of as-obtained devices with AgNCs indicates that electric filed is strongly amplified and concentrated within the D18:Y6 film. The enhancement of photoluminescence intensity in D18:Y6 films with AgNCs further verifies the resonant enhancement of light absorption in the D18:Y6 film embedded with AgNCs. To get in-depth knowledge of the LSPR enhancement effect on OPD, the photocurrent enhancement of devices with different laser power densities and plasmonic modes have been systematically explored. Therefore, this work has opened a new window to enhance the photoresponse for next generation NIR OPDs.