Manley, P.; Abdi, F.F.; Berglund, S.; Islam, A. T. M. N.; Burger, S.; Krol, R.v.d.; Schmid, M.: Absorption Enhancement for Ultrathin Solar Fuel Devices with Plasmonic Gratings. ACS Applied Energy Materials 1 (2018), p. 5810-5815
Open Accesn Version

We present a concept for an ultrathin solar fuel device with a nanostructured back-contact. Using rigorous simulations, we show that the nanostructuring significantly increases the absorption in the semiconductor, CuBi2O4 in this case, by 47% (5.2 mA cm-2) through the excitation of plasmonic modes. We are able to attribute the resonances in the device to metal-insulator-metal plasmons coupled to either localized surface plasmon resonances or surface plasmon polaritons. Rounding applied to the metallic corners leads to a blue shift in the resonance wavelength while maintaining absorption enhancement, thus supporting the possibility for a successful realization of the device. For a 2D array, the tolerance of the polarization dependent absorption enhancement is investigated and compared to a planar structure. The device maintains an absorption enhancement up to incident angles of 75°. The study highlights the high potential for plasmonics in ultrathin optoelectronic devices such as in solar fuel generation.