ハイパボリック・メタマテリアルによる有機半導体薄膜の蛍光増強

抄録

We have experimentally investigated photoluminescence from thin film of organic semiconductor deposited on hyperbolic metamaterials (HMMs). The HMMs composed of alternating multilayer of subwavelength-thick silver and titanium dioxide with various fill fractions were fabricated utilizing magnetron sputtering. Their optical properties were evaluated from transmittance and reflectance spectra and also compared with theoretical effective dielectric characteristics obtained by effective medium theory. Thin film of organic semiconductor, Tris-(8-hydroxyquinoline)aluminum, Alq3, was deposited by thermal evaporation on the fabricated HMMs. The samples were excited using ultraviolet light emitting diode (UV-LED) and photoluminescence (PL) spectra were measured using multichannel spectrometer. A 2.6-fold enhancement of PL was achieved from Alq3 on the optimized HMM using as a substrate. Our findings may be utilized to develop various types of efficient optical devices based on organic semiconductors such as organic light emitting diodes (OLEDs) and organic solid state lasers.