Photoluminescence enhancement of tris(8-hydroxyquinolinato)aluminum thin film by plasmonic Ag nanotriangle array fabricated by nanosphere lithography

Enhancement of 4.4-fold photoluminescence (PL) of tris(8-hydroxyquinolinato)aluminum (Alq3) thin film was observed in the presence of 50-nm thick Ag nanotriangles (NTs) compared with bare Alq3 film at room temperature. According to the temperature dependence of integrated PL intensity and the PL lifetime obtained from time-resolved PL measurements, an increase in radiative recombination rate was observed over a wide temperature range. Because the absorption peak originated from localized surface plasmon (LSP) states and the emission spectra are well overlapped, the observed enhancement can be explained by efficient coupling of the LSP of the Ag NTs with the emission from the Alq3.