Luminescence quenching of ordered π-conjugated molecules near a metal surface: Quaterthiophene and PTCDA on Ag(111)

摘要: Photoluminescence (PL) spectra were measured for highly ordered films of two planar \ensuremath{\pi}-conjugated molecules [quaterthiophene and 3,4,9,10-perylenetetracarboxylicacid-dianhydride (PTCDA)], which both grown on a Ag(111) surface with thicknesses varied between 1 30 monolayers. For the PL is quenched below detection limit two-layer-thick increases very steeply thicker films. These results cannot be explained within classical image dipole theory, but demonstrate presence ultrafast, nonradiative short-range decay processes, such as charge delocalization tunneling. It effective first chemisorbed molecular layer second top first. Implications these findings luminescence experiments organic in close contact to metal surfaces are discussed.