External energy transfer in amplified spontaneous emissions from MEH-PPV conjugated polymer

We observed amplified spontaneous emissions (ASEs) in solutions of conjugated polymer under high power neodymium-doped yttrium aluminum garnet (Nd:YAG) laser excitation. A solution of coumarin-485 dye (C485) and conjugated polymer (MEH-PPV) was prepared in tetrahydrofuran (THF). Here, C485 acted as a donor (with different ratios) while MEH-PPV served as an acceptor (with a constant ratio). Without the donor, MEH-PPV exhibited ASE only in the excimeric state; with the donor, however, it produced ASE in both the monomeric and excimeric states simultaneously. These results clearly show that it is possible to monitor and manipulate the excited state behavior of molecules by using an energy transfer process using laser-excited conjugated polymer.