We have investigated the optical properties of a synthesized polymer containing perylene tetracarboxylic diimide (PDI) in different solvents. The structured absorption and photoluminescence (PL) spectra of the PDI in the polymer are sensitive to the solvents. The excited states with the PL peaks at 530 and 570 nm have the same PL excitation bands and life times, but the PL excitation band of the 625 nm excited states with long life time is different from the others. The PL bands with the peaks at 530 and 570 nm originate from the separated PDIs, whereas the 625 nm emission band is connected with the π–π stacked aggregates of the PDI in the polymer. The polymer chains become coiled to be favor of forming the π–π stacked aggregates of the PDI in weak polar solvent. The experimental results indicate that more π–π stacked aggregates are formed in tetrahydrofuran/ethanol blend solvents due to the collapsed polymer chains, but the PL intensity of the aggregates is precipitately decreased with the increase in the content of ethanol due to concentration quenching. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4113–4118, 2013

We have investigated the optical properties of poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] containing oxadiazole in backbone (MEH-OPPV) in dilute tetrahydrofuran solution and solid solution films. There is a large dihedral angle between the two adjacent monomer units in MEH-OPPV, which restrains interchain interactions and destroys the conjugation of the polymer to result in blue shifted absorption and emission spectra. The red shifted photoluminescence (PL) peak is continuously changed in the solid solution films with increasing the concentration of MEH-OPPV. Comparison with the dilute solution, an obvious shoulder peak at 465 nm is found in the UV–vis absorption and PL excitation (PLE) spectra of the MEH-OPPV film. The intensity of the PLE shoulder at 465 nm is increased with the concentration of MEH-OPPV in the solid solution films, which is connected with the aggregation of the MEH-OPPV chains. The interchain interactions are restrained and the π-stack aggregates of the polymer chains can not form in the MEH-OPPV due to the large dihedral angle, and then the interchain species are effectively suppressed in the MEH-OPPV films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A series of composite polymer nanoparticles was prepared from poly(N-vinylcarbazole) (PVK) and poly(2,5-bistriethoxy-p-phenylene vinylene-alt-phenylene vinylene) (BTEO–PPV-alt-PPV). The nanoparticle sizes were measured to be in the range of 50–80 nm with transmission electron microscopy. The photoluminescence intensity of PVK decreased with the content of BTEO–PPV-alt-PPV increasing in the composite polymer nanoparticles because the excited states in PVK were quenched by BTEO–PPV-alt-PPV. The emission from BTEO–PPV-alt-PPV was enhanced in the composite polymer nanoparticles because of energy transfer from PVK to BTEO–PPV-alt-PPV for excitation at the absorption maximum of PVK. The energy-transfer efficiency was markedly improved in the composite polymer nanoparticles versus the composite polymer films according to emission spectral analyses. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

In this study, we present the optical properties of the poly(N-vinylcarbazole) (PVK) films doped with tris(8-hydroxyquinoline) aluminum (Alq₃). It has been found that the photoluminescence (PL) spectrum of the PVK film overlaps well with the absorption band of Alq₃. When excited at the absorption maximum of PVK, the doped PVK films show enhanced emissions from the Alq₃ component. The PL enhancement is considered to be due to energy transfer from PVK to Alq₃ in the doped PVK films by analyzing the PL, PL excitation, and time-resolved fluorescence spectra. The energy transfer efficiency is increased with increasing the concentration of Alq₃ in the doped PVK film according to time-resolved fluorescence spectra. The energy transfer process has been discussed according to the Förster mechanism. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1772–1777, 2009