The photoluminescence(PL) properties of poly[ (2, 5 - diphenylene - 1, 3, 4 - oxadiazole) - 4, 4’ - viny-lene] (O - PPV) are investigated using absorption and excitation measurements for different concentration ratio...The photoluminescence(PL) properties of poly[ (2, 5 - diphenylene - 1, 3, 4 - oxadiazole) - 4, 4’ - viny-lene] (O - PPV) are investigated using absorption and excitation measurements for different concentration ratios of solid-state O - PPV/ PEO (polyethylene oxide ) blends, as well as by comparing PL spectra for dilute solution and solid state pristine O - PPV. The solid film of O - PPV/PEO is prepared to investigate the interaction between polymers. The O - PPV molecules are dispersed into PEO which is used as a inert material in order to change the interaction between O - PPV. In the O -PPV/PEO blends, it is found that the PL spectra excited by 300nm for different concentration ratios are different. There are three peaks in the PL spectra of 1: 100 and 1: 200 (O - PPV/PEO) blends, and the relative intensities of peaks at 500nm and 460nm gradually decrease with lowering the concentrations of O - PPV. There leaves one peak at 416nm when the ratio of O - PPV to PEO is below 1: 300, and PL shape does not change any longer. The results show that the solid-state O - PPV emission arises from interchain charge-transfer states due to interchain effects.According to the absorption and photoluminescence spectra of the solid films, it is also believed that there are types of localized and delocalized states in conjugated polymers. The two types of states have different effects on charge-transfer state in different concentrations of solid films.展开更多
文摘The photoluminescence(PL) properties of poly[ (2, 5 - diphenylene - 1, 3, 4 - oxadiazole) - 4, 4’ - viny-lene] (O - PPV) are investigated using absorption and excitation measurements for different concentration ratios of solid-state O - PPV/ PEO (polyethylene oxide ) blends, as well as by comparing PL spectra for dilute solution and solid state pristine O - PPV. The solid film of O - PPV/PEO is prepared to investigate the interaction between polymers. The O - PPV molecules are dispersed into PEO which is used as a inert material in order to change the interaction between O - PPV. In the O -PPV/PEO blends, it is found that the PL spectra excited by 300nm for different concentration ratios are different. There are three peaks in the PL spectra of 1: 100 and 1: 200 (O - PPV/PEO) blends, and the relative intensities of peaks at 500nm and 460nm gradually decrease with lowering the concentrations of O - PPV. There leaves one peak at 416nm when the ratio of O - PPV to PEO is below 1: 300, and PL shape does not change any longer. The results show that the solid-state O - PPV emission arises from interchain charge-transfer states due to interchain effects.According to the absorption and photoluminescence spectra of the solid films, it is also believed that there are types of localized and delocalized states in conjugated polymers. The two types of states have different effects on charge-transfer state in different concentrations of solid films.
