Relaxation dynamics of photoexcitations in polydiacetylene films

The relaxation dynamics of photoexcitations in a polydiacetylene (poly-3BCMU) film was investigated by femtosecond time-resolved absorption spectroscopy. Spectral change due to several nonlinear optical processes, i.e. hole burning, Raman gain, and dynamic Stark effect, was observed. The difference absorption spectra of singlet and triplet excitons minus ground state were measured. The photoexcited singlet excitons relaxed to the self-trapped state with the time constant of 150+or-50 fs. The lifetime of the self-trapped excitons was 2.0+or-0.1 ps at 10 K and 1.5+or-0.2 ps at 290 K. The lifetime of the triplet excitons was much longer than several tens of picoseconds and was consistent with the lifetime of 18 mu s obtained by nanosecond spectroscopy. >

[1]  Antonetti,et al.  "Dressed excitons" in a multiple-quantum-well structure: Evidence for an optical Stark effect with femtosecond response time. , 1986, Physical review letters.

[2]  T. Kotaka,et al.  Urethane-substituted poly(diacetylene): electrical conductivity of poly[5,7-dodecadiyne-1,12-diol bis([(n-butoxycarbonyl)methyl]urethane)] in amorphous and single-crystalline forms , 1984 .

[3]  Dynamics of photogenerated solitons in trans-polyacetylene , 1988 .

[4]  G. M. Carter,et al.  Nonlinear optical processes in a polydiacetylene measured with femtosecond duration laser pulses , 1986 .

[6]  H. Sixl,et al.  Excitons and Polarons in Polyconjugated Diacetylene Molecules , 1985 .

[7]  V. A. Khodovoi,et al.  Reviews of Topical Problems: Current Methods for the Study of the Stark Effect in Atoms , 1968 .

[8]  A. Vonlanthen,et al.  Single crystal 2,4-hexadiynylene-bis (p-toluenesulfonate): Elastic properties and phase transitions in the monomer and polymer , 1983 .

[9]  Takayoshi Kobayashi,et al.  Nanosecond time-resolved photoinduced absorption of trans-polyacetylene , 1987 .

[10]  Greene,et al.  Phonon-mediated optical nonlinearity in polydiacetylene. , 1988, Physical review letters.

[11]  K. Nasu.  Tunneling and relaxation from the free state to the self-localized state of the exciton: Nondiabatic multi-step theory , 1987 .

[12]  M. Taiji,et al.  Femtosecond to Microsecond Dynamics of Photoexcitations in a Polydiacetylene Film , 1988 .

[13]  S. Suhai.  Green's-function study of optical properties of polymers: Charge-transfer exciton spectra of polydiacetylenes , 1984 .

[14]  Ronald R. Chance,et al.  A planar–nonplanar conformational transition in conjugated polymer solutions , 1979 .

[15]  Takayoshi Kobayashi,et al.  Nanosecond time-resolved reflection spectrum of a polydiacetylene single crystal , 1984 .

[16]  Fröhlich,et al.  Observation of the resonant optical Stark effect in a semiconductor. , 1985, Physical review letters.

[17]  J. Gordon,et al.  Negative dispersion using pairs of prisms. , 1984, Optics letters.

[18]  J. Schrieffer,et al.  Soliton dynamics in polyacetylene. , 1980, Proceedings of the National Academy of Sciences of the United States of America.

[19]  A. Bishop.  Defect states in polyacetylene and polydiacetylene , 1980 .

[20]  Takayoshi Kobayashi,et al.  Fluorescence spectrum and lifetime of urethane-substituted polydiacetylene in solution , 1985 .

[21]  Takayoshi Kobayashi,et al.  Dependence of the spectrum and decay of transient photoinduced reflectance change on excitation wavelength and intensity in polydiacetylene single crystals , 1987 .

[22]  Sokoloff,et al.  Transient oscillations in the vicinity of excitons and in the band of semiconductors. , 1988, Physical review. B, Condensed matter.

[23]  Takayoshi Kobayashi,et al.  Femtosecond Spectroscopy of Poly(3-Methylthiophene) Films , 1990 .

[24]  Toshiaki Hattori,et al.  Femtosecond dephasing in a polydiacetylene film measured by degenerate four-wave mixing with an incoherent nanosecond laser , 1987 .

[25]  E. Hanamura,et al.  Electronic structure and photo-induced structure change of polydiacetylene crystal , 1987 .

[26]  J. Gordon,et al.  Dynamics of spectral hole burning , 1988 .

[27]  K. Wong,et al.  Luminescence of a Fully Polymerized Polydiacetylene , 1985 .

[28]  Robert R. Alfano,et al.  Ultrafast resonant optical Kerr effect in 4-butoxycarbonylmethylurethane polydiacetylene , 1987 .

[29]  Alan J. Heeger,et al.  Solitons in conducting polymers , 1988 .

[30]  D. Batchelder.  The Study of Electronic Excitations of Polydiacetylenes and Resonance Raman Spectroscopy , 1985 .

[31]  R. Yen,et al.  Picosecond Dynamics of Photoexcited Gap States in Polyacetylene , 1982 .

[32]  Hiroshi Ohnuma,et al.  Absorption and Fluorescence Spectra of Polydiacetylenes (4BCMU and 3BCMU) in Solution , 1985 .

[33]  Koda,et al.  Photochromism and photoinduced bond-structure change in the conjugated polymer polydiacetylene. , 1987, Physical review. B, Condensed matter.

[34]  Baker,et al.  Excitonic and phonon-mediated optical Stark effects in a conjugated polymer. , 1989, Physical review letters.

[35]  L. Williams,et al.  Picosecond relaxation dynamics in polydiacetylene-pTS , 1987 .