Triplet states in a series of Pt-containing ethynylenes

By use of optical steady state and time resolved spectroscopy, we studied the evolution of the triplet excited state in a series of six ethynylenic polymers of the structure [-Pt(PBu3n)2-C≡C-R-C≡C-]n where the spacer unit R is systematically varied to give optical gaps from 1.7–3.0 eV. The inclusion of platinum in the polymer backbone induces a strong spin-orbit coupling such that triplet state emission (phosphorescence) associated with the conjugated system can be detected. Throughout the series we find the S1-T1 (singlet-triplet) energy splitting to be independent of the spacer R, such that the T1 state is always 0.7±0.1 eV below the S1 state. With decreasing optical gap, the intensity and lifetime of the triplet state emission were seen to reduce in accordance with the energy gap law.

[1]  Richard H. Friend,et al.  Electroluminescence emission pattern of organic light-emitting diodes: Implications for device efficiency calculations , 2000 .

[2]  Franco Cacialli,et al.  Molecular-scale interface engineering for polymer light-emitting diodes , 2000, Nature.

[3]  S. R. Forrest,et al.  High-efficiency fluorescent organic light-emitting devices using a phosphorescent sensitizer , 2000, Nature.

[4]  R. I. Personov,et al.  Phosphorescence of pi-conjugated oligomers and polymers. , 2000, Physical review letters.

[5]  Shuai,et al.  Singlet and triplet exciton formation rates in conjugated polymer light-emitting diodes , 2000, Physical review letters.

[6]  Stephen R. Forrest,et al.  EXCITONIC SINGLET-TRIPLET RATIO IN A SEMICONDUCTING ORGANIC THIN FILM , 1999 .

[7]  Luis G. Arnaut,et al.  Singlet and triplet energies of α-oligothiophenes: A spectroscopic, theoretical, and photoacoustic study: Extrapolation to polythiophene , 1999 .

[8]  A. Monkman,et al.  Measurement of the S0–T1 energy gap in poly(2-methoxy,5-(2′-ethyl-hexoxy)–p-phenylenevinylene) by triplet–triplet energy transfer , 1999 .

[9]  Joseph Shinar,et al.  DELAYED FLUORESCENCE AND TRIPLET-TRIPLET ANNIHILATION IN PI -CONJUGATED POLYMERS , 1999 .

[10]  Neil C. Greenham,et al.  PHOTOINDUCED ELECTRON TRANSFER FROM CONJUGATED POLYMERS TO CDSE NANOCRYSTALS , 1999 .

[11]  Richard H. Friend,et al.  Harvesting Singlet and Triplet Energy in Polymer LEDs , 1999 .

[12]  R. Friend,et al.  Evolution of lowest singlet and triplet excited states with number of thienyl rings in platinum poly-ynes , 1999 .

[13]  Yong Cao,et al.  Improved quantum efficiency for electroluminescence in semiconducting polymers , 1999, Nature.

[14]  W. Barford,et al.  Theoretical investigation of the low-lying electronic structure of poly(p-phenylene vinylene) , 1999, cond-mat/9901115.

[15]  R. Friend,et al.  Synthesis, Electrochemistry, and Spectroscopy of Blue Platinum(II) Polyynes and Diynes. , 1998, Angewandte Chemie.

[16]  M. Ratner,et al.  Spin effects on the luminescence yield of organic light emitting diodes , 1998 .

[17]  S. Forrest,et al.  Highly efficient phosphorescent emission from organic electroluminescent devices , 1998, Nature.

[18]  R. H. Friend,et al.  Charge separation in localized and delocalized electronic states in polymeric semiconductors , 1998, Nature.

[19]  C. Weder,et al.  Polarizing energy transfer in photoluminescent materials for display applications , 1998, Nature.

[20]  C. Weder,et al.  Incorporation of photoluminescent polarizers into liquid crystal displays , 1998, Science.

[21]  R. Friend,et al.  Synthesis and Electronic Structure of Platinum-Containing Poly-ynes with Aromatic and Heteroaromatic Rings , 1998 .

[22]  Markus Schwoerer,et al.  Evidence for triplet interchain polaron pairs and their transformations in polyphenylenevinylene , 1997 .

[23]  R. Friend,et al.  Spatial extent of the singlet and triplet excitons in transition metal‐containing poly‐ynes , 1996 .

[24]  David Beljonne,et al.  Influence of chain length and derivatization on the lowest singlet and triplet states and intersystem crossing in oligothiophenes , 1996 .

[25]  Alan J. Heeger,et al.  The exciton binding energy in luminescent conjugated polymers , 1996 .

[26]  Scott D. Cummings,et al.  Tuning the Excited-State Properties of Platinum(II) Diimine Dithiolate Complexes , 1996 .

[27]  R. Friend,et al.  Theoretical investigation of the lowest singlet and triplet excited states in oligo(phenylene vinylene)s and oligothiophenes , 1996 .

[28]  David Beljonne,et al.  Theoretical investigation of the lowest singlet and triplet states in poly(paraphenylene vinylene)oligomers , 1995 .

[29]  R. Friend,et al.  Optical spectroscopy of platinum and palladium containing poly‐ynes , 1994 .

[30]  Todd B. Marder,et al.  Synthesis and optical spectroscopy of linear long-chain di-terminal alkynes and their Pt-σ-acetylide polymeric complexes , 1994 .

[31]  R. Friend,et al.  Optical spectroscopy of triplet excitons and charged excitations in poly(p-phenylenevinylene) light-emitting diodes , 1993 .

[32]  Hans Wynberg,et al.  Alternate donor-acceptor small-band-gap semiconducting polymers; Polysquaraines and polycroconaines , 1993 .

[33]  Wei,et al.  Studies of photoexcited states in polyacetylene and poly(paraphenylenevinylene) by absorption detected magnetic resonance: The case of neutral photoexcitations. , 1992, Physical review letters.

[34]  Lane,et al.  Polarons and triplet polaronic excitons in poly(paraphenylenevinylene) (PPV) and substituted PPV: An optically detected magnetic resonance study. , 1991, Physical review. B, Condensed matter.

[35]  Bradley,et al.  Photoexcited states in poly(p-phenylene vinylene): Comparison with trans,trans-distyrylbenzene, a model oligomer. , 1990, Physical review. B, Condensed matter.

[36]  R. L. Elsenbaumer,et al.  Handbook of conducting polymers , 1986 .

[37]  K. Sonogashira,et al.  Studies on polyyne polymers containing transition metals in the main chain. VII. Synthesis and characterization of palladium‐polyyne polymers , 1982 .

[38]  K. Sonogashira,et al.  Linear polymers containing transition metals in the main chain , 1981 .

[39]  E. Würzberg,et al.  Energy gap law in the solvent isotope effect on radiationless transitions of rare earth ions , 1975 .

[40]  Joshua Jortner,et al.  The energy gap law for radiationless transitions in large molecules , 1970 .

[41]  W. Siebrand.  Radiationless Transitions in Polyatomic Molecules. II. Triplet‐Ground‐State Transitions in Aromatic Hydrocarbons , 1967 .

[42]  Digby F. Williams,et al.  Isotope Rule for Radiationless Transitions with an Application to Triplet Decay in Aromatic Hydrocarbons , 1967 .

[43]  G. W. Robinson,et al.  Electronic Excitation Transfer and Relaxation , 1963 .

[44]  G. W. Robinson,et al.  Theory of Electronic Energy Relaxation in the Solid Phase , 1962 .