97765-42-9Relevant academic research and scientific papers
Electrical properties of 1,4-bis(4-(phenylethynyl)phenylethynyl)benzene and its application for organic light emitting diodes
Fenenko, Larysa,Shao, Guang,Orita, Akihiro,Yahiro, Masayuki,Otera, Junzo,Svechnikov, Sergei,Adachi, Chihaya
, p. 2278 - 2280 (2007/12/27)
We found that a phenylene ethynylene derivative, 1,4-bis(4-(phenylethynyl) phenylethynyl)benzene (BPPB), provides very high photoluminescence efficiency both in solution (ΦPL = 95 ± 3%) and thin films (ΦPL = 71 ± 3%); further, we observed blue electroluminescence (EL) of λEL (max) ～470 and 510 nm with an external EL efficiency of ηEL ～0.53% and maximum luminance of ～70000 cd m-2 at current density of ～2 A cm -2 with BPPB as an emitter; also we identified that BPPB functions as a hole transport layer in organic light emitting diodes. The Royal Society of Chemistry.
Geometrically homogenous series of covalently linked zinc/free-base porphyrin dimers of varying length; design, synthesis and characterization
Ljungdahl, Thomas,Pettersson, Karin,Albinsson, Bo,Martensson, Jerker
, p. 3087 - 3096 (2007/10/03)
Singlet excitation energy transfer, SEET, can be mediated by a bridge, connecting an energy donor and acceptor, via a superexchange mechanism. The mediation efficiency depends on the energy difference between the first excited states of the donor and the bridge, ΔEDB, as well as the donor-acceptor distance, RDA. We have previously constructed a series of donor-bridge-acceptor, D-B-A, systems that allowed us to study how SEET depends on ΔEDB. To expand this study into a second dimension, the distance dependence, a new series of D-B-A systems were constructed. This series was based on the same zinc/free-base porphyrin couple as the donor-acceptor pair in the previous series. Their relative orientation was also retained. In contrast to our first series, the bridges in the latter were of varying length. The bridges were oligo(phenyleneethynylene)phenylene (OPE) structures and the length was systematically changed by increasing the number of phenyleneethynylene units from 1 to 4. To obtain high quality samples, the D-B-A systems were assembled by a building block approach where the zinc and free-base porphyrins were introduced separately using Heck alkynylations. The performance of the OPE structure as a mediator and scaffold is discussed in terms of singlet excited state energies and flexibility. For the first time, when combining the topical D-B-A systems with our previous subset, a homogeneous series of D-B-A systems has been synthesized that allows for studies of both the distance dependence and the energy difference dependence of SEET. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Light-emitting efficiency tuning of rod-shaped π conjugated systems by donor and acceptor groups
Yamaguchi, Yoshihiro,Tanaka, Takahiro,Kobayashi, Shigeya,Wakamiya, Tateaki,Matsubara, Yoshio,Yoshida, Zen-Ichi
, p. 9332 - 9333 (2007/10/03)
In view of the increasing importance of highly efficient light-emitting materials in chemistry, biological science, and materials science, we investigated the light-emitting efficiency tuning of rod-shaped oligo(p-phenylene ethynylene)s (OPEs, trimeric to pentameric systems) by donor and acceptor groups, so that they emit the very intense fluorescence (Φf ≈ 1.0, log ε ≈ 5) at 460 nm as the desired wavelength region. This goal was achieved by side modification by MeO (donor) groups and end modification by a CN-substituted benzene ring or CF3-substituted pyridine ring (acceptor) of tetrameric p-phenylene ethynylene rod-shaped molecules (Φf = 0.96, λem = 458 nm, log ε = 4.96 for the former and Φf = 0.99, λem = 459 nm, log ε = 4.92 for the latter). The high Φf values for 11 and 12 are interpreted in terms of kr (radiative rate constant) and kd (radiationless rate constant). The linear relationship with a positive slope between Φf and the Hammett σ constant was found for the first time. It is found that kd rather than kr varies with σp-X. The photophysical properties (Φf, λem, λabs, log ε) were not so altered with the solvent polarity, which could be explained by the dipole moments in the excited and ground states. The results would be valuable for the molecular design of highly efficient light-emitting materials. Copyright
