Showing papers on "Pentacene published in 1993"
TL;DR: In this paper, the gas-phase electron attachment free energies for polycyclic aromatic hydrocarbons with the electron-transfer equilibria technique were measured with electron transmission spectroscopy.
Abstract: The gas-phase electron attachment free energies ΔG a o , where-ΔGa a o ≃EA, were measured for several polycyclic aromatic hydrocarbons with the electron-transfer equilibria technique. The EA values in kcal/mol are as follow: anthracene, 13.2; benz[a]pyrene, 18.2; perylene, 22.3; tetracene, 23.9; and pentacene, 31.2. These results, when combined with the literature value for naphthalene, -4.4 kcal/mol, based on electron transmission spectroscopy, lead to an approximately linear correlation with the one-electron (polarographic) reduction potentials determined in solution. However, the slope of the line is not equal to 1 as previously assumed
105 citations
TL;DR: In this paper, the authors studied the zero-phonon shift of pentacene molecules in a p-terphenyl host crystal at cryogenic temperatures and selected five molecules in the inhomogeneously broadened S1 ← S0 absorption band of the O1 site (592.32 nm).
71 citations
TL;DR: In this paper, the authors have shown that the performance of thin films of pentacene (PEN) with alkaline metals such as sodium, potassium, and rubidium can dramatically change from an insulator to an n-type semiconductor due to the doping.
Abstract: Donor doping of thin films of pentacene (PEN) with alkaline metals such as sodium, potassium, and rubidium was carried out Drastic changes in conductivities of PEN films from an insulator to an n‐type semiconductor due to the doping was observed Maximum conductivity of 28 Ω−1 cm−1 was shown in the film doped with rubidium Alkaline metal doping of thin films of other acene compounds such as tetracene and hexacene was also performed
69 citations
TL;DR: In this article, the orientations of the transition dipole moments of single pentacene molecules located in the O-1 and O-2 sites of p-terphenyl were investigated.
56 citations
TL;DR: In this article, the authors measured the long-wavelength edge features of pentacene spectra at 1.8 K and found that the main vibrational features in these spectra are similar in frequency and intensity to those obtained from the bulk sample with excitation near the center of the origin band.
Abstract: Dispersed fluorescence spectra of single molecules of pentacene in p-terphenyl at 1.8 K have been recorded by tuning the excitation laser to single-molecule features at the long-wavelength edge of the fluorescence excitation spectrum. The main vibrational features in these spectra are similar in frequency and intensity to those obtained from the bulk sample with excitation near the center of the origin band, indicating that the absorption features in the wings of the inhomogeneous distribution probably arise from normal pentacene molecules to within the resolution of this experiment. Prospects for the development of this technique are discussed
52 citations
Abstract: Pentacene/tetracene organic superlattices were formed by deposition on a glass substrate, and their structure was investigated by x‐ray diffraction and photoluminescence. For samples in which the number (n) of constituent pentacene (or tetracene) molecular layers within a period is such that n≥3, the first‐order x‐ray diffraction peak was found to consist of several equally spaced subpeaks. Comparison of the spectra with calculated structure factors established that a well‐defined superlattice structure was achieved in these samples. In contrast, samples with n<3 showed no evidence of superlattice formation. Photoluminescence spectra show clear correlation with the x‐ray results.
49 citations
TL;DR: In this paper, the fluorescence lifetime of single pentacene molecules in the O 1 site of p -terphenyl at a temperature of 1.8 K has been measured, and individual molecules were repetitively excited by monochormatic Fourier transform limited light pulses with a duration of 9 ns.
45 citations
TL;DR: In this paper, an electron spin echo spectrometer and pulsed nitrogen laser were employed to study the guest deuteration and host effects on the zero-field splittings (ZFS), hyperfine splitting, and the g values of the photoexcited triplet state of pentacene.
Abstract: An electron spin echo spectrometer and pulsed nitrogen laser were employed to study the guest deuteration and host effects on the zero-field splittings (ZFS), hyperfine splittings, and the g values of the photoexcited triplet state of pentacene. These studies were performed in a temperature range of 5 K to room temperature in four mixed crystals: pentacene-h 14 in p-terphenyl (PHPT), pentacene-d 14 in p-terphenyl (PDPT), pentacene-h 14 in benzoic acid (PHBA), and pentacene-h 14 in naphthalene (PHNA)
24 citations
TL;DR: In this article, the pressure dependence of the low temperature (15 K) absorption spectrum of pentacene impurities in a para-terphenyl host crystal is used to investigate the pressure and/or temperature induced triclinic to monoclinic phase change of the para-TERPYL host crystal.
Abstract: The pressure dependence (0–10 kbar) of the low temperature (15 K) absorption spectrum of pentacene impurities in a para‐terphenyl host crystal is used to investigate the pressure and/or temperature induced triclinic to monoclinic phase change of the para‐terphenyl host crystal. Due to the characteristic absorption spectrum of pentacene in these two crystal phases, the pentacene impurity proves to be a sensitive probe of the structure of the surrounding para‐terphenyl matrix.
14 citations
TL;DR: In this paper, the gas phase electron attachment free energies were measured for several polycyclic aromatic hydrocarbons with the electron-transfer equilibria technique, and the EA values in kcal/mol were as follow: anthracene, 132; benz[a]pyrene, 182; perylene, 223; tetracene and pentacene, 312.
Abstract: The gas-phase electron attachment free energies ΔG a o , where-ΔGa a o ≃EA, were measured for several polycyclic aromatic hydrocarbons with the electron-transfer equilibria technique The EA values in kcal/mol are as follow: anthracene, 132; benz[a]pyrene, 182; perylene, 223; tetracene, 239; and pentacene, 312 These results, when combined with the literature value for naphthalene, -44 kcal/mol, based on electron transmission spectroscopy, lead to an approximately linear correlation with the one-electron (polarographic) reduction potentials determined in solution However, the slope of the line is not equal to 1 as previously assumed
13 citations
TL;DR: In this paper, the authors showed that the electrical resistivities of pentacene thin films doped with iodine in the direction parallel to the substrate plane fit the T−1/3 dependence well.
Abstract: The logarithmic electrical resistivities of pentacene (PEN) thin films doped with iodine in the direction parallel to the substrate plane fit the T−1/3 dependence well. This indicates that the lateral transport of the film was governed by two‐dimensional variable range hopping. In contrast, the logarithmic resistivities of the films perpendicular to the substrate were observed to be almost independent of temperature and to be weakly T−1/2 dependent. This shows that the tunneling mechanism is predominant in perpendicular transport. Two‐dimensional conduction of the film was confirmed by these transport properties, which was expected from the intercalated structure of PEN film doped with iodine.
TL;DR: In this paper, temperature-dependent photon echo measurements for pentacene in naphthalene at high pressure (12.5 kbar) in a diamond anvil cell are presented.
TL;DR: In this paper, the change in the density of states of doped pentacene, 8.4 × 10 23 states·eV −1 ·cm −3, was estimated from the difference of the susceptibilities at the transition.
Patent•
02 Mar 1993
TL;DR: In this paper, a high sensitivity sensor having temperature switching function was constructed by forming the sensor out of a detection part composed of an organic charge moving complex comprising an electron donative molecule and an electron giving molecule, and a signal drawing part.
Abstract: PURPOSE:To provide a high sensitivity sensor having temperature switching function by forming the sensor out of a detection part composed of an organic charge moving complex comprising an electron donative molecule and an electron giving molecule, and of a signal drawing part. CONSTITUTION:A pentacene thin film is formed on a Pyrex glass substrate 5, for example. A gold thin film is layered on the thin film, so as to form a gold electrode. Doping is carried out by making iodine gas in contact with the pentacene thin film, so as to form a pentacene-iodine charge moving complex 1. After a gold wire 4 is connected to the gold electrode 2 by a carbon paste, it is sealed in a glass tube 6, and the gold wire 4 is drawn out of the sealed part, so as to manufacture a sensor. The electric resistance of the sensor at room temperature is approximately 1kOMEGA and when the sensor is heated, the electric resistance is rapidly increased at approximately 130 deg.C, until it reaches no less than approximately 10MOMEGA at approximately 150 deg.C. When the temperature of the tube 6 is reduced, the resistance at room temperature becomes 1kOMEGA, and reverse detection can be carrier out. The detection temperature can be adjusted by a combination of an electron donative molecule and an electron giving molecule.
TL;DR: In this paper, the electrical conductivities of thin films of acene compounds doped with iodine were studied, and it was shown that these electrical properties were strongly correlated with the degree of molecular orientation in the film.
Abstract: Structure and electrical conductivities of thin films of acene compounds doped with iodine were studied. In particular, doping of thin films of pentacene (PEN) with iodine caused characteristic changes in structure and electrical conductivity. The doped films exhibited high lateral conductivity above 102 S/cm with high anisotropy of 108 and well-defined layered structure in which iodine molecules intercalated between molecular layers of PEN. Metallic transport appeared in the highly ordered film at temperatures below 240 K. Transport behavior, lateral and perpendicular to the plane, was explained by two-dimensional (2D) variable range hopping (VRH) and by the tunneling mechanism, respectively. These electrical properties were strongly correlated with the degree of molecular orientation in the film.