Chapter 5 Optical Properties

Jacobsen, Claus Schelde

doi:10.1016/s0080-8784(08)62545-4

Cited by 14 publications

(10 citation statements)

References 236 publications

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“…The rather obvious antiresonance feature is an indication of the strong electronphonon coupling in the compound. Such a phenomenon is more commonly seen in organic conductor or superconductors as a result of significant electron-molecular vibration coupling [19,20]. The presence of such peculiar phonon structure unambiguously illustrates the very strong electron-phonon coupling in present doped diamond sample.…”

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confidence: 52%

Optical properties of boron-doped diamond

Wang

et al. 2006

Phys. Rev. B

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We report optical reflectivity study on pure and boron-doped diamond films grown by a hotfilament chemical vapor deposition method. The study reveals the formation of an impurity band close to the top of the valence band upon boron-doping. A schematic picture for the evolution of the electronic structure with boron doping was drawn based on the experimental observation. The study also reveals that the boron doping induces local lattice distortion, which brings an infraredforbidden phonon mode at 1330 cm −1 activated in doped sample. The antiresonance characteristic of the mode in conductivity spectrum evidences the very strong coupling between electrons and this phonon mode.

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confidence: 52%

Optical properties of boron-doped diamond

Wang

et al. 2006

Phys. Rev. B

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“…A very weak broad band around 1 eV can also be regarded as CT between two NDI •– cores. These bands in the near-IR to IR region only appear in the presence of intermolecular interactions. − In addition, a sharp signal ( g = 2.003) observed in the ESR spectrum confirms the existence of NDI •– species (Figure S6).…”

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confidence: 71%

Porous Molecular Conductor: Electrochemical Fabrication of Through-Space Conduction Pathways among Linear Coordination Polymers

et al. 2019

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The first porous molecular conductor (PMC), which exhibits porosity, a through-space conduction pathway and rich charge carriers (electrons), was prepared through electrocrystallization from Cd2+ and N,N′-di(4-pyridyl)-1,4,5,8-naphthalenetetracarboxdiimide (NDI-py). [Cd(NDI-py)(OH2)4](NO3)1.3±0.1·nDMA (PMC-1) was assembled by π–π stacking among one-dimensional (1D) linear coordination polymers. The NDI cores were partially reduced into radical anions to form conductive π-stacked columns, yielding (1.0–3.3) × 10–3 S cm–1 at room temperature. Moreover, the electrical conductivity was significantly enhanced by removing the solvent molecules from PMC-1, indicating that PMCs are promising as molecule-responsive conductive materials.

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“…Their similarity with PTM anion salts 7 confirm their anionic nature. However, the principal difference with PTM anions is a strong broad absorption (from ≈1600 up to more than 4000 cm -1 , reaching the NIR); this is attributed to a very broad charge-transfer band, called band “A” in the mixed-valence conducting organic compounds, due to the intermolecular electronic charge-transfer excitations. 1a, …”

Section: Resultsmentioning

confidence: 99%

“…The design of new organic ion radicals is a subject of current interest since these structural units are responsible for the unusual optical (NIR), magnetic, and electrical properties of the mixed-valence compounds 3 and some conducting polymers . However, very few organic mixed-valence compounds are known, most of them being formed from an electrically neutral, nonradical species by a single-electron addition or removal ( nondistonic ) .…”

Section: Introductionmentioning

confidence: 99%

Inert Carbon Free Radicals. 14. Synthesis, Isolation, and Properties of Two Strongly π−π Interacting Mixed-Valence Compounds: The Perchloro-4,4‘-ethynylenebis(triphenylmethyl) Anion Radical Potassium (18-Crown-6) Salt and the Perchloro-α,α,α‘,α‘-tetraphenyl-p-xylylene Anion Radical Tetrabutylammonium Salt

Domingo¹,

Castañer²,

Riera³

et al. 1997

Chem. Mater.

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The perchloro-4,4′-ethynylenebis(triphenylmethyl) anion radical (11) potassium 18-crown-6 salt and perchloro-R,R,R′,R′-tetraphenyl-p-xylylene anion radical (15) tetrabutylammonium salt have been isolated in pure form as solids perfectly stable in the air and moisture, withstanding temperatures up to 200 °C. Their physical and chemical properties have been studied using UV-vis, NIR, IR, ESR, cyclic voltammetry, magnetic susceptibility, and electrical conductivity and compared with other already reported and structurally related perchlorotriphenylmethyl systems in which an intramolecular "spin-charge exchange" takes place. In contrast with those compounds, the acetylene anion radical 11 shows an unusual band in the vis-NIR region (754 nm, 37.7 kcal/mol), not present in its corresponding biradical 10 and dianion 9, and the Thiele anion radical 15 shows a typical, but bathochromically shifted ca. 10 kcal/mol, radical band and an unusual NIR band at 1342 nm (21.2 kcal/mol) of high intensity. Application of Hush's theory of mixed-valence class III compounds to these unusual bands for PTM compounds, gives the values of ca. 18 and 10 kcal/mol for the resonance energy of 11 and 15 respectively. The close coincidence of these theoretical values with those obtained by comparing the UV-vis spectra of 11 and 15 with the PTM anion radical systems without resonance interaction can be regarded as a preliminary test of the validity of Hush's theory of organic mixed-valence class III compounds. The cyclic voltammograms of anion radicals 11 and 15 indicate that their precursors, the biradical 10 and perchloro-Thiele hydrocarbon 16 have suitable redox potentials as acceptor components of electrically conducting charge-transfer complexes. 11 and 15 present magnetic properties similar to those of PTM radicals, but as a consequence of the "spin charge resonance" they show a halving of the hyperfine coupling constants. More spectacular differences are shown in the electrical conductivity of 11 and 15 with values of 10 -4 and 10 -6 S cm -1 , respectively, which can be a consequence of their molecular design as suggested the ∆E 1/2 differences (6.4 vs 12 kcal/mol). These conductivity values are in the range of the corresponding TCNQ salts.

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Chapter 5 Optical Properties

Cited by 14 publications

References 236 publications

Optical properties of boron-doped diamond

Optical properties of boron-doped diamond

Porous Molecular Conductor: Electrochemical Fabrication of Through-Space Conduction Pathways among Linear Coordination Polymers

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