Pentacene

About: Pentacene is a research topic. Over the lifetime, 5051 publications have been published within this topic receiving 161481 citations. The topic is also known as: 2,3:6,7-dibenzanthracene & benzo[b]naphthacene.

Effects of Heteroatoms of Tetracene and Pentacene Derivatives on Their Stability and Singlet Fission

Abstract: The effects of the introduction of an sp2-hybridized nitrogen atom (═N—) and thiophene ring on the structure geometries, frontier molecular orbital energies, and excited state energies related to singlet fission (SF) for some tetracene and pentacene derivatives were theoretically investigated by quantum chemical methods. The introduction of a nitrogen atom significantly decreases the energies of frontier molecular orbitals and hence improves their stabilities in air and light illumination. More importantly, it is helpful for reducing the energy loss of the exothermic singlet fission of pentacene derivatives. For fused benzene-thiophene structures, the (α, β) connection pattern could stabilize the frontier molecular orbitals, while the (β, β) connection pattern can promote the thermodynamic driving force of singlet fission. These facts provide a theoretical ground for rational design of SF materials.

Physisorption-like Interaction at the Interfaces Formed by Pentacene and Samarium

Abstract: We have investigated the nature of the interaction between samarium (Sm) and pentacene, and the energy level alignment at the resulting interfaces. The valence electronic structure of in situ prepared samples, i.e., pentacene evaporated onto Sm surfaces and vice versa, was investigated with ultraviolet photoelectron spectroscopy. Pentacene appears to physisorb on the metal surface. Sm also appears to interact weakly when evaporated on the organic material, forming clusters at low coverage. Indications of a valence change of Sm upon evolution from clusters to metallic film are found. The highest occupied molecular orbital of pentacene is measured at 1.85 eV below the metal Fermi level EF for both evaporation sequences. Estimating the energy of the lowest unoccupied molecular orbital of pentacene using the transport gap, we obtain a barrier of only 0.35 eV for the injection of electrons from the metal into the organic material.

Nonempirically Tuned Long-Range Corrected Density Functional Theory Study on Local and Charge-Transfer Excitation Energies in a Pentacene/C60 Model Complex

Abstract: The local and charge-transfer excitation energies in a pentacene/C60 complex, which is prototypical of the minimal structural unit of the donor–acceptor heterojunction in pentacene/C60 organic cells, are evaluated using the time-dependent long-range corrected density functional theory (TD-LC-BLYP) method in comparison with those estimated from the experimental data for pentacene and C60. In the framework of the tuned range-separated hybrid (Livshits et al. J. Phys. Chem. A2008, 112, 12789), we tune the range separating parameter (μ) of the LC-BLYP functional by imposing the many-electron self-interaction-free (ME-SIF) condition on the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of pentacene and C60. The TD-LC-BLYP method with μ = 0.20 is found to succeed in the semiquantitative description of both the local and charge-transfer excitation energies in the pentacene/C60 complex.