Resonant hot charge-transfer excitations in fullerene-porphyrin complexes: Many-body Bethe-Salpeter study

Article

关键词: DENSITY-FUNCTIONAL THEORY;    DONOR-ACCEPTOR COMPLEXES;    TRANSFER EXCITED-STATES;    EXCHANGE-CORRELATION;    OPTICAL-ABSORPTION;    GREENS-FUNCTION;    ELECTRON-GAS;    BASIS-SETS;    ENERGY;    SPECTRA;   

DOI  :  10.1103/PhysRevB.87.245412

来源: SCIE

【 摘 要 】

We study the neutral singlet excitations of the zinc-tetraphenylporphyrin and C-70-fullerene donor-acceptor complex within the many-body Green's-function GW and Bethe-Salpeter approaches. The lowest transition is a charge-transfer excitation between the donor and the acceptor with an energy in excellent agreement with recent constrained density functional theory calculations. Beyond the lowest charge-transfer state, which can be determined with simple electrostatic models that we validate, the Bethe-Salpeter approach provides the full excitation spectrum. We evidence the existence of hot electron-hole states which are resonant in energy with the lowest donor intramolecular excitation and show a hybrid intramolecular and charge-transfer character, favoring the transition towards charge separation. Such findings, and the ability to describe accurately both low-lying and excited charge-transfer states, are important steps in the process of discriminating cold versus hot exciton dissociation processes.

【 授权许可】

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