相关论文: Do ultrafast exciton-polaron decoherence dynamics …
In high-performance solar cells based on polymeric semiconductors, the mechanism of photocarrier generation on $<100$-fs timescales is yet to be unravelled. In particular the dynamics of early-time electronic coupling between excitons on…
Organic semiconductors have the remarkable property that their optical excitation not only generates charge-neutral electron-hole pairs (excitons) but also charge-separated polaron pairs with high yield. The microscopic mechanisms…
In polymer:fullerene solar cells, the origin of the losses in the field-dependent photocurrent is still controversially debated. We contribute to the ongoing discussion by performing photo-induced charge extraction measurements on…
We report a theoretical description and experimental implementation of a novel two-dimensional coherent excitation spectroscopy based on quasi-steady-state photoinduced absorption measurement of a long-lived nonlinear population. We have…
In organic solar cells, photogenerated singlet excitons form charge transfer (CT) complexes, which subsequently split into free charge carriers. Here, we consider the contributions of excess energy and molecular quadrupole moments to the…
The photophysics of $\pi$-conjugated polymers has been of considerable interest over the last three decades because of their organic semiconductor properties. Primary photoexcitations, Frenkel excitons, can be probed optically by means of…
In polymeric semiconductors, charge carriers are polarons, which means that the excess charge deforms the molecular structure of the polymer chain that hosts it. This effect results in distinctive signatures in the vibrational modes of the…
Excitons diffusing to a charge-separating interface is a necessary step to convert energy into current in next-generation photovoltaics. In this report, made possible by a new ultrafast spectrometer design, we compare exciton dynamics…
The high flexibility of organic molecules offers great potential for designing the optical properties of light-active materials for the next generation of optoelectronic and photonic applications. However, despite successful implementations…
We investigated the photocurrent in poly(3-hexylthiophene-2,5-diyl) (P3HT):[6,6]-phenyl-C$_{61}$ butyric acid methyl ester (PCBM) solar cells by applying a pulsed measurement technique. For annealed samples, a point of optimal symmetry…
All-polymer solar cells gained substantial achievements in recent years, offering numerous unsettled subjects for mechanical researchers. Based on the Su-Schrieffer-Heeger model, we then simulate the ultrafast dynamics of charge-transfer…
We have previously demonstrated that in the context of two-dimensional (2D) coherent electronic spectroscopy measured by phase modulation and phase-sensitive detection, an \emph{incoherent} nonlinear response, due to pairs of…
The separation of photogenerated polaron pairs in organic bulk heterojunction solar cells is the intermediate but crucial step between exciton dissociation and charge transport to the electrodes. In state-of-the-art devices, above 80% of…
Multidimensional coherent optical spectroscopy is one of the most powerful tools for investigating complex quantum mechanical systems. While it was conceived decades ago in magnetic resonance spectroscopy using micro- and radio-waves, it…
The interaction of exciton and charge transfer (CT) states plays a central role in photo-induced CT processes in chemistry, biology and physics. In this work, we use a combination of two-dimensional electronic spectroscopy (2D-ES),…
Excitons are key quasiparticles determining the optical properties of solids. As such, they can be utilized to coherently control the electronic structure of materials using optical femtosecond pulses. Identifying the decoherence mechanism…
We present a systematic investigation of two-photon excitation processes in a GaAs-based microcavity in the strong-coupling regime. We observe second harmonic generation resonant to the upper and lower polariton level, which exhibits a…
The exciton dissociation and charge separation occurring on subpicosecond time scales following the photoexcitation are studied in a model donor/acceptor heterojunction using a fully quantum approach. Higher-than-LUMO acceptor orbitals…
A deep understanding of molecular photo-transformations is challenging because of the complex interaction between the configurations of electrons and nuclei. An initial optical excitation dissipates energy into electronic and structural…
In an intense laser field, an electron may decay by emitting a pair of photons. The two photons emitted during the process, which can be interpreted as a laser-dressed double Compton scattering, remain entangled in a quantifiable way:…